MERCEDES - BENZ

The Mercedes R231

From the SL350 to the SL65 AMG

2012 – 2020

By Bernd S. Koehling

Copyright  2022  Bernd S. Koehling

All rights reserved

FOREWORD

When the first SL was launched in 1952, nobody envisioned that the name “SL” would develop into one of the better-known household words in the world. The first street-going version of that car, the famous Gullwing, cemented the importance of that name. The Mercedes SL has developed into an automotive icon. While the early models were more developed with an eye on class, elegance and most of all performance, the more modern versions have added comfort and luxury to it. So much in fact that many aficionados of the marque have argued that the “L” in SL stands nowadays not anymore for “Leicht” (light) but for “Luxury”.

But carrying a name such as “SL” is not only a tradition, it can also be a burden. When power steering and automatic transmission was first introduced in the Pagoda SL in 1963, many critics especially in Europe lamented this to be the death knell to the venerable SL. At that time management was luckily wise enough not to listen to those remarks, but to look at what the markets wanted from a sports car. And one of the biggest markets for such cars was without doubt North America.

Thus it came as no surprise that the successor of the W113 SL was even more geared towards the demands of this market. Again critics in Europe argued the car would have too much of an American influence, this time in its design. Power steering and automatic transmissions had by now been grudgingly accepted. Little did they know how successful this “Americanized” SL should become. After the G-model, the R107 developed into the car with the longest production run of any Mercedes-Benz.

It seems that Daimler-Benz engineers have learned to live with such kind of burden, as so far every new SL was despite some initial criticism a car that was able to set new standards and thus become part of a breed that exists, as many journalists and car aficionados see it, in a class of its own.

When the R230 was launched in 2001, it was again a technological breakthrough in its market. And for the first time the SL carried its steel roof along. The vario steel roof was not a first for Daimler-Benz and also not a first in the large roadster class; where it was seen already on the Lexus SC430. New technical features, combined with a convincing design, ensured that the R230 quickly found a loyal following especially in the form of the SL500/550.

And then the all-aluminum R231 became available in 2012. Mercedes engineers claimed that its development was one of the most difficult technical tasks they had to face. From a technical point of view the car was a masterpiece, also its build quality was top notch. Yet the R231 was not seen as much an innovator as its predecessors. But what potential customers and the press criticized most, was the SL’s design. The somewhat confused front and especially the rear with its oversized taillights was for some buyers difficult to swallow. The 2016 upgrade (MOPF) helped to clear up the front, but the rear was left more or less untouched. No wonder that despite the car’s technical qualities, sales reached over time a level never seen with any previous SL generation. It also did not help that Mercedes had created with the S-Class cabriolet and the AMG GT roadster strong in-house competition, although marketing always claimed that those two cars were targeted at different customer groups. Unfortunately, those customers saw it a bit differently, which resulted in the fact that in 2019, the SL’s last full year of production, just 294 units were sold in Germany for example.

But and this is a big but, for those people, who own the R231, the car was and is great fun and as the quality was from the beginning much better than that of the R230, very few had major issues with it. The ABC system, just to mention one of the SL’s nice optional features (standard on the AMG cars), was a hotly debated item among R230 owners. So far it has rarely caused concern among R231 owners, if properly maintained. The same goes for the vario roof, which some owners say they would have loved to see also with the new R232.

This 2013 book was completely revised and covers the SL R231 with all its variations, AMG versions, special editions and some of the tuner activities such as models from Brabus, FAB Design and RENNtech. I will take you along for an exciting test drive in an SL63 AMG and we will discuss, what to watch out for, when you plan your R231 purchase. We will also have a brief look at the new R232. This book comes with plenty of recent non-Daimler AG photos, this includes pictures of the suspension.

I would like to thank you for having purchased this book and I hope you will enjoy reading it.

September 2022

Bernd S. Koehling

CONTENT

Foreword

The Cars

SL350, SL400/450, SL500/550, SL63, SL65 AMG R231 (2012 – 2020)

A first for an SL: the aluminum body

A slightly revised design

History of the vario roof

More refined equipment features

Technical aspects: the engines

-The transmission

-The suspension

Prices and Edition 1 model

The SL63 AMG

-Technical aspects

-Body and interior

The SL65 AMG

-Technical aspects

-Body and interior

SL65, 45th Anniversary Edition

The SL400 replaced the SL350

The 2016 facelift

Technical aspects

The AMG models

“Special Edition” models: Edition 2Look

-2014 World Championship Collector’s Edition

-Mille Miglia 417 Edition

-Designo Edition

-Grand Edition

The Tuning scene: Brabus

-RENNtech

-FAB Design

-Others

Driving the SL63 AMG

Alternatives to the R231

Technical chapters

Active body control—yes or no

The R231’s VIN explained

The R231’s data card

The COMAND system

Extras and option packages

Updates and facelift (MOPF) overview

R231 buyer’s guide

-In a nutshell

-Body

-Engines, transmission

-Suspension (ABC system)

-Wheels and brakes

-Interior

Trouble-shooting the vario roof

Which R231 version to choose

Technical specifications: General Data

-Performance

-Transmission

-Chassis

-Power and torque curves

Production data

Exterior color options

Interior color options

Interior trim options

Wheel options

Outlook to the SL R232

About the author

Other books by the author

Free book offer

A first for an SL: the aluminum body

Although the car had grown in proportion: 5 cm (2 in) in length to now 4,612 mm (181.1 in), 57 mm (2.2in) in width to 1,877 mm (73.6 in) and 18 mm (0.71 in) in height, it was (depending on the version) up to 140 kg (308.6 lbs) lighter than its predecessor. This says a lot about the engineering efforts at Mercedes-Benz to get away from the image of a boulevard cruiser. With the exception of the windshield frame, which was made from a mixture of aluminum and high-strength steel to protect against rollovers, most of the body was made from aluminum, a first for an SL.

Also, the steering knuckles and suspension arms on the front axle plus the suspension components on the rear axle were made from aluminum. The body alone had some 110 kg (242.5 lbs) less weight than the steel body of the R230. The roof and the panel behind the 65 l (17 gallon) tank were even made from lighter but more expensive magnesium.

The trunk lid, as a first in a mass-produced car, had its inner frame made from a lightweight carbon-fiber composite material, which was bonded to a plastic outer shell. It allowed the engineers to integrate all antennae for the radio, phone systems and navigation into the panel without the problems that would come from a steel shell.

The R231 was 110 kg (242.5 lbs) lighter than its predecessor, most of the reduction came from the aluminum-intensive body. Only the windshield and roof frames were still made of steel

The front wall of the aluminum body-shell was the biggest aluminum cast component made in large series for vehicle bodywork. The two large holes were used for the Frontbass loudspeakers

Another benefit of the new structure and its advanced bonding technique was its improved torsional rigidity, safety and reduced vibration characteristics.

All components had been optimized for their specific task, meaning different kind and strength of aluminum were used depending on the purpose of the individual component. The underbody was completely revised and increased the roadster’s stiffness by some 20 percent.

Despite the fact that the car was lighter, with all the luxury and safety features on board, it still had a weight of 1,790 kg (3,947 lbs). Daimler AG’s marketing personnel surely saw it differently, but the “L” in SL that once stood for Light as in lightweight, had forever given way to “L” for Luxury.

But in all fairness to the company, it was a development not only seen with the SL, it was a development that all car manufacturers had to face. Nobody would accept the SL to come along like a British Morgan Roadster. So, to keep the car with all its technological, safety and comfort enhancements at around 1,800 kg, was quite an achievement.

Most basic body construction was done by robots

Later stages in the production process required of course manual input

A slightly revised design

Judging the SL by its appearance, it was not that much of a new design as some might have hoped for. Although the front was longer and the design even more angular than before, from the outside it looked merely like a warmed-up version of the 2008 facelift of the previous R230. Looking at the long and distinguished SL history, this might turn out in future to be its biggest downfall, when considering potential resale values. On the other hand, it was welcome news to 2008 and later R230 owners, as it helped to secure their cars’ value.

Early design sketches

Early interior proposal

At the front, the radiator grille, which was no longer visually integrated into the hood but designed separately, now stood upright. The Mercedes-Benz brand logo was integrated in the radiator grille with just one center strut. Compared with the predecessor, the headlights had been positioned further out, but retained their tilted position in the slope. The outer areas of the bumper now also housed the daytime running lights on the R 231 in the form of LED light strips. The side line rose only minimally toward the rear. The side air intake on the fender had been slightly enlarged compared with the previous model. In contrast to the predecessors, the rearview mirrors with integrated turn signals were located on the door flanks, as they were in the CLS.

While the front bore similarities with the SLK, the sideline was close to the SLS and the rear was still “the same slightly unwieldy looking bustle back-end”, as Autocar in the UK puts it in their March 2012 review. The rear lights appear to suffer from a confused basic silhouette that was trying to integrate the different creases and a weak swage line into a coherent whole. In contrast to the master pieces R129 (Bruno Sacco and team) and the first R230 (Peter Pfeiffer and team), the R231 suffered from an excessive front overhang to which unnecessary additional visual weight was added by the bluff silhouette of the front. In addition, even high-spec examples appeared somewhat under-wheeled.

Sadly, and unlike all its esteemed predecessors, it was a mixture of various Mercedes models and when parked next to an SLK and SLS, it will be less easy to distinguish it from the others.

On the other hand, to judge the car just by its design is a bit unfair to the car and the people, who developed it. Daimler-Benz chief engineer Jürgen Weissinger even said that the R231 was the biggest step that his engineers (not the designers!) had taken from one SL generation to the other.

The longer front is clearly visible in this picture

A 2010 R230 (above) vs the new R231

Dr Zetsche presents the R231 officially at the January 2012 Detroit Auto Show

Like its predecessor, the new SL came along with a vario-roof, that Daimler AG had first offered in the 1996 SLK. If you like to know a bit more about the history of such a roof, the next short chapter might interest you.

History of the vario roof

In most publications the interested reader will discover that the first car equipped with a folding-hardtop roof was a Peugeot 401 from 1934. This is correct, when one considers electrical hardtops only.

But this is just half the story, as the concept to have an all-weather removable metal top in an automobile dates back further. And it did not start in France, but in the United States of America. Benjamin Ellerbeck from Salt Lake City, Utah was an engineer with a keen interest in everything automotive.

By autumn 1919 he had worked out the basic design of a shiftable/retractable top for open cars, and by the early 1920s he had built a number of 1/8 scale models to demonstrate how his invention worked to potential clients. In 1921, he was granted a patent (US patent no. 1.379.906) for his shiftable top. Jumping forward somewhat, in December 1930 he was granted another US patent for a roadster that featured a second windshield for the rumble seat.

Although he was fairly enthusiastic about his invention, he had so far failed to attract a major customer to apply his ideas. Therefore, in 1922 Ellerbeck bought a 1919 Hudson Super Six, to serve as real world model for his innovative top. In order to make his new roof fit, he had to rebuild major parts of the Hudson. But the result was an attractive car, which looked especially inviting with the top down. Once closed, the overhang above the windshield looked similar to a giant air scoop or sun visor.

One problem was the fairly complicated mechanism to manually raise and lower the top. Costly to produce, it scared off quite a few possible customers. So in 1923 he changed his creation by letting the roof rest on landau bars, which were secured to the ends of a cross shaft passing through the body.

The previous creation offered straight diagonal arms, which were located inside of both body and top. The top was a metal frame with either fabric or metal cover. In lowered position, it would settle flush on the rear deck. In both lowered and raised positions it was secured with clamps. Still, despite his design changes, he had not found an interested party for the innovative top. So in 1925 he wrote a lengthy letter to Packard Motor Company, trying to interest them in his creation. In his letter he stated that he understood the car manufacturer’s desire to draw the line somewhere in the diversity of body styles.

Then he continued in his letter that he was convinced a Packard roadster would leap in favor if given a modern top construction. Unfortunately, Packard declined, but this did not stop his enthusiasm for his design. Ellerbeck even managed to get his design covered in an article by a British car magazine in the early 1930s, but also saw no interest forthcoming from any foreign manufacturer.

The 1929 stock market crash and following economic crisis certainly did not help and when interest in roadsters decreased towards the mid-1930s, so too did all effort from Benjamin Ellerbeck, who had fought so hard for over 15 years to have his innovative concept accepted. Like so many good ideas, it was probably ahead of its time.

The top for the Hudson was altered, as it now sat on top of the car’s rear section

An opening in the roof left room for additional passengers

Although almost forgotten, the concept was not dead entirely. A French dentist, who, just like Ellerbeck, held a keen interest in everything automotive, picked up Ellerbeck´s idea in 1930 in Europe. Because next to making a living as a dentist, George Paulin was also a gifted part-time automobile designer. The shiftable top concept was re-evaluated, simplified and it finally evolved under Paulin into the first power-operated retractable hardtop and consequently was patented by him in 1931.

On his side of the Atlantic, no one showed any interest, initially, in his concept either. Luckily, however, in autumn 1933 that changed, when Peugeot`s Paris car dealer Emile Darl`mat (a friend of Paulin), introduced the dentist to French coachbuilder Marcel Pourtout. Pourtout was immediately intrigued by Paulin´s patent and all three worked on making the retractable top happen. It was Paulin’s luck to have a large car dealer and a respected coachbuilder at his side, support that Ellerbeck unfortunately never enjoyed.

In May 1934, Carosserie Pourtout used a mid-sized Peugeot 402BL, supplied by Darl`mat, to introduce its Eclipse Decapotable (retractable roof). The revolutionary car gained considerable news coverage, which in turn brought Peugeot management into contact with Paulin. In 1935, he convinced the company of the virtues of his novel concept and consequently sold them his patent.

Peugeot 401 Eclipse: once the top was lowered, there was no luggage space left

In order to further support the idea, Paulin worked from 1934 till 1938 as Pourtout`s designer and helped to launch the system on cars such as the Peugeot 301, 401 and 601. 79 of Peugeot Type 401 and 473 of Peugeot Type 402 were produced with this roof. Sufficient space for the large metal roof was vital, so of all vehicles some 400 were built on the extended sedan chassis of the “Familiale Limousine”, which had a length of some 5,30 m (210.4 in). The extended chassis made the cars relatively expensive.

To mitigate that, it was decided to offer those cars with a manually operated top only. Most customers did not mind, since it was relatively easy to manually raise or lower the top. Sadly, only 34 Eclipse Decapotables survived today. Other vehicles designed with a retractable roof by Paulin and produced by Pourtout include the Italian Lancia Belna and various models from French car manufacturers Hotchkiss and Panhard.

The first American car to feature a retractable hardtop after the failed Ellerbeck attempt was the 1941 Chrysler Thunderbolt Roadster, produced to help improve Chrysler`s image among consumers. It must have been one of the first American dream cars and was designed by Alex Tremulis. Four of the five Thunderbolt ever built are known to have survived.

The 1941 Chrysler Thunderbolt Roadster. Very little is known about these cars. Its turning radius must have been huge

Ford picked up the idea of a retractable hardtop in 1956 to offer a Fairlane 500 Skyliner for the model years 1957 to 1959. The Skyliner was a full-sized two-door offer with a fairly complex electrically-operated hardtop. The top had a fold at the front, which disappeared with the rest of the roof under a long trunk lid. Compared with the Peugeot roof, this was a pure high-tech design.

Ford Fairlane 500 Skyliner: the roof looked complicated, but was reliable and must have been stunning to watch in motion in the 1950s

The Ford Fairlane driver did not have to do anything but to push a single button, and everything else happened as if by magic. The system was equipped with three electric motors that drove four jacks to lift and stow the top, four locking mechanisms to hold the top in place, ten solenoids and another four electric motors to lock the doors and trunk.

Each of the seven electrical motors had its own circuit breaker and 186 m (610 ft) of wiring was required to make this all work. The big Ford was with a length of 5.35 m (210.8 in) just 5 mm longer than its French predecessor, which did not have the split roof. And according to period reviews, the Ford´s top worked reliably, despite its complicated set-up. In those three years of production, Ford sold a total of 38,394 units.

Mitsubishi offered, in 1995 and 1996, a special edition of its 3000GT model. It was shipped from its Nagoya, Japan factory to ASC (American Sunroof Company) in California in coupe form. In California, it was transformed to the first modern car with a folding hardtop, and called “3000GT Spyder”. Like the Ford Skyliner, the roof opened fully automatic with the push of a button. With only 1,618 units sold, it was abandoned in 1996. It can be assumed that the car was Mitsubishi’s quick answer to the 1994 SLK presentation in Turin and Paris.

But shipping it first from Japan to ASC, where the top had to be chopped off, the chassis strengthened and the folding hardtop installed, made it a pretty expensive exercise. Therefore, it was no wonder that sales remained low and the project was quickly abandoned.

The interesting Mitsubishi 3000GT Spyder was unfortunately killed by its high price

More refined equipment features

In the interior, the Roadster got a leather triple-spoke steering wheel with aluminum double strut. Also new was the instrument cluster, which continued to have two clearly drawn analog round instruments, each with a further small round instrument. Between these, however, there was now an 11.4 cm multifunction display. A large trim element was attached to the instrument panel, which was probably intended to increase the value.

The central display of the navigation system with a diagonal of 17.8 cm (7 inch) was located between two aluminum cross-design air vents, which showed borrowings from the SLS AMG, and was now integrated into the upper part of the instrument panel.

Below the screen was a control unit that flowed up to the armrest and consisted of two separate compartments; starting at the top with the controls for the radio and navigation system and below that the climate controls. The control knobs were made of aluminum. The radio and navigation system were operated by a rotary and pushbutton located in front of the center armrest. Next to it is the now significantly smaller automatic selector lever.

Standard Equipment

The SL came with an impressive array of standard features. This included:

-          Adaptive Brake (An electronic control enables the hydraulic, dual-circuit braking system to provide support functions which further improve safety and comfort. These include priming of the braking system in critical situations: the braking system interprets rapid removal of the driver’s foot from the accelerator as an emergency braking situation. In this case ADAPTIVE BRAKE increases the pressure in the brake lines and brings the brake linings into light contact with the brake discs, so that they are then able to bite immediately and with full force when the brake pedal is depressed. In this way the system supports the functions of Brake Assist BAS)

-          Active Yaw Control GMR (for Giant Magneto Resistive), which directs torque laterally from the rear differential to the wheels on either side, thus creating yaw moments.

-          ASR (Anti Slip Regulation, better known as traction control), ABS, ESP

-          BAS (Brake Assist System, an electronic system that interprets the braking behavior of the driver and initiates the full braking effect when it identifies an emergency situation. This reduces the braking distance substantially)

-          7G-Tronic Plus 7-speed automatic transmission with a gearshift indicator and ECO Start-Stop,

-          Crash-active Neck-Pro head restraints and six airbags - two-stage airbags driver and front passenger, two sidebags in the seats, which protected the upper body in the event of a side impact, and two headbags in the doors that covered the side head impact area,

-          Active hood that raises 85 mm in the event of a collision, for example with a pedestrian

-          Attention Assist (when Attention Assist finds a cause for concern it will instruct the driver to take a break with both audio and visual alerts; a warning

-          sound is played and a picture of a coffee cup flashes on the dashboard)

-          Hill-start assist (it works by sensing the car is on an incline and holding the brakes for a few seconds – even after the handbrake has been released – until the clutch’s biting point has been found and the car begins to move forward)

Other goodies included an Electric Parking Brake and the Comand radio. From the SL500 model upward, the Comand Multimedia System, which played back in 3D and included Linguatronic voice control, was standard. This also featured Internet access. The Intelligent Light System was first introduced in 2006 on the E-Class. It offered five different bi-xenon light functions, each of which was suited to typical driving or weather conditions:

Country mode

Motorway mode

Enhanced fog lamps

Active light function (Advanced front-lighting system (AFS))

Cornering light function

Furthermore, a heated rear window, heat-insulating green glass, heated exterior mirrors, a rain sensor, eight speakers with front bass system, a suspension with adaptive damping system, the Pre-Safe occupant protection system and the so-called Torque Vectoring Brake, a braking system that makes unilateral braking interventions on the inside rear wheel to prevent understeer, were part of the standard equipment.

AirScarf was a very popular option with all SL versions

The Front Bass System, mentioned on the previous page, included a new loudspeaker architecture, which found its origin in the R231. The cavities of the aluminum structure on the side member were used as a resonance chamber for the amplifier and sound box, which should result in a further improved sound experience. Due to the changed arrangement, instead of the mid-bass drivers, there were now additional storage options in the door.

Optional Equipment

Optional extras included the Active Body Control suspension, Multifunction Steering Wheel in leather/wood finish, Airscarf headspace heating, a Panoramic Roof (standard from December 2012), which was also available with Magic Sky Control on request. After the SLK R172, the Magic Sky Control system was available in the R231 as second car. This was a switchable glass roof that had its origins in the Maybach. The difference to normal glass roofs was that the Magic Sky Control kept the heat and the sun's rays out of the interior; it could also be variably darkened or brightened. When switched on, the temperature on interior parts such as armrests was up to ten degrees Celsius lower than with conventional green glass.

The roof worked through the physics of a plate capacitor: When an electrical voltage was applied to the glass structure, particles in the glass aligned themselves so that light could pass through the pane. If, on the other hand, the voltage was left off, the particles remained randomly aligned. As a result, the light was partially blocked and the pane remained dark. Accordingly, the interior heated up less.

Other extras were an Electric Wind Deflector, a six-disc DVD changer and a TV tuner. In addition, the Harman Kardon Logic 7 surround sound system with 14 speakers and an output of 600 watts or the Bang & Olufsen BeoSound AMG surround sound system with twelve speakers, two tweeters and a total output of 900 watts.

Available as an option was also the keyless access system Keyless-Go. It included hands-free and touch-free opening of the trunk and, for the first time in a vehicle, the same process of closing it. Another assistance system was Distronic Plus. This feature used built-in radar to bring you up to speed, brake as necessary, and maintain a safe distance from the vehicle in front of you. Other optional assistance systems were Pre-Safe Brake, Active Lane Departure Warning and Active Blind Spot Assist.

Safety and comfort could be extended further with the Speed Limit Assist, which used an on-board camera (inside of the windscreen) to read speed-limit signs, which will then be shown on the display in the instrument cluster. Safety was not only vital for the car’s passengers; it was also important for pedestrians. A built-in sensor system was capable of registering an impact with a pedestrian and operated at speeds between 25 and 55 km/h (15 and 35 mph). Called Active Hood, it raised the hood instantly by some 85 mm. This resulted in lower acceleration values for the pedestrian’s head during impact and should help to reduce the risk of severe injuries.

The Active Parking Assist was not really new, but new to the SL. It was a convenience feature that could detect with the help of ultrasound sensors suitable parking spaces and automatically steer the car into that space.

In the event of a collision with a pedestrian, the hood lifted up at its rear by 85 mm in order to lessen injuries

The Magic Vision Control system was only available on select models, like the SL and GLE. It helped keep your front window clean and featured wiper blades with laser-cut holes that produced a highly precise spray of washer fluid directly in front of the moving wipers. The system helped eliminate the brief, vision-blocking spray across the full windshield that happened with most vehicles. Another benefit was a reduced overspray and runoff. In addition, since the washer fluid reservoir, lines and even the wiper blade were heated, it was very effective in cold weather.

Another helpful related feature were rain-sensing windshield wipers. These wipers would automatically adjust their speed and frequency according to how heavy the rain was falling.

“Keyless-Go” included hands-free opening and closing of the trunk

On top, various leather upholstery, aluminum and wood trim options were also part of the long list of extras.

A multitude of designo options was again available

As already with the R230, the limited rear space was too small for luggage. Separate foldable rear seats like in the R107 and R129 could not be ordered anymore

The optional wind stop device could be raised electrically

Technical aspects

The engines

With higher fuel prices and increased environmental awareness it was no surprise that fuel economy was rather high on the engine improvement agenda, so the displacement of the much-loved SL500/550 M278 V8 power plant (internal code: M278 DE46 AL) was reduced from 5.4 L (333 cu in) to 4.663 cc (284.6 cu in). It now had a bore of 92.9 mm and a stroke of 86 mm.

However, power output of this twin-turbo Blue EFFICIENCY called engine increased some twelve percent to 435 hp at 5,250 rpm. And maximum torque gained an even more impressive 32 percent from 530 Nm (391 lbs-ft) to 700 Nm (516 lbs-ft) from 1,800 rpm onwards. In June 2015 the power output increased to 455 hp.

The M278 was developed from the previous M273 V8, and shared with it the aluminum engine block, Silitec silicon/aluminum low friction cylinder liners and its bore pitch. The M273 engine was naturally aspirated, which meant that contrary to forced induction through a turbocharger or supercharger, it relied with its oxygen intake solely on atmospheric pressure.

The V8 had a more appealing engine cover than the R230. Its design was not shared with the V6

A look inside the V8 engine

The new M278 was equipped with dual turbocharges, one per cylinder bank, producing 0.9 bar boost pressure. The turbocharger was a turbine-driven forced induction device that increased an internal combustion engine’s power output and overall efficiency by pushing additional air into the combustion chamber.

Contrary to the port-injected M273, the M278 featured direct fuel injection with piezo-electrically actuated fuel injectors. The fuel was highly pressurized and then injected via a common rail fuel line directly into the combustion chamber of each cylinder. A conventional multipoint fuel injection system would inject fuel into the cylinder’s intake tract or cylinder port. Injecting fuel directly into the combustion chamber could only be done under high pressure, whereas low pressure was sufficient for an intake tract or cylinder port injection.

Two benefits of the direct injection were an improved fuel efficiency and reduced emission levels. And combined with powerful electronic management systems, it meant that the more advanced direct fuel injection did not come with a significant manufacturing cost penalty.

Unfortunately, there were disadvantages too. The direct injection with higher fuel pressure added to the engine’s complexity and will potentially increase maintenance costs for the car’s owner. Traditional multi-port injection systems had the fuel pass by the intake valve. This acted automatically as a cleaning agent for the valve. Direct injection systems did not have this feature, so carbon would build up over time on the back of the intake valve, which could eventually lead to engine problems, if not checked at regular intervals.

Direct injected engines required filters (which most such engines did not have yet), as they produced a high amount of nitrogen oxides under load. It meant the engine would run at higher internal temperatures, which added to the air pollution. Older gasoline engines did not produce such an amount of nitrogen oxides, as air and fuel were better mixed. With its name now even further removed from the engine displacement, the new SL500/SL550 burned an impressive 22 percent less fuel, when compared with the R230 SL500. It accelerated in just 4.7 seconds from zero to 100 km/h, eight tenths less than the R230, while again being electronically limited to a top speed of 250 km/h (155 mph). Neither were slouches, not that drag racing had ever been the SL’s thing.

An ECO start/stop function was standard for all engines and the power plant was mated to the 7G-Tronic automatic transmission, which was already used in the predecessor, but had been further optimized for greater fuel efficiency. As a first for a Mercedes V8 engine, the M278 was exempted in the US from the gas guzzler tax.

Although the engine displacement of the SL350 remained with 3,499 cc (213 cu in) unchanged, the improved V6 M276 power plant (internal code: M276 DE35) delivered now 306 hp (R230: 272 hp) at 6,500 rpm, offered 370 Nm (273 lbs-ft) of torque from 3,500 to 5,250 rpm and was an amazing 30 percent more fuel efficient than its predecessor the M272 engine. Some of its main features were:

-  aluminum alloy cylinder block and head;

- third-generation direct injection system with electronically-controlled piezo injectors;

- multi-spark ignition (i.e. multiple ignition events during the combustion stroke);

- chain driven double overhead camshafts with independent intake and exhaust camshaft adjustment; and,

- ECO start/stop system.

The SL350 accelerated from zero to 100 km/h in 5.9 seconds, which made it three tenths of a second faster. While the V6 of the R230 had a 90-degree vee-angle, the M276 power plant came with a 60-degree angle. The 60-degree angle construction had the advantage that no balance shaft was needed anymore, which helped to reduce the engine’s complexity. The V8 M278 engine, which was similar in construction, retained the 90-degree vee-angle.

The V6 has its own unique engine cover design

The V6 included variable camshaft control for the intake and exhaust side of the engine

Like the M272, it had an aluminum engine block and dual overhead camshafts with independent variable valve timing on intake and exhaust valves. But the timing chain arrangement had been revised. As already mentioned before, the direct injection featured, like in the M278 V8, piezo-electrically controlled injectors in order to improve fuel efficiency. A multi-spark ignition allowed for multiple ignition events during each combustion stroke.

In order to reduce parasitic loads, fuel pump, water pump, alternator and oil pump all had to be revised. The parasitic load is a term that represents the power consumed, even when an appliance such as the fuel pump is shut off. Most of the electrical appliances in modern cars are designed to still draw some power/current when switched off. The Bosch MED17.7 engine management offered detailed individual cylinder control, including fuel spray, spark timing and anti-knocking.

However, development did not stop there: magnesium two-stage resonance intake manifold increased the intake runner length at lower rpm for optimized performance and electro-pneumatic turbulence flaps at the start of the intake path increased the airflow speed at midrange rpm for a stronger and more complete combustion. Actually, they did not just increase the airflow, they varied the path and flow of the incoming air. At lower engine speeds, the path was made longer in order to help speed-up the air intake for better cylinder charging. At higher engine speeds, the intake path was shortened in order to maximize the air volume. The engine came with one high-energy ignition coil and spark plug per cylinder.

The author would like to talk in this chapter also about the car’s batteries, as there might be a few questions or uncertainties. The R231 has two batteries. The main one is at the bottom of the trunk, while a smaller motorcycle-size auxiliary battery sits in the compartment behind the passenger seat in a small cage next to a fuse panel. What is it for? Mercedes refers to it as the “ECO start/stop function additional battery". It should prevent a drop in supply voltage when the engine start/stop function is starting the engine again. When the engine starts, all electric loads, except the starter, will be switched over to the aux battery. After the engine runs and the starter has disengaged, all electric loads are transferred back to the SL's main battery.

In case of a dead main battery, the aux battery also powers the "Intelligent servo module for DIRECT SELECT" (transmission gear selector) as well as the "Electronic ignition switch control unit". This should keep the alarm system and key fob response alive.

How to charge the auxiliary battery? Let us assume the car sits idle for a longer time, then it is good practice to connect a CTEK AGM charger to the main jump points under the hood (both batteries are AGM). This will then also charge the small battery. Although it is not really needed, because the aux battery has zero load on it, when the car is turned off. By the way, the author charges his cars’ batteries, whenever they are not been driven for a week or two. He has done that for a couple of years now and he has yet to see a battery failure.

The transmission

Next to the S-class, there are few Mercedes cars that were better suited to an automatic gearbox than the big SL. Long gone were the days of a 230SL, when journalists complained that the pagoda SL could be outfitted with an automatic transmission. Today’s automatic boxes, and here especially the 7G-Tronic unit, shifted much better through the gears than most drivers would ever accomplish.

The 7G Tronic, also known as 722.9 gearbox, made its debut in 2004 and was the fifth generation of Daimler-Benz automatic gearboxes. It replaced the five-speed gearbox 722.6 and was used for two different power classes. With the designation W7A400 it was installed in cars with up to 400Nm of torque input. With the designation W7A700 it shifted gears in cars with up to 700Nm of torque input.

The older 722.6 box was plagued with leaked fluid at the electrical connector, which then made its way into the remotely mounted transmission control unit. With 722.9 this problem was eliminated by placing the control module in the center of the electrohydraulic actuator, where it was completely submerged in the oil fluid.

This way two benefits were achieved: the electrical connector was above the oil fluid level, making possible leaks nonexistent and the submerged control unit could be kept at a more constant temperature.

Like many modern automatic gearboxes, 722.9 was externally programmable, which meant that it could be used for various applications, minimizing the number of different modules. Another benefit was the ability of the DB-dealer to download fixes or patches that would reset or improve performance.

A look inside the 7G-Tronic transmission

The rather complex electro-hydraulically operated control module evaluates gearshifts, activates and adapts eight solenoid valves and calculates gearshift point

An external modification of the gearbox was its housing, which was now made of die-cast magnesium. The advantage was a weight reduction and increased strength of the box. Unfortunately, some disadvantages had to be tolerated too. Magnesium does not work too well in combination with some other metals. Steel is one of them. That is why the old steel bolts had to be replaced with more expensive aluminum bolts. These bolts cannot be used again, once the box is disassembled. New ones have to be used and as aluminum is a softer material, torque specifications have to be carefully observed.

As a traditional torque converter, it provided almost imperceptible gear changes. Calibrated to offer relaxing progress, it usually shifted up early and came with a certain reluctance to kick-down unnecessarily eagerly, which was just fine for most of today’s driving situations. This behavior was also beneficial for overall fuel consumption.

On the other hand, for the more initiated driver, it could also show a completely different character. Because one of its hallmarks was its excellent use of gears, as each gear change had its own set of adaptation data for upshifts and downshifts. Unlike other transmissions, which shifted sequentially through their gears, while up- or downshifting, the 7G-Tronic could skip as many as four gears at a time, which resulted in much faster up/downshifts, coupled with the ability to get back on the power much sooner. This behavior was called driver adaptation and was even more pronounced on AMG models. The control unit understands your driving style and thinks you want to go hit the throttle one more time to get away from it all. That is why it holds the lower gear longer than usual to give you all the power needed in a split second. If no action is taken by you, it assumes that this outburst of adrenaline in you has passed and it switches back to standard shift mode.

By the way, although the paddle-shifts behind the steering wheel were nice add-ons, after having used them for some time because of their novelty, the average driver will soon realize that it was at the end better to let the 7G-Tronic handle the job on hand alone.

The suspension

Part of the rear axle; to optimize weight, most components were built from aluminum

Both the SL350 and SL500/550 were available with a semi-active adjustable damping system with steel springs. It was similar to the one used already in the R230. The system continually adjusted to driving inputs and the road surface, and could respond at each wheel in just ten milliseconds to sharpen handling while the ride remained silky smooth. Comfort and Sport modes let the driver tailor handling response and ride firmness to his/her present driving style. Virtually all components of the 4-wheel multilink suspension were made of rigid, lightweight aluminum.

The air-sprung active suspension system “Active Body Control” ABC (code 487), first seen in 1999 in the then new S-class coupe C215, remained an option. It is not universally liked by Mercedes drivers and if something goes wrong with it, it is usually very expensive to fix. But if properly maintained, it is superb. ABC allows control of the SL body motions and virtually eliminates body roll through an interplay of hydraulic, mechanical and electronic parts by some 68 percent, when compared with a car with conventional suspension. With a push of a button on the center console, passengers could choose between a sporty or comfortable set-up. With the "sport mode" activated, the body roll was reduced by an even more impressive 95 percent.

Once the driver of an SL had the pleasure of experiencing the virtues of this system, he/she would not want to drive such a car anymore without it, as it really made (and still makes) this big car corner “like it is on rails”.

How does it function? The lower elements of the front axle, the steering gear of the rack-and-pinion steering and the engine mounts are all connected with an aluminum frame-type integral support. Four suspension struts, which consist each of an in parallel connected steel coil spring and shock absorber, plus a hydraulically controlled adjusting cylinder, are located between the wheels and the SL body. They have the purpose to adjust the cylinder and change the suspension length in order to keep the car level under all conditions. This is nothing really new though.

Then a total of thirteen sensors monitor body movements and vehicle level. Four of them are level sensors at each wheel, three accelerometer sensors check the vertical body acceleration, one acceleration sensor measures the longitudinal and another one the transverse body acceleration. Each of the four hydraulic cylinders has a pressure sensor to check the hydraulic pressure, which is supplied by a high-pressure radial piston hydraulic pump, located close to the SL’s engine. The thirteen sensors supply the onboard control unit every ten milliseconds with new data. The computer compares the acceleration data with the pressure and level data and translates them into control signals.

These signals are implemented as precisely metered oil flows by hydraulic servo valves, mounted in series on top of the suspension strut beside each wheel. They adjust the suspension to generate counter-forces to body lean, dive or squat during all possible driving maneuvers, resulting in an unparalleled driving experience. The height adjustable function automatically lowers the SL’s suspension by around eleven millimeters at speeds between 60 km/h (37 mph) and 160 km/h (99 mph) for better aerodynamics and in order to improve fuel consumption and handling. It also raises or lowers the SL in response to its respective load.

Stock tire sizes are 255 / 40 on 18 inch rims at the front, and 285 / 35 on 18 inch rims at the rear. For stopping power, the SL350 braking system includes Vented Discs at the front and Vented Discs at the rear.

Steering of the R231 was of the rack-and-pinion type with an electro-mechanical “Direct-Steer”-system. It was derived from the previous speed-sensitive power steering that Mercedes-Benz had offered for many of its models. With this concept, the power that had to be exerted to steer depended on the vehicle's speed. As the speed rose, so did the steering effort. In practice, this meant low, comfortable steering forces when performing parking maneuvers on the one hand, and high safety when driving fast with increased steering forces for assured straight-line stability on the other.

Added to this was a variable steering ratio, which changed depending on the steering angle. In and around the central position, the steering had an indirect ratio for excellent straight-line stability, meaning a high level of handling safety. The direct-steer system's ratio started to increase very rapidly at a steering angle of just five degrees, and felt quite direct from a steering angle of around 100 degrees. The result was a reduction in the required steering angle. In other words, relatively small turns of the wheel are all that was needed to direct the SL, virtually eliminating the need to reposition the hands, even on tight bends. Fast sequences of bends could be negotiated almost intuitively with relatively small steering movements, as the number of steering-wheel turns from lock to lock was reduced by around 25 percent.

At the core of the system was nothing more than a simple steering rack. Its secret lied in the gearing impressed onto it. In the middle, it appeared to be slightly undulating with changing flanks, towards each side it took the form of teeth spaced at varying distances. Consequently, the change in steering ratio was achieved by mechanical means alone. Thanks to this, the engineers were able to dispense with the elaborate actuator units and complex sensor systems needed for other variable-ratio steering systems. This meant this direct-steer system will be less susceptible to faults and on top it was lighter than these systems too.

Wheel angle with and without direct steering

The Direct-Steer system, improved handling and agility, while also reducing physical effort when parking

Weight saving was high on the list of the engineers. One of the many options was the trunk lid. Its interior support consisted now of a light, yet extremely rigid carbon-fiber composite material, which was bonded to an equally light plastic outer shell. This resulted in weight savings of five kilograms in comparison to a conventional trunk lid

Prices and Edition 1 model

While the SL350 cost from €93,534 ($123,460) onwards, prices for the SL500 started at €117,096 ($154,570) in Germany, both prices included 19 percent VAT. Prices in the UK started at £71,525 for the SL350, while the SL500 cost around £82,200.

In the US, the SL350 was again not available, prices for the SL550 started at $105,500. Should you have fancied the Premium 1 Package at €3,712 ($4,900), it would add a rearview camera, Parktronic with Active Park Assist, ventilated multi-contour seats, the Airscarf, power trunk closer and Keyless Go.

The engine start button for the Keyless Go option was moved from the gearshift knob to the dashboard. You could have the analog clock on the dash in Porsche 911 fashion for €190 ($250), Magic Sky Control for €1,890 ($2,500) and Active Body Control for €3,100 ($4,090). A Driver Assistance Package for €2,235 ($2,950) included Distronic Plus with Pre Safe Brake, Active Blind Spot Assist and Active Lane Keeping Assist.

The clock on top of the dashboard could be yours for €190

In order to further enhance the interest in the new SL, Daimler-Benz offered for the first time directly

from the start a “Special Edition” model, called “Edition 1”

The “Edition 1” model was available for all engines, including the SL63

Depending on the standard model, the “Edition 1” cost between €19,028 and €22,598 ($25,120 to $29,830) extra and offered the panoramic roof, various Edition 1 badges, AMG body styling, sports suspension, special AMG 19-inch wheels and designo crystal sliver magno paint. Inside it featureed designo red Nappa leather with contrasting stitching, Airscarf, heated seats, electric draught stop, ambient lighting and a special Harman Kardon Logic7 surround sound system would be a delight for the audiophile owner, now that the SL featured the “FrontBass” system.

No new SL would start without making reference to the one and only

Then it continues: “Six decades of breakthroughs later, the 2013 SL-Class reaffirms its sporting roots-with advanced performance engineering enveloped within an all-new aluminum body, a first for an SL. It is lighter and more powerful, for quickness and agility. Yet it is stronger and more efficient, for remarkable civility. Simply put, it is designed to conquer the open road like never before. And capture your heart as only an SL can.”

“Car and Driver” tested an SL550 in September 2012:

“Every move the 2013 SL550 makes is steeped in a competent, laid-back confidence; pin the throttle, and the car takes a moment to gather itself, as if saying to the driver, “Okay, dude, you ready? This is gonna be pretty awesome.” And with that, the seven-speed automatic downshifts, the twin turbos gorge themselves on air, and the whole shebang takes off, pulling hard to an observed 159-mph top speed (Mercedes claims an electronically limited 155)…

…With a 429-hp, 4.7-liter twin-turbo V-8 lurking beneath its hood, our 4138-pound SL550 posted some impressive acceleration numbers, taking only 4.1 seconds from 0 to 60 and knocking down the quarter in 12.5 seconds. Not bad, but a brutish, naturally aspirated 2013 Chevrolet Corvette 427 convertible (pushrods, the shame!) we tested trumped the SL on both counts at 3.9 and 12.2 seconds, while ringing in for about $30,000 less than the SL’s $106,405 base price.

Of course, you’ll sacrifice the SL’s slick, folding hardtop, weight-shaving aluminum unibody, and luxurious interior trappings for the Vette’s canvas softtop and fiberglass carcass in the bargain, but in the narrow segment of front-engined, V-8–powered, two-seat convertibles, you take the comparisons where you can find them…

…Where the SL really shines is in delivering lavish refinement and undiluted, hedonistic bliss, numbers be damned. It doesn’t matter if you’re in New York, Monaco, or Topeka; after a day of top-down cruising with the A/C and ventilated seats running at full chill, you’ll feel like a Hollywood player. As such, feel free to drop by Hef’s place and grab some face time with Kanye in the grotto while Jonah Hill reels off another round of wacky bar mitzvah stories. This car may be German, but it speaks the international language of wealth fluently.”

And they concluded:

HIGHS

Poise and capability, weather-tight folding hardtop, storied lineage.

LOWS

Hefty price, inelegant styling, numbish steering.

In the UK, “Auto Express” tested in August 2012 an SL350 and actually recommended it over the SL500:

“While the SL500 has a 429bhp 4.4-litre twin-turbo V8, the SL350 is powered by a 3.5-litre V6 with 302bhp, so you sacrifice a bit of performance. Officially, the 350 covers 0-62mph in 5.9 seconds – the 500 does it in 4.6 seconds – but it feels punchy and instantly responsive.

The SL350 also feels more like a sports car, encouraging you to use the whole rev range, rather than the effortless and almost lazy low-rev punch of the SL500’s engine. Take a look at the figures and it’s easy to see why. The V8 delivers 700Nm of torque from 1,800rpm, while the SL350 has just 370Nm from 3,500rpm. And although the V6 doesn’t offer the V8’s menacing roar, it still makes a nice, understated growl.

There are also a few subtle differences in the way this car handles. While the quick steering in the SL500 always seems to be offset a little by the car’s sheer weight, the SL350 – which is 100 kg lighter – feels eager to dart into bends with real agility. In every other way, though, this cheaper SL feels identical to more expensive models in the range, so that means a luxurious ride and excellent refinement.

And you can also add lower running costs to the SL350’s list of talents. It’s 140kg lighter than the car it replaces, which helps it return 37.7mpg and emit 169g/km of CO2. In comparison, the SL500 claims 30.7mpg and 212g/km. Both models are equipped with stop-start, but the system works more seamlessly in the V6, cutting the engine smoothly and firing it up again almost instantly.

The SL350 scores with its sharper handling and more frantic V6. So if you’re in the market for a new SL, we’d say cheaper is definitely better. As long as you can put up with the slower 0-62mph time, the SL350 has plenty of benefits over its muscular, V8-engined brother.”

The 2-seat roadster was at its best visually with the top down. Then the high rear deck needed to stow the metal and glass canopy became somewhat less obvious

The up side of the prodigious rear end was that you got a 504-liter trunk that only shrank to 364 liters if you wanted to fold the canopy. It was easily big enough for a weekend’s worth of luggage – much more if you kept the roof up.

“INTELLIGENT LIGHT” let the headlights swivel 15 degrees each way, every time the steering wheel was turned, lighting your way around corners. The infinitely variable intensity of the headlights lit the road to maximum distance ahead without blinding drivers of oncoming cars

The whole roof opening or closing operation could be done in 20 seconds

The R231 and its predecessors (this comparison looks definitely better in the printed version of this e-book)

The SL63 AMG

There are plenty of discussions on the internet about what constitutes an AMG model. Daimler AG sold and sells AMG Sport Packages or body kits for almost any of their models. This makes it difficult for many to distinguish between a real AMG and an AMG look-alike. Also on the second-hand market, cars with the Sport Package are sometimes advertised as Mercedes AMG cars. But true AMG cars are distinguished by what is under the hood. All AMG power plants (except R129 and some SLK versions) have a silver engine cover with the name of the technician, who built that very engine, proudly displayed on top of it with a plate.

AMG was founded by Hans Werner Aufrecht and Erhard Melcher in June 1967 as a racing shop. As with many other companies, the first two characters were borrowed from the last names of the two founders. The third character “G” in the AMG name did not come from the company’s first location, but from Aufrecht’s place of birth “Großaspach”. Both gentlemen were former Daimler-Benz technicians, who offered initially engine performance packages and various unofficial upgrades and accessory packages for Daimler-Benz cars. Daimler-Benz engineers used to laugh at them due to their tiny business size.

They also did not take them too seriously because of their continuous underfunding problems. But over the years AMG managed to mature into a full-fledged racing company with its first major rally success in 1971. In that year they managed to score second overall place behind a Ford Capri at the 24 hours race at Spa with their impressive 300SEL 6.3, called “Red Sow”. The 6.3 was actually a 6.8 and it won first place in its class. In 1990, AMG signed a cooperation agreement with Daimler-Benz and in January 1999, Daimler-Benz acquired 51 percent of the company. At that time, the name was changed into Mercedes-AMG GmbH (Ltd.). Since January 2005, AMG is a wholly owned subsidiary of Daimler AG. The first official model developed by AMG in 1991 was the AMG 500SL 6.0 V8 (M 119) R129 with Bosch KE injection, 374 hp at 5.500 rpm and a maximum torque of 550 Nm (405.7 ft-lbs) at 4.000 rpm.

Erhard Melcher in the very early AMG days

On February 21st 2012 the SL63 had its sneak preview in Spain and was tested by F1 drivers Michael Schumacher and Nico Rosberg at the Formula One race course Circuit de Catalunya in Barcelona.

The car was introduced to the public at the annual Geneva Automobile Show in March 2012 with first cars to become available in Europe in May. First regular shipments to the UK and US started in June of that year. When the first SL63 arrived in the US, it was given away as 1st price at the 6th annual auction of the Florida Boca Raton Concours d’Elegance Gala.

The new model was distinguished from the standard SL by a more aggressive front design and it was some 125 kg (275 lbs) lighter than its predecessor. Prices for the SL63 started in Germany at €159,400 and for an additional €14,400 one could opt for the Performance Package. It included red painted brake calipers, a top speed of 300 km/h (186 mph), AMG steering wheel, limited slip differential, a power increase from 537 hp and 800 Nm to 564 hp and 900 Nm, plus a carbon fiber engine cover and trunk-lid spoiler.

If the prospective owner wanted to upgrade his SL63 further, he/she could choose the Carbon Ceramic Braking System for €9,780. Another €1,300 would give him the wheel package, which came with 10-spoke AMG staggered wheels. Packages that were available for the standard SL, were also available for the AMG version. Adding it all up, the potential owner could easily spend some €210,000 for a truly magnificent, fully equipped car. Prices in the UK started at £109,275, while the car cost in the US from $145,800 upwards.

A price conscious prospective SL buyer could of course say that in its essence, the SL63 remained an SL, and an SL350 with AMG sport package would not look that much different. But then this person did not understand the true meaning and emotional value of AMG.

The SL63 at the 2012 Cannes Film Festival in Southern France

Technical aspects

The old naturally aspirated 6.2 L (378.3 cu in) M156 V8 engine, which had replaced in 2008 the much-loved SL55 engine, was history and had been replaced for the new model by a twin-turbo M157 V8 with 5.461 cc (333.3 cu in) displacement (internal code: M157 DE55 AL). It offered a bore of 98.0 mm and a stroke of 90.5 mm.

The parallel twin turbocharge design used one turbo for each bank of cylinders, with both of them running all the time. The purpose for this layout was the reduction of piping that was required for the plumbing of the intake and exhaust systems, which would increase response time and at the same time reduce the turbo lag. Parallel twin turbos are smaller in size in order to achieve said quick response times. The smaller size had one downside though: due to it there was less exhaust gas available for each turbo, which limited somewhat their high-end power delivery and boost potential.

The power plant, which was offered across the Mercedes range of cars with a “63” denomination, delivered in the SL63 530 hp at 5,500 rpm and a maximum torque of 800 Nm (590 lbs-ft) between 2,000 and 4,500 rpm. The old R230 SL63 naturally aspirated power plant delivered 525 hp at a much higher 6,800 rpm and offered a maximum torque of “only” 639 NM (463 ft-lbs) at 5.200 rpm.

The new twin-turbo 5.5 l engine had a bore of 98.0 mm and a stroke of 90.5 mm

So, the new SL63 was not only SL55 territory again (720 NM or 530 ft-lbs), it was in fact much better. The massive torque the twin turbos are capable of producing at low rev needs to be experienced to be believed. The increase in power and torque did not only come from the increased displacement, it also came from the boost pressure, which was increased from 0.9 to 1.0 bar.

With the performance package the power went up, as already mentioned, to 557 hp at 5,500 rpm and 900 Nm (664 lbs-ft) from a slightly higher 2,250 rpm. The engine came with an all-aluminum block, spray guided direct injection, valves with variable valve timing and air/water inter-cooling. The weight optimized AMG (minus 125 kg or 275 lbs) had an ECO start/stop system and an amazing thirty percent better gas mileage than its predecessor. Exciting times and although the turbochargers damp the sound somewhat, the car still barks and bellows like a NASCAR race car, especially with the pedal pushed to the metal.

While the SL63 accelerated in 4.3 seconds (Perf. Pack.: 4.2 seconds) from zero to 100 km/h, it could reach 200 km/h in 12.9 seconds (Perf. Pack.: 12.6 seconds). Top speed was as before electronically limited to 250 km/h or 155 mph (Perf. Pack.: 300 km/h or 186 mph). Its 10mm lowered sport suspension was based on the Active Body Control ABC, but tweaked with a focus on driving dynamics and performance. The driver could switch between “Sport” for reduced body roll and firmer shock damping and “Comfort” for a slightly softer shock damping. For faster cornering speed the car had now more negative camber all round and improved elasto-kinematics.

By the way, no SL exported to the US featured the lowered sport suspension, possibly due to DOT issues. Mercedes-Benz had offered the lowered suspension elsewhere since 2012 anytime when customers opted for the AMG package.

The SPEEDSHIFT MCT 7-speed sports transmission was already available in the R230 and had been adapted to the new engine. MCT stood for Multi Clutch Technology, which meant it moved off with a wet start-up clutch instead of a torque converter. Offering four shift modes and a double-clutching function, it guaranteed a high level of versatility and fast shift times.

The MCT’s four drive modes: "C" (Controlled Efficiency), "S" (Sport), "S+" (Sport plus) and "M" (Manual) provided customized shift control and maximum driving pleasure. In “C” mode the ECO start/stop function was permanently active and turned off the engine, when the car had stopped. Throttle response and shifts in comfort mode were also “softer”, while in S mode shifts were faster and the clutches bit quicker. Shifts were approximately twenty percent faster than in Comfort mode, and for a further twenty percent speed improvement, you could use S+. Using M mode, a further 10 percent was cut down for a total of fifty percent over the C mode – shifts only took 100 milliseconds in the M mode.

As an option, the steering wheel was flattened at its upper and lower side

The AMG Speedshift MCT7 came with a different gearshift console

Downshifts in S, S+ and M modes used precise double-declutching and could jump multiple gears, straight from 7th down to 3rd for example, just like the standard 7G Tronic. This gave the drive a sportier feel as the engine and exhaust sounded really great during double declutching. It also served to minimize load-change reactions during downshifts.

The sound that leaves these exhaust pipes is pure music to any enthusiast’s ears

The gearbox also had a Race Start function (launch control). It was basically a way to get off the starting line with maximum acceleration, and -- race drivers might not really appreciate this -- everything including optimum launch revs, the launch itself, and then subsequent shifts were taken care of, all the way to top speed.

The newly developed compound brake system had 390x36 mm (15.3x1.42 in) discs with six-piston fixed calipers at the front and 360x26 mm (14.2x1.02 in) integral discs with single-piston floating calipers at the rear. Optionally available were red-painted calipers and a ceramic high-performance brake system, which was similar to the one on the SLS.

The car rode on five-twin-spoke alloy wheels painted in high-gloss titanium grey with 255/35 R 19 tires at the front and 285/30 R 19 at the rear.

As an option multi-spoke forged wheels with 255/35 R 19 tires at the front and 285/30 R 20 tires at the rear were available. They too came in high-gloss titanium grey, but could also be painted in matte black with the rim flange in a contrasting silver finish. This looked especially good with the optional red AMG calipers.

The Performance Package included next to the higher power output and top speed a Performance steering wheel with DINAMICA side grips, a limited slip differential lock and the red brake calipers. From June 2014 onwards, the power output was increased from 564 hp to 585 hp. Torque remained at 900Nm. With this change, the differential lock would form part of the standard scope of equipment.

Optional “Performance” steering wheel with DINAMICA side grips (below is the standard AMG wheel)

Another SL63 at the 2012 Cannes Film-Festival

Body and interior

As already said before, the AMG models had their unique body styling, which included a special front apron with an increased air dam to help keep the engine cool. The apron offered AMG-specific LED daytime running lights in a chrome frame. “V8 Biturbo” badges could be found on both sides of the panels next to the air vents. At the rear, you could find a spoiler lip and the typical chromed twin tailpipes with the AMG logo. However, it did not stop there. The new SL63 was the first car to feature the reinterpreted “AMG brand face”.

The two most dominant elements in a car’s front are the radiator grille and the lower cooling air intake. The new AMG brand face gave them a more distinctive identity in terms of dynamism and perceived value. The iconic Mercedes SL star in the center of the grille was now accompanied on both sides by two high-sheen blade like louvers or shafts, whose thin profile gave them the form of an aircraft wing.

The lower cross strut of the more pronounced apron was also finished in high-sheen chrome and served as a complimentary styling element to the twin blade grille. These two features would be introduced to all AMG models in order to add greater emphasis to their appearance.

The new SL AMG front apron (above) compared with the standard SL (below)

The interior offered very comfortable and supportive multi-contour sports seats in single-tone or two-tone Nappa leather with the typical AMG upholstery design and AMG badges in the seat backrests.

The IWC clock was an AMG exclusive and not available for the other models

The doorsill panels were again illuminated with ambient lighting and optional AMG carbon fiber trim, a special IWC analogue clock plus the typical AMG performance steering wheel made the interior stand-out from the normal SL. The instrument cluster provided the usual AMG information including a start-up display and race-timer. Other standard equipment items were Attention Assist, Harman Kardon Logic7 surround sound system, remote-unlocking trunk lid with power closing function, Neck-Pro head restraints, Pre-Safe and power wind blocker.

The AMG part of the R231 brochure promoted again the “One man, one engine” philosophy

The “Edition 1” package offered similar goodies as in the standard SL, one could choose between an interior in classic-red or designo classic white with contrasting stitching. Also, the roof lining was covered with leather. The AMG Edition 1 version would be delivered in two matte colors: magno black or designo magno brilliant silver. The equally optionally available “designo” package was again available with various single and two-tone leather interiors.

Motortrend tested the SL63 in May 2013:

“Compared to the 429-horsepower SL550 we tested almost a year ago, the 2-pound-heavier SL63 AMG is a half-second quicker to 60 mph from a standstill (3.5 seconds) and stops 3 feet shorter from the same speed (102 versus 105 feet). With the massive 285/30R-20 rear Continentals warmed to their optimum operating levels, our hot-shoe Scott Mortara saw a quarter-mile in 11.8 seconds at 123 mph, some 0.7 second and 9 mph quicker than the 550. Grip levels, as you can imagine, improved as well. Average lateral acceleration is now 0.97 g versus the base car’s 0.94 g best.

Just four years ago, such athleticism would have meant the V-12-powered Black Series treatment. The 63’s sprints to 60 mph and through the quarter-mile are nearly dead even with those of the 2010 SL65 AMG Black Series Coupe, a fixed-roof monster packing 661 horsepower from a twin-turbo V-12. Its braking, figure-eight, and lateral acceleration numbers are better than the $300,000 limited edition as well.

One key observation: Gathering handling data in the SL63 wasn’t point-and-shoot easy. Like that prohibitively expensive Black Series, this SL is a lot to handle when driven hard with its many electronic nannies disabled. In fact, we wouldn’t advise turning them off at all unless you’re a professional driver, an extremely skilled average Joe, and/or a majority stakeholder in a premium tire company…

…Turbo torque is ubiquitously available. The full cache of thrust can be accessed at an unbelievably low 2000 rpm. With seven nicely spaced gear ratios, there is no uncomfortable search for the proper cog when a stroll becomes a sprint. Want to pass that slower SUV, you say? Feed TORQV8R a smidge more throttle to glide by. He doesn’t mind one bit.

Nor does he mind hard charges on backcountry roads. A run up and down San Diego’s Palomar Mountain not only showcased the AMG-assembled powertrain’s smoothness and veracity, but also the adeptness and civility of the massive six-piston 15.4-inch front/14.2-inch rear brakes and AMG-tuned Active Body Control (ABC) adjustable suspension.

The binders annihilated momentum as awesomely and confidently as the 5.5-liter twin-turbo that created it. ABC shored up damping enough to reduce the SL’s pitch and roll on Palomar’s sharp and sweeping corners to nearly nil degrees. I tip my hat to AMG’s development team: Their SL withstood the full brunt of my two-hour mountain ascent and descent on a blistering 85-degree day without fault, not to mention an additional two week’s worth of hard miles at the hands of other MT staffers.

Nobody truly needs 664 lb-ft of torque. Not the hedge fund manager, not the young entrepreneur, not the Hollywood actress with loads of expendable cash, not even the most fanatical automotive maven who understands the basics of high-performance driving. But it’s not the torque that creates the siren call – it’s that three-character badge, that solid build quality, that fresh exclusivity, that easy speed, that sexy style, that cushy cabin, that iconic Affalterbach rumble. They’re all extraordinary traits that feed the discerning egos who crave the feeling of specialness, and who will likely make the twin-turbo 63 their next plausible plaything.

So go ahead and thank your closest moneyed neighbor, for if they and the impetus they’ve created didn’t exist, we wouldn’t have such a remarkable, uber-refined, stratospherically powered, phonically well-endowed, tech-jammed, 25-mpg-on-the-highway grand touring athlete to appreciate.”

The SL65 AMG

Given the poor sales of the previous V12 AMG model, it came a bit as a pleasant surprise, when Daimler-Benz announced early 2012 that next to the SL63 AMG a V12 SL65 AMG would be introduced too. AMG was certainly aware that this powerhouse would not sell in large numbers. But as both the engine and the new SL body were already available, it can be safely assumed that development costs were at a reasonable level for a car that was sold at a premium. And its new proud owners were in their majority not after that little bit of additional power. They would appreciate that they drove the only V12 sports car that Daimler-Benz had on offer, now that the SL600 was gone.

The SL65 was available in Germany since September 2012 and cost €236,334, incl. 19 percent VAT ($314,850). In the US and the UK the big SL could be purchased since early 2013 at a base price of $212,740 (USA) and £168,285 (UK) respectively.

Germans like to remove all badges from their monster cars

Anyone who does not consider the automobile to be the nail in the coffin of humanity, who perhaps even feels comfortable in a world beyond reduced fuel consumption and autonomous driving, will not be left untouched, when a Mercedes-AMG model fills his/her field of vision. The enthusiast awaits with a certain eagerness the burst of the V8 engine, be it the old 6.2-liter naturally aspirated or the 5.5-liter biturbo. As soon as the first chunks of bass plop out of the characteristically angular exhaust, fans quickly conclude: "That is just what an eight-cylinder has to sound like."

So how does the V12 biturbo of the SL65 from the same manufacturer sound? Well, instead of bubbling magma, the six-liter unit sounds more like frothy boiling milk, if that expression is allowed. It remains surprisingly discreet, rumbles rather than shouts, and makes itself quite unsuspicious with its massive 630 hp output and insane 1,000 Newton meters of torque - which is already available at 2,300 rpm.

But, switch the AMG button to Sport or Sport+ mode, whir the roof back into the trunk and you will be able to hear the V12’s smooth, now slightly aggressive, engine note a little better. But driving in the most aggressive mode, though, you get the impression that this beast is not really suited to B-road blasts – it is heavy, at over two tons with a passenger on board. Yet, if you leave twisty roads to others and switch the SL back to its comfort setting, there are few better long-distance cruisers. At 110 km/h (68 mph), the engine whispers along at slightly below 1,700rpm, yet instant, almost brutal acceleration is just a flex of your foot away. Wind and tire noise are very well suppressed and the seats are extremely comfortable.

Technical aspects

The 5.980 cc (365 cu in) V12 twin-turbocharged M279 engine (internal code: M279 KE60 AL) was based on the previous R230 SL65 M275. It was an intercooled, all-aluminum 60-vee angle V12 with single overhead camshaft, three valves per cylinder and twin-spark ignition lay-out. Both engines were loosely based on the naturally aspirated M137 V12 engine, which was offered between 1998 and 2002. It used the same parallel twin turbocharge design like the SL63 with one turbo for each bank of cylinders, both of them running all the time. It meant that it also suffered in theory from limited high rpm power. An alternative could have been a sequential turbocharger with one small and one larger unit to cope with all rpm situations more successfully.

Mazda had such a set-up in their RX7. However, they tend to be less reliable and on top more difficult to maintain. And as the V12 had due to its size more than sufficient power and was most likely not used for extensive high-speed chasings, this small drawback was seen by Mercedes engineers during development time as negligible. The M279 turbochargers used an increased spiral cross-section and the engine came with revised wastegate ducts and redesigned exhaust manifolds. The cylinder heads had been altered to optimize flow characteristics, new forged pistons and forged crankshaft were made of high-grade quenched, tempered steel.

Hollow-stem outlet valves were filled with sodium and the low-temperature cooling water circulation came with a separate expansion reservoir. In order to have the engine run ultra-smooth under all driving conditions, it received a new multi-spark ignition with 12 double ignition coils.

In combination with a revised electronic engine management this resulted in a more effective combustion, which in turn made the engine quieter. Not that this was desperately needed, as the old V12 power plant was not known for unruly behavior under full load, but it shows the determination of the AMG engineers, who were now in charge of all V12 developments, to further improve their already convincing package. As already mentioned earlier, the upgraded power plant developed 630 hp (R230 SL65: 612 hp) at 4,800 rpm and its impressive torque of 1,000 Nm (738 lbs-ft) was available between 2,300 and 4,300 rpm.

With a curb weight of 1,950 kg (4,299 lbs), the new car was 170 kg (375 lbs) lighter than its predecessor and used some 2.4 l less fuel, which was a saving of 17 percent. It accelerated in 4.0 seconds from zero to 100 km/h and achieved an electronically limited top speed of 250 km/h (155 mph) that could be extended on special request to 300 km/h (186 mph) For some markets like the US for example, the speed limit was standard already 186 mph. All this showed that when you sit behind a V12 engine, there was nothing to worry about a possible lack of power, especially, when this engine came from AMG.

Push the accelerator pedal to the metal, and the big car gets tangled up in the claws of the sophisticated ESP electronics pretty quickly - and those who switch it off get tangled up in the surrounding botany just as quickly. But it is precisely these bits and bytes that help the two-seater to storm forward under the poisonous growl of its two turbochargers, missing the factory specification from zero to 100 km/h by a paltry tenth of a second only.

200 km/h? The question alone could get the enthusiast exited. The SL65 needs only 11.6 seconds for that. Do that a few times, and it will take you days before the diamond pattern of the standard Nappa leather seats disappears from your back. From the very first meter, this pressure settles on your stomach, massaging the force of the engine gently but relentlessly into you, thus demonstrating its power - at the latest when the needle of the tachometer runs over the 2,000 rpm mark, only to tick off 6,000 revs just a moment later. All of this sounds most impressive, yet the SL65 was not any faster than the Performance-package-equipped 557 hp SL63, and that car cost roughly €59,000 less.

Also not to 100 km/h, because at 4.0 seconds, the SL65 is a tenth slower. And not through the quarter mile, both were equal at 11.8 seconds at 200 km/h (124 mph), and not in top speed. Both cars are governed to 300 km/h (186 mph). In passing maneuvers, the SL65 was actually four-tenths slower than the SL63 from 50 to 80 km/h (32 to 50 mph) and a half-second slower from 80 to 110 km/h (50 to 68 mph). The reason for this “lack” of Über-performance was two-fold: first the SL63 had a launch-control system, which the V12 did not have and second, although both cars used the same seven forward-gear ratios in their transmissions, the SL65 had a conventional torque converter between its gears and the engine, while the SL63 was equipped with a wet-clutch arrangement that delivered a hair-trigger response.

For the owners of the SL65, all of this did not really matter. They simply wanted the V12, a car that most others could not afford. Would a more extroverted SLS AMG GT not be the better car for them? Probably not, it was not only some €5,500 ($6,000) cheaper, it also had 38 horsepower less!

The SL65 had a special 7G Tronic transmission with torque converter

Past Daimler-Benz V12 engines had always been mated to a five-speed automatic transmission, which was originally developed for Maybach engines, as the more modern seven-speed alternatives could not handle the sheer amount of torque. Again, customers did not really complain about the lack of two additional gears, as the torque was quite capable to make up for it. It was very much like the good old big-block US V8 engines, which were mated to an automatic two- or three-shifter. The torque was so dramatic that nobody really missed one or two more gears. However, AMG felt that a new transmission would not only result in an even smoother overall operation, more importantly it would help to save fuel.

The new AMG SPEEDSHIFT PLUS TCT 7G-TRONIC would offer the customer a wider gear ratio spread, which in turn allowed a significantly lower engine speed, resulting in the aforementioned lower fuel consumption. The word TCT stood for "Torque Converter Technology" (in contrast to the SL63’s MCT or "Multi Clutch Technology"). However, it was not only the adding of two gears that helped, a new fuel economy converter had been added, bearings were revised for reduced friction and the transmission oil thermal management was upgraded. The dynamic character of the transmission was enhanced by the automatic double-declutching function during downshifts and through the brief, precisely defined interruption of ignition and fuel injection during up-shifts under full load.

This had the additional benefit of reducing the shift times. Also here the ECO start/stop function was activated, when the driver had engaged “C” mode. Despite the significant technical advances, the 7G-TRONIC transmission was barely any larger or heavier than the five-speed automatic transmission. Credit for this impressive achievement went in particular to the transmission casing, which was constructed in lightweight magnesium. As already mentioned, the SL65 transmission lacked the race-start function of the V8 model.

The newly developed compound brake system, introduced already in the SL63, was deemed strong enough to cope with the additional power of the V12 and received no further modifications. Red-colored calipers and the even more powerful carbon ceramic brake system were again available as an option. Also the tires were identical with the ones of the SL63.

The brake system was very easy to control and still had a powerful bite even after several laps on the race course. The copper-colored calipers reveal the system to be the €8,270 option with carbon ceramic discs, but at a base price of €236,334, the extra costs hardly mattered

Body and interior

As expected, design and equipment presented themselves in an exclusive manner: the "twin blade" radiator grille with two blade-shaped louvers and the stylized "A" placed below it, complemented each other perfectly with the lower cross strut in the front apron in high-gloss chrome. Typical V12 features included not only the two chrome-plated, independent twin tailpipes of the AMG sports exhaust system, but also the V12 BITURBO lettering on the fenders.

Inside, the SL65 had exclusive design and equipment features which differentiated it from its V8 sister model. The electrically adjustable AMG sports seats with single or two-tone upholstery in Nappa leather with a special AMG diamond pattern were a particular highlight. This distinctive upholstery was also to be found on the door center panels. Embossed AMG emblems on the seat backrests were standard, as were AirScarf neck-level heating, multi-contour functionality, seat memory and climatized seats. The designo headlining in leather with partial AMG V12 diamond-design quilting provided the perfect visual and tactile finishing touch.

Like in the SL63, the speedometer was calibrated to 360 km/h or 220 mph and the start-up display showed a V12 Biturbo animation. The car came almost fully equipped with goodies, which were only available as option for the SL63: the fantastic Bang&Olufsen BeoSound surround system, Comand Online with 6-disc DVD changer, Convenience telephony, Keyless-Go with Hands-Free Access system. On top the SL65 owner could choose between the panoramic vario roof and the one with Magic Sky Control.

Both AMG cars shared the same interior equipment, only the seat design of the V12 differed

Naturally, the car could be ordered in numerous paints to match the owner’s taste. Many of them came along with fairly colorful names such as “designo magno cashmere white” or “designo magno alanite grey” to name just two. Or how about an early evening cruise along Sunset Boulevard in Miami in a “designo zircon red” SL? To top it off, there was a range of designo leather appointments in eight attractive colors to match these paint finishes. All was rounded off perfectly by a choice of designo trim, headlining and seat-belt options.

SL65, 45th Anniversary Edition

The streets of automotive history are littered with tuning companies that were created on a great idea, an abundance of enthusiasm, backed by a solid lack of financial funding. When AMG was founded in 1967 by two former Daimler-Benz employees Hans-Werner Aufrecht and Erhard Melcher, they were no different. Daimler-Benz engineers regarded them as rookies and paid very little respect to their achievements. That changed in 1971, when their 300SEL 6.8, the famous “red sow” managed to secure first in class and second place overall at the 24-hour race in Spa, Belgium right behind a Ford Capri.

Most of AMG’s competitors fill today the last pages of automotive history books and it can be credited to the perseverance and ingenuity of the AMG team that they are now part of the Mercedes-Benz conglomerate, in charge of the icing on the Mercedes cake. In order to celebrate the occasion of AMG’s 45th anniversary in June 2012, AMG’s CEO Ola Källenius (who happens to be today CEO of Mercedes-Benz) introduced during the Mercedes press conference on April 4th 2012 at the New York International Auto Show not only the new SL65, but also a limited edition of that car, called SL65 45th Anniversary Edition. This anniversary edition was as P28 Package exactly 45 times available.

An exterior carbon fiber package with a satin finish was exclusive to this edition. It included the cross strut in the front apron, the exterior mirrors and the spoiler lip on the trunk. The sports exhaust system was tuned to provide a characteristic V12 engine sound and the outer surround of the twin tailpipe came in black with chrome plating. The inner insert was finished in high-gloss chrome. The Performance Studio alloy wheels were painted in titanium grey and had a high-sheen rim flange. They carried 255/35 R 19 tires at the front and 285/30 R 20 tires at the rear.

The normally chromed cross strut features now a satin carbon fiber design

The interior was matched to the paint, so the exclusive Nappa leather came in a two-tone titanium grey/ginger beige with a diamond pattern, also the roof was lined with the same leather in ginger beige. The Performance steering wheel featured the AMG logo in its bottom bezel and its rim was covered in two-tone leather. All trim elements were finished in matte carbon fiber and the ashtray featured a special “AMG 45th Anniversary – 1 of 45” badge.

The outer surround of the tailpipes came in black with chrome plating

Almost all extras, such as Comand Online, media interface, Bang&Olufsen high-end surround, Keyless-Go, Magic Vision, Magic Sky, ceramic brakes, Intelligent Light System, Active Park Assist, Parktronic, Airscarf or Pre-Safe and Neck-Pro, to name just a few, came as standard equipment. This edition was launched together with the standard SL65 in October 2012 and cost in Germany €272,034 including VAT. In the US, the price was some $240,000 including $1,300 gas guzzler charge.

The wheels were painted in titanium grey and had a high-sheen rim flange

As before the exhaust tips featured the AMG logo

As did the steering wheel

Even the seats had the AMG logo (here the SL65)

The SL400 replaced the SL350

In the second quarter of 2014 Mercedes-Benz decided it was time to replace the engine of the SL350. And with its passing went the last bastion of Mercedes-Benz naming logic, for the SL350’s naturally aspirated 3.5-liter V6 had not been replaced with a 4.0-litre engine, but a 3.0-litre V6 with twin turbochargers. Mercedes called them bi-turbos. The SL400 retained the 350’s M276 V6, with the internal engine code changing from M276 DE35 to M276 DE30 AL. The new power plant had a capacity of 2996 cc with 88.0 mm bores and an 82.1 mm stroke (SL350: 3498 cc with 92.9 mm bores and an 86.0 mm stroke).

The compression ratio was lowered from 12.1:1 to 10.7:1. What the engine had lost in displacement, it made up for it with power – 26 extra horses to now 328 hp and 81 extra lbs ft to 354 lbs ft. This allowed the car to cut the zero to 100 km/h time by a noteworthy seven tenths to 5.2 seconds. There was no wince-inducing launch control, just a scramble of wheelspin and the SL400 disappeared. The updated V6 engine, which was still mated to the 7G Tronic automatic, was first released in 2013 in the E400 sedan. It had an IHI turbocharger fitted to each cylinder bank, which provided peak boost pressure of 1.8 bar (26.1 psi).

Unsurprisingly, a slight fall in fuel economy, from 7.3 l/100 km (32.2 mpg) to 7.8 l/100 km (30.1 mpg) (NEDC combined), and an increase in combined CO2 emissions, from 159 g/km to 172 g/km, was not mentioned in the press release. Although, to be fair, even the new figures were pretty good for a two-seat roadster weighing 1,730kg.

The new engine had as before an aluminum alloy crankcase, but the cast-iron cylinder liners were replaced by a so-called “Nanoslide” cylinder wall coating. Based on an iron-carbon alloy, the Nanoslide carbon was applied through twin-wire arc spraying (TWAS). Since this kind of coating produced a microporous surface for the cylinder walls, effective lubrication was achieved without the need for cast-iron cylinder liners. Mercedes technicians said that this new coating reduced friction between the piston, piston rings and cylinder wall by up to fifty percent and achieved a mass reduction of several kilograms.

Since the M276 engine had a 60-degree “V” configuration, it did not require a balance shaft. Other measures to reduce weight included the replacement of aluminum and steel materials by plastics for components such as the thermostat, belt pulley, wheel, heater valve and hydraulic lines. The power plant had a third-generation direct injection system with a non-return high-pressure supply with two separate fuel rails. From the rail, the piezo injectors sprayed atomized fuel into the combustion chambers and were capable of delivering up to five injections per cycle. A coupler module inside each fuel injector ensured that the nozzle module and the piezo actuator module had zero clearance in the longitudinal direction.

The fuel feed was sealed on the high-pressure side with an O-ring at the rail. Another O-ring at the fuel injector sealed the leak line. Furthermore, the seal between the fuel injector and the cylinder head was provided by a Teflon ring. The V6 engine was available in two variations: the M276 DEH for the USA and the M276 DES for Europe and the rest of world. The M276 DEH had homogeneous combustion in which an air/fuel mixture with a lambda of 1 was produced throughout the combustion chamber. This system required no additional exhaust after-treatment measures as the standard three-way catalytic converter could adequately convert pollutants.

For the M276 DES, stratified combustion used a combustible mixture that had a lambda approximately equal to 1 only in the vicinity of the spark plug. As such, lambda values in the rest of the combustion chamber could vary, and range from pure intake air to recirculated exhaust gases enriched with intake air to reduce the combustion temperature. While fuel consumption in stratified operation was lower than homogeneous operation, the excess air meant that the formation of NOx was significantly higher than in homogeneous combustion. As a result, a NOx storage catalytic converter was required.

On the skid pad, the car was able to hold on with 0.92 g of grip while threatening to send its wide 285/30R-19 rear tires drifting. There was a brave neutrality baked into the chassis, which was partially born of the tuning but also of the 50/50 weight distribution. Compared with the SL550, the lighter V6 put less mass over the front tires. Although its 1,746 kg (3,843 lbs) curb weight was not exactly light, but it was a hefty 134 kg (295 lbs) lighter than the SL550. The SL400 therefore was the spry one, with a rather playful nature and live-wire steering (2.1 turns lock-to-lock). With exception of the engine, the SL remained unchanged. As with the SL350, the SL400 was in most export markets only available in AMG Sport spec. In Germany, it came with a sticker price of €97,800, in the UK it cost from £72,500 onwards and in the US, it started at $84,000.

For that outlay you got AMG body styling, 19-inch AMG wheels with 255/35 front and 285/30 rear tires, plus lowered sports suspension with stiffened dampers, sports seats with perforated leather, a panoramic glass insert for the vario-roof, and parking sensors. As standard, the SL400 also boasted designo Platinum White Pearl piping on the door armrests, center console, seat side bolsters and headrests. Not forgetting Comand Online with Bluetooth connectivity, Mercedes’ Intelligent Light System with bi-xenon headlamps, metallic paint, and a plethora of airbags and safety systems designed to keep you alive in the event of a crash.

The 2016 facelift

Ever since the 300SL was launched in 1954, the car has been an icon of style. It inspired the elegant 190SL, and later also the "Pagoda" model, which stood out for its lithe, compact shape. 35 years after the Gullwing’s birth, the R129 was an epitome of sleek modernism. With the R231 something went wrong. People called its design "slightly awkward" and remarked that it broke a long line of beautiful SL designs. And it was especially the rear with its oversized taillights that caused criticism.

Of course, people at Mercedes-Benz heard the remarks, and this might be the reason why a midcycle refresh was already introduced at the end of 2015 for the 2017 model year, rather early and as such a first for an SL. This way the Swabians were trying to polish both sides of the coin that made up the SL for men like Ola Källenius. Not anymore head of AMG, but now in his new position as member of the executive board and in charge of sales and marketing, he saw (and still sees) the perennial favorite as a front-runner in a wide variety of disciplines, combining luxury and performance like no other vehicle in the segment: "Only the SL offers driving pleasure in a unique combination: whether pure sporty roadster feeling or relaxed comfortable cruising." This interplay between luxury and performance, sensuality and sporting spirit could be seen in the new design of the front end of the updated SL.

The SL is a long, elegant car with its vented expanse of hood stretching out ahead of the driver

It now gained the latest Mercedes front end with the three-pointed star set in a grille specked with twinkling chrome highlights.

The grille opening flipped 180 degrees to form a conventional trapezoid shape. By having corners that converged upward, the inner edges of the headlights presented natural, parallel edges with the central opening. Those alterations, plus the smooth sheet-metal, finally eliminated the crisscrossing angles and geometric leftovers from the 2008 version of the R230.

The new grille was apparently inspired by the one of the 300SL W194 that won the 1952 Carrera Panamericana. This design would appear also on later Mercedes-AMG models that are unrelated to the SL. Other improvements were the new standard-fit dual LED Intelligent Light System headlights, which were wider than the previous single-lamp units, the stretch routine making for a more balanced face. The edge area and other design components of the headlamp housing were retained in black - conveying an effective sense of depth. The five functions of the LED Intelligent Light System included daytime running lights, cornering light function, camera-based active light function, roundabout light function and also the enhanced fog light function.

This left the below bumper intake area free from lighting. On unlocking the SL, the welcome light greeted the driver with an exceptional lighting display: the LED fiber optics in the headlamps lighted up in blue after opening the vehicle and then transitioned to white locator lighting.

The SL’s width was further accentuated with new lines in the lower bumper, as well as a wide, narrow "A-wing" spread between larger, square-ish intakes. Two power-domes accentuated the long, drawn-out hood. AMG body-styling was now standard equipment. While still not overly elegant when viewed dead-on, the new front was a big improvement. After having worked on the front, the designers seemed to have run out of ideas. The profile view received nothing more than slightly larger non-functional air outlets with wing-like chrome inserts. And the unfortunate rear end with its large one-piece taillights remained almost untouched with the exception that the light-cover was now all red. The bumper got air extractors along the edges and more rakish trapezoidal tailpipe finishers flanked now a diffuser-like insert.

The cosmetic efforts increased the SL's length from 4,613 cm (181.6 in) to 4,630 cm (182.3 in), and dropped its height from 131.57 cm (51.8 in) to 130,05 cm (51.2 in). Moreover, there were a couple of adjustments to the “rather nondescript interior”, as one magazine called it. This included a new steering wheel design with a round center section and an all-black color scheme for the instrument cluster and dash-mounted analog clock. The red ambient lighting inside the cabin now could be changed to either white or blue. Saddle brown leather hides joined the options list and a second USB port was added to the connection options in the center console storage area.

Other improved or new comfort appointments included an extended operation of the electrohydraulic vario-roof. If opening or closing the roof had started at standstill, it could now be continued up to a speed of around 40 km/h. That separator within the trunk -- a plastic cover that was moved to a different position depending on whether the top was up or down -- now was electrically powered. A further practical detail in the trunk was the loading setting -- the roof stowed in the trunk could be swung upwards by approximately 25 degrees at the press of a button to help you get your luggage in or out.

Brilliant blue and designo selenite grey magno were added to the colors chart and the range of light-alloy wheels in 19 inches standard size had also been extended. New additions included a 10-spoke and a 5-spoke wheel, both with a high-sheen finish in high-gloss black. On top of this there were six additional new AMG wheels as part of the accessories range.

Mercedes-Benz had outdone itself by creating some stunning interiors in the last couple of years, the problem is that in comparison the SL’s cockpit now felt even after the update a generation old in terms of design and connectivity. It would be a pleasant enough car in isolation, but for a car pitched as Mercedes’ flagship drop-top, it felt like a great drivetrain in need of a new home. And with the latest product onslaught offering a range of open-top alternatives from SLC to AMG GT to S-Class Convertible, one cannot help but feel whether there were not better options available.

When the revised SL came to market in April 2016, its prices remained close to the current model, which meant about €99,400 in Continental Europe for the base SL. In the UK it started at £73,850 and in the US at $86,000. The SL500/550 cost some €123,900, in the UK it was available from £85,350 and in the US from $109,000. As already before, the updated models were not easy on the wallet, but at least now they were a bit easier on the eyes.

The most obvious change in the interior was the revised steering wheel with a round center section. As the updated SL was just a facelift of the 2012 car, Mercedes-Benz did not fit the mouse-like controller for the Command Online infotainment system found on other more modern models. Instead, for practical and economic reasons it was decided to stick with the old swivel wheel found in cars like the SLC. It was still easy to use and quite responsive though. There was also Apple CarPlay integration and a huge array of other features

Technical aspects

Where AMG caters to the sun-hungry millionaires, the SL500 (SL550 in the US) with its fabulous 455 hp V8 engine and above all the SL400 seem almost bourgeois. Even if the slightly increased new price for the entry-level model was no less proud a price. With the prettifying came additional performance, and continuing education in why the SL-Class model range represented four treads on the stairway to roadster heaven.

The V6 was the only engine that received (so shortly) after its launch an update for the facelift and now achieved 367 hp and 500 Nm (369 lb-ft). The new figures improved the 0-100 sprint from 5.1 seconds to 4.9 seconds, giving always enough punch when overtaking. It showed that the “budget” SL was an incredibly satisfying starting point. The differences to the V8, though, were the lighter curb weight and having to work it marginally harder to draw out the performance. The V6 engine was 55 kg (121 lbs) lighter than the V8, so the SL400 got an entirely different suspension and you could feel those missing kgs in the sprightlier movements of the car's nose. What you got in the SL500, then, was more acceleration and meatier dynamic sensations.

People had liked the deep rumble sound of the SL350. Luckily this had been retained for the SL400 and now the slightly more powerful SL400, which was called SL450 in the US, was in this respect as convincing. It was fitted with a completely different exhaust than the V8, so it was gruffer in every one of the five driving modes before you started pushing hard.

Finally, the non-AMG SL models received the superb 9-G Tronic transmission

But that was not the end of the good news, for the first time in the SL, both non-AMG engines were mated to Mercedes' own 9G-TRONIC PLUS automatic transmission. In case of the SL500/550 the new transmission allowed the V8 with its unchanged engine to reduce its 0-100 km dash by two tenths of a second to 4.3 – matching a Porsche 911 Carrera. Compared with the 7G-Tronic, the technical and economic progress was reflected in 9 forward gears using 10 main assemblies compared with 7 forward gears using 11 main assemblies. On top, the transmission managed with the same installation space as the predecessor model and was also 1 kg lighter at 95 kg, including oil and converter. It could handle torque of up to 700 Nm.

The large gear spread (it was the first version with an overall spread of over 9:1) allowed the speed level of the drive motor to be lowered (down-speeding), which was a big factor in improving energy efficiency and thus reducing fuel consumption. In addition, the lowered speed level improved noise-vibration-harshness comfort. A speed of 120 km/h was achieved in 9th gear at an engine speed of approx. 1,350 rpm, with exterior noise being reduced by up to 4 dB(A).

As with the 7G-Tronic, a torque converter was used as the starting element. Largely taken over from the predecessor, it featured a torque converter lock-up clutch and a twin-turbine torsional damper with centrifugal pendulum technology. The torque converter lock-up clutch could be engaged in all 9 forward gears. Transmission control was as before fully electronic. The shift elements were controlled via a new type of hydraulic direct control with electromagnetically actuated valves, enabling fast and at the same time smooth gear changes.

A nice feature was “DYNAMIC SELECT”. It allowed the vehicle characteristics to be adjusted in seconds at the touch of a button, as the system modified the setup of the engine, transmission, suspension and steering at the driver's behest.

Just how sporty the SL felt on the road depended on your selection from the Dynamic Select menu of Comfort, Sport, Sport+, Individual and Eco modes. In Comfort (C) setting the car was more refined than a roadster had any right to be. Even with the roof down, engine and tire noise were extremely well suppressed. With the optional wind deflector in place, it was perfectly possible to hold a conversation or hear the stereo at motorway speeds.

Select Sport Mode (S) and everything was more immediate. The engine rumble became more present as the revs built, while steering weight increased, the ride firmed and the responses of throttle and gearbox sharpened. Sport+ (S+) was another level with more leeway in the stability control system, as the SL’s rear end powered you out of corners. Even using the paddles, the smooth, quick gearbox never changed type to deliver the punching up-shifts you would get in a more overtly sporting automatic roadster. The active dampers further tightened body control and the turn in was sharp but unsurprisingly. We should not expect the big roadster to change direction with the nimbleness of a Porsche 911. There was always the feeling that you were being spirited through the bends on a wave of electronic trickery rather than good, honest rigidity and grip.

The Eco Mode (E) would start a fuel-efficient setting with a “sailing” function, while the Individual Mode (I) allowed individual adjustment of various parameters to suit the driver’s requirements.

Should the SL owner have chosen the optional AMG suspension, the car would sit some 10mm lower than standard and fitted with harsher springs and torsion-bar stabilizers. That meant the ride would get choppy in Sport+ mode. Overall, the author felt that the non-AMG powered SL was at its best eating up the ground in the Comfort Mode, then flicking to Sport for the twisty bits.

Active Body Control (ABC) had seen a revision too, as it now came with a "Curve Tilting" function, seen first in the S-Class Coupe. Curve tilting replaced the Eco mode in the drive settings. Mercedes-Benz considered this a comfort feature, which is why it had its own setting. It also did not operate in either of the Sport modes. It applied a maximum of 2.65 degrees in the speed range from 15 to 180 km/h and could be set via DYNAMIC SELECT ("Curve" or CV), noticeably reducing the effects of lateral acceleration on the vehicle occupants. It was a little bit like riding on a motor bike around corners.

It would have been better though to have a knob instead of a button to select one of the different drive modes. The operation via a button meant that you needed to cycle through every option to get the one you wanted. This was ok when there were only three choices. Now there were five, which meant you had to pay attention.

A side-by-side comparison between old and new

The AMG models

The revised SL63 and SL65 had their world premiere at the 2015 Los Angeles Auto Show; the market launch would begin in April 2016. At the presentation, Tobias Moers, CEO of AMG, remarked: "Our updated SL63 and SL65 high-performance roadsters offer a unique driving experience, combining hallmark AMG Driving Performance with the pleasures of open-air motoring and superior comfort on long journeys.”

The AMG models included a twin-blade grille as well as larger air intakes and hood vents. The SL63 received 10-spoke 19-inch light alloy wheels finished in titanium grey with a high sheen finish, and the SL65 featured 19-inch multi-spoke ceramic polished forged wheels. The standard AMG sport suspension was based on the Active Body Control System, and an optional Performance Suspension was offered for the SL63.

Hand-stitched Nappa Leather wrapped the seats and leather encased about 85 percent of the interior from the headliner to the lower door trim in the SL65

Interiors continued virtually unchanged with the exception of slightly revised minor switchgear and the already mentioned redesigned steering wheel. Hand-built AMG engines powered virtually unchanged the two AMG versions of the SL. The SL63 got the twin-turbocharged 5.5-liter AMG V8 that produced 577 horsepower and 664 lb-ft of torque at 2250 rpm, combined with the AMG SPEEDSHIFT MCT 7-speed sports transmission to handle the power transfer to the rear wheels. Engine and transmission software were revised to deliver faster shifts than the previous model, especially in Sport Plus mode and manual shifting.

The twin-turbocharged 6.0-liter AMG V12 powered the SL65, producing 621 horsepower and 738 lb-ft of torque, combined with the AMG SPEEDSHIFT PLUS 7G-TRONIC designed to handle the massive torque. The SL65’s self-driving capabilities did not quite rise to the level of those on the latest E-class, although as it is, there was still Parking Pilot and lane-keeping assist and Night View Assist Plus to dazzle your passenger. The Bang & Olufsen audio system employed with Frontbass cavities in the chassis structure to enhance bass response so that your tunes did not sound wimpy with the top lowered.

The SL65 accelerated from zero to 100 km/h in 4.0 seconds, with the SL63 slightly slower at 4.1 seconds (previously 4.2 s). Not that this really mattered. The SL63 was as before magnificently quick on the open road, and listening to its snarling V-8 pulse with the top down was pure joy. This was still a lord of open-air motoring, with a regal price tag to match: $151,250 to start, or more than $40,000 above the gentlemanly SL500/550.

Of course, if true excess was your thing, Mercedes-Benz would still sell you the V12 SL65 for $220,475. That was a lot cheaper than the $263,000 Bentley Continental GT Speed Convertible, which was just as fabulous. Everything from the C-Class up to the S-Class had vastly better technology for daily use. And not having something as basic as touchscreen controls in a car of this caliber felt like penny pinching, even though it probably got more to do with packaging new hardware.

Due to low demand, the SL65 was stopped in July 2018, and the SL63 in May 2019. It should be the last time that a V12 had powered an SL. And in 2018 nobody would believe that in 2022 a four-cylinder engine would be one of the choices to power an AMG SL

The updated AMG cars had swapped their badges, now the AMG logo sat on the left side

Even the door knob came with an AMG logo

“Special Edition” models

Edition 2Look

What had already started with the R129, was continued with the R230 and now with the R231: the presentation of “Special Edition” models. The first ones were the Edition 1 and for the SL65 the 45th Anniversary Edition, both of which have already been discussed earlier in this book.

In spring 2014 the 2LOOK Edition was launched together with the SLK CarbonLOOK Edition. The 2LOOK Edition was supposed to turn heads. So it was offered in a combination of a light-colored paint finish, such as designo magno cashmere white, designo diamond white bright, tenorite grey or iridium silver, with a vario-roof in high-gloss black. For a more discreet appearance, it was also possible to choose a roof in the vehicle's body color. The spectrum of alternative colors for the special model comprised black, obsidian black and magnetite black. Further highlights were the high-sheen 19-inch multi-spoke light-alloy wheels or the optionally available 19-inch AMG 7-twin-spoke light-alloy wheels painted in high-gloss black and featuring a high-sheen finish.

The interplay of light and dark was continued in the interior. The seats featured a sporty looking longitudinal piping design in black nappa leather contrast with inserts in designo nappa leather in platinum white pearl. The side sections of the door armrests and the center armrest also featured contrasting designo platinum white pearl. The two-tone design was also in evidence on the designo steering wheel and the AMG floor mat with AMG lettering and edging in designo platinum white pearl.

There was also designo trim in black piano lacquer to underscore the special model's exclusive look. The expected roadster comfort was ensured by a range of standard-fit features comprising the Active Multicontour Seat package, climatised seats and AIRSCARF neck-level heating for driver and passenger. The 2LOOK Edition was available with both the V6 and V8 engine for an additional charge of €11.305 (SL350) and €9,877 (SL500). This represented a saving of up to €2,345.

Both respective AMG models became available in June 2014, but not only as 2LOOK versions. Instead, in the US they were also offered as “High Contrast Styling” models (Code P42) with similar features. The vario-roof, the cross-strut in the AMG front apron, the exterior mirror housings, the fins on the wings and bonnet, the surrounds of the LED daytime running lamps, the spoiler lip and the insert in the AMG rear apron, all were finished in high-gloss black. The tailpipe trim elements featured a black chrome-plated finish, while high-gloss chrome was reserved for the twin louvre of the radiator grille and the AMG lettering. Further highlights were the red-painted brake callipers and 19-inch (front), 20-inch (rear) AMG 10-spoke forged wheels, painted in matt black and featuring a high-sheen finish.

Both, driver and passenger, sat in AMG sports seats featuring an AMG-specific diamond pattern (which was usually only reserved for the SL65) in Exclusive nappa leather with contrasting trim in designo platinum white pearl nappa leather and with the AMG emblem in the backrest. The door center panels also showcased the AMG diamond pattern. Here too, the designo leather in platinum white pearl adorned the side sections of the armrests, the doors and the center armrest. Black leather gave the designo roof liner character. This exclusive look was underscored by an AMG Performance steering wheel in nappa leather/Alcantara with a bezel in high-gloss black.

The steering wheel featured a high-quality hand-crafted finish with white contrasting topstitching. Its bottom section incorporated an insert in designo platinum white pearl nappa leather, while in the 12 o'clock position there was a black marking. designo trim in black piano lacquer (AMG carbon-fibre trim was alternatively available as a no-cost option), AMG floor mats with AMG lettering and designo platinum white pearl edging and vent surrounds in high-gloss black added the defining finishing touches to the two-tone look.

The additional charges for the AMG Edition models were €9,401 (SL63) and €5,355 (SL65)

2014 World Championship Collector’s Edition

This edition should actually be called super exclusive edition, as it was not only very expensive, but also only available 38 times.

At the end of the 2014 Formula One season, Mercedes-Benz had every reason to be happy, at least on the sporting level. It had dominated the Formula One season from start to finish, winning both constructor and driver Formula One world titles. In fact, Mercedes had managed to win 16 of the 19 Grand Prix races, also thanks to both its drivers Nico Rosberg and Lewis Hamilton, the latter being crowned world champion, with Nico Rosberg his runner-up. Such success deserved a tribute, hence why Mercedes-Benz decided to build a special edition of the SL63. This series of 38 cars was equally divided into two sets of 19 units (referring to 19 Grand Prix), the "Rosberg" version and the "Hamilton" version. Lewis Hamilton suggested the basic color scheme of black. Nico Rosberg chose white as the color theme.

The Hamilton car wore the special designo night black magno paint finish, which was also found on the exterior mirrors, door handles and wheel rims. Lettering, fins and stripes on the rear bumper added contrasting gold accents. The tailpipe trim was black chrome-plated. Black and gold also dominated the interior: Gold-colored stitching adorned the black nappa leather seats, the instrument panel and center console were also clad in designo Exclusive Nappa Leather black, and the trim parts gleamed in gold.

As a contrast, Rosberg's SL presented itself rather differently. Painted in designo cashmere white magno, other parts such as door handles, wheels, lettering, fins, the bar in the front bumper, daytime running light surround, window trim and the tear-off edge in the trunk lid created a well-judged contrast in designo himalaya gray. Both Formula One drivers agreed on the tailpipe trim though: They were also black chrome-plated on the white car.

Designo Exclusive Style titanium gray leather set the tone for the interior of the Rosberg model. The seats, steering wheel, door edges, hood cover and upper part of the instrument panel, for example, were covered in it. The lower part of the instrument panel was finished in nappa deep white, as were the center console and door trim. The trim parts gleamed in designo cashmere white magno.

Both the Rosberg and Hamilton models came fully equipped. These included the AMG Driver's Package, numerous assistance systems, AMG sports suspension, AIRSCARF, Bang & Olufsen Beo Sound AMG sound system, panoramic vario-roof with MAGIC SKY CONTROL, AMG sports seats, and much more.

Mercedes-Benz offered the 19 black and 19 white models exclusively to members of the Mercedes-Benz Circle of Excellence. True to the team spirit, the exclusive vehicle editions were initially only available as a duo, later also as a single vehicle. Buyers had also received a Lewis Hamilton or Nico Rosberg helmet. Other attractive extras included a limited-edition IWC Ingenieur Chronograph in the Nico Rosberg or Lewis Hamilton edition, an F1 book signed by the drivers, and an invitation to the opening race of 2015 in Melbourne. The cars should have been handed over during the 2015 German Grand Prix, which was supposed to take place between July 17th and July 19th of that year. As neither the Hockenheim nor the Nürburgring management were able to meet deadlines, the German Grand Prix was eventually cancelled and the cars were handed over one week later at the Hungarian Grand Prix, which was incidentally won not by one of the two Mercedes drivers, but by Sebastian Vettel on a Ferrari.

The price for the unique duo was €629,510, a single vehicle cost €320,110 (incl. 19 percent VAT). The black car that can be seen on these pages sold on July 07th 2018 with a mileage of just 30 km for €256,280 by Artcurial.

As already mention before, there were only 19 of each of the white and black models - analogous to the 19 Formula One circuits of the 2014 season. The image of the respective race track was embroidered into the floor mats of the vehicle, adorned a plaque on the center console and also identified the corresponding key.

Mille Miglia 417 Edition

In 1955, private US driver John Fitch and co-driver Kurt Gessl from Germany set off for the Mille Miglia in a works 300SL with start number 417 (it stood for the time of their race start: 4:17 am). After 11 hours, 29 minutes and 21 seconds, they crossed the finish line in fifth place overall and were winner of the production sports car class after 1,597 kilometers on public roads from Brescia to Rome and back.

In 2015 Mercedes-Benz decided to celebrate the 60th anniversary of this motor racing success with a special model of the SL Roadster. The SL Special Edition "Mille Miglia 417" provided a special experience of the unique symbiosis of maximum comfort and motor racing spirit that traditionally characterized every SL.

The Special Edition added a distinctive note, among other things, with red exterior highlights and fine materials in the exclusively appointed interior. Red was the color of the lip on the front spoiler, and a red trim strip on the rear spoiler contrasted with the matte carbon. Red brake calipers gleamed through the spokes of the black AMG Performance wheels, which sported subtle red surrounds and had diameters of 19-inch at the front and 20-inch at the rear.

The Special Edition "Mille Miglia 417" came as standard with a magnetite black metallic paint finish. Optionally the two designo night black magno and designo cashmere white magno matte paint finishes or the designo diamond white bright shiny paintwork were also available. A small "SL Mille Miglia 417" lettering on the fenders also indicated the special model. The AMG Line seats as well as the black center console with contrasting inlays and red edging were some of the new features. The leather headrests sported an embossed carbon structure and an embroidered "SL Mille Miglia" label. Red edging also outlined the black door center panels with red armrests.

The steering wheel was wrapped in red and black nappa leather with sporty embossed carbon structure and bolstered the sporty ambience. The trim elements had a matte carbon finish. The black floor mats with red edging came with an embroidered "1000 Miglia" label.

Technically, this edition did not deviate from the standard cars. Customers could choose between the SL400 with its 6-cylinder engine and 333 hp and the SL500 with a V8 and 455 hp output - the latter already anticipated a performance upgrade of the 4.7-liter biturbo engine, which would also be available to other 500 models later in the year. Standard was the cornering dynamics assistant and adaptive adjustable damping. Active Body Control (ABC) was also on board.

The price premium for this edition was €14,800 for the SL400, and €12,800 for the SL 500. The cars could be ordered from April, 2015 onwards and were limited to 500 units.

Designo Edition

A few weeks before the start of spring in Europe in 2017, Mercedes-Benz was sending its two roadsters, the SL and SLC, into the automotive spring with attractive editions. The SLC was available as a “RedArt Edition” and the SL as a “designo Edition”. While the compact SLC special model emphasized sporty dynamics, the SL focused on exclusivity and refined interior design.

With the new designo Edition, which was introduced at the Geneva Motor Show in March 2017, the SL should further increase its exclusive character. The model came with stylish design elements and high-quality materials in the exterior and interior. On the exterior, the metallic paint in brilliant blue, the 19-inch (front) or 20-inch (rear) AMG forged wheels in 10-spoke design and flics of chrome in the front apron created a special look. A subtle hint of the roadster's special status was provided by the badges with designo Edition logo mounted on the side between the small chrome wings.

Both, driver and passenger experienced the special character of this SL edition with exclusive design elements in the interior. Seats and door center panels in designo leather nappa porcelain/black with exclusive designo graphics, the interior headliner in designo DINAMICA porcelain and designo seat belts in white created a nicely refined ambience. This was complemented by other equipment features such as ambient lighting, the two-tone multifunction sports steering wheel in a three-spoke design in black/porcelain nappa leather, the DIRECT SELECT selector lever in porcelain leather, the designo trim element in champagne white piano lacquer, and the floor mats with designo badge and piping in porcelain.

To enhance the comfort level, the standard equipment also included seat climate control, AIRSCARF headroom heating, the Active Multicontour Seat package, which included massage, driving dynamics and PRE-SAFE positioning functions. Additional standard features were the Driving Assistance package Plus with DISTRONIC distance pilot with steering pilot, Active Brake Assist with crossing function, Active Blind Spot Assist, Active Lane Keeping Assist and PRE-SAFE PLUS.

This edition was available for two years until March 2019 and available for the SL400 at a surcharge of €16,481 and for the SL500 for an additional €13,030.

Grand Edition

Grand Edition – that is what Mercedes-Benz calls particularly exclusive special models. With the SL Grand Edition, the company was sending its R231-series roadster in early 2019 into its final product cycle. The new Grand Edition models of the SL400 and SL500 came with numerous highlights and special color combinations for the exterior and interior. This edition could not be ordered with ABC.

When it came to the paint finish of their Grand Edition model, customers could choose between four metallic tones and plain black, from a radiant white (designo diamond white bright) to various shades of gray and obsidian black. Applications in high-gloss chrome and matte silver gave the front bumper a special look.

As all previous edition versions, the Grand Edition models rolled on 19-inch AMG forged wheels in a 10-spoke design at the front and 20-inch at the rear. These were painted in high-gloss black and feature a high-sheen turned rim flange and spokes of the same design. The badges with the SL Grand Edition logo on the side of the fenders provided again a subtle hint of the special model. The eye-catcher in the interior was the designo tundra brown pearl leather with its shimmering metallic surface. It could be found, among other things, on the standard multifunction sports steering wheel. There, the upper and lower segments of the steering wheel rim were finished in smooth tundra brown pearl leather. The grip area felt particularly good in the hand with perforated black nappa leather.

The SL's traditionally extensive standard equipment was topped in the Grand Edition models, as they featured among other things the AIRSCARF head space heating system, the sports suspension with 10 mm lowering and firmer tuning, active multi-contour seats with massage function and driving dynamics function, seat climate control, Driving Assistance package Plus and Active Parking Assist.

Prices for the SL400 started at €114,811, while the SL500 Grand Edition cost at least €135,993

The Tuning scene

Brabus

When one independent Mercedes tuner deserves the first spot, it is of course Brabus that springs to mind. Like most of the other tuners, Brabus used more and more the SL AMG versions as basis for their modifications, although they continued to offer performance packages also for the standard six- and eight-cylinder versions.

One might think that AMG had already a pretty solid feeling for what customers wanted and that there was little room for further modifications. But as so often in life, if one just tries hard enough, the ante can always be upped and more power squeezed out of a given engine that had already been extensively modified. This way also Brabus’ chief tech-honcho and former Daimler-Benz engineer Ulrich Gauffrés thought that he could do better. Former Brabus owner Bodo Buschmann (he passed away in 2018) called him respectfully “the professor”.

For him this extensively modified engine suddenly became the standard engine from where to start. That meant for Brabus and most tuners to revise the supercharger with a custom vibration damper and replace the drive pulley for a better belt-drive geometry. The already big exhaust would be changed into something even bigger and the intake and induction systems needed to be modified.

Then the engine management unit had to be altered or replaced, so that the big V8 could be talked into making use of the upgraded breathing apparatus. In addition, the gearbox needed to be addressed so that it could handle the additional torque. High performance metal catalysts and an auxiliary circulation pump with opposing radiator helped to boost power output and naturally the first thing that prospective customers wanted to have removed was the electronic speed limiter.

For the R231 Brabus offered an attractive designer suit as well as exciting alloy wheels up to 20 inches in diameter, even more agile handling thanks to professional suspension tuning, a power increase to 520 hp, which made the SL500, now Brabus B50, up to 300 km/h fast, and options for the interior tailored to the wishes of the SL owner.

Brabus in the 1970s

A 2012 Brabus B50

Sporty, elegant body-styling components that had been trimmed in the wind tunnel for maximum aerodynamic efficiency are the specialty of the Brabus designers. Whether with or without the AMG sports package, a tailor-made front spoiler and attachments for the side skirts and rear apron have been developed for both body variants of the SL. In addition, there was a Brabus rear spoiler and side air outlets for the front fenders.

To achieve a perfect fit, all parts were produced in original equipment quality. Equally important to the individual look were the Brabus monoblock wheels in original equipment quality, which could be ridden on the new roadster in four different designs in 18-, 19- and 20-inch diameters. As a maximum combination, Brabus Monoblock F, Q or R wheels in the dimensions 9Jx20 at the front with 255/30 ZR 20 tires and 9.5Jx20 with 295/25 ZR 20 tires at the rear could be driven on the R231 series. To further enhance the driving dynamics of the new roadster, Brabus developed customized suspension solutions in cooperation with technology partner Bilstein. Brabus sports springs were available for the SL350 with conventional steel suspension. For all SL models with ABC suspension, Brabus suspension engineers developed an electronic module that lowered the body by approximately 25 millimeters.

This made the SL500 ideally equipped for even more performance. The Brabus B50 - 520 PowerXtra CGI performance kit coaxed an extra 85 horsepower from the 4.7-liter eight-cylinder biturbo engine. For this purpose, not only was the Brabus PowerXtra module integrated into the engine electronics in plug-and-play technology to achieve more power with special maps for injection and ignition as well as a moderately increased boost pressure. The conversion also included an additional water-cooled charge air cooler supplied by an auxiliary electric pump.

Lowering the charge air temperature benefited not only the power output but also the stability even under extreme operating conditions such as in the desert. Instead of the standard 435 hp, 520 hp and a maximum torque of 820 Nm were available after the conversion. This allowed the two-seater to accelerate to 100 km/h in just 4.4 seconds. With the Brabus Vmax Unit included in the engine tuning, the top speed could be electronically limited to 250, 275 or 300 km/h as desired.

A Brabus stainless steel sports exhaust system with four chrome-plated tailpipes was not only indispensable for an SL with a Brabus high-performance engine. It was also recommended for all roadster owners who want a sportier engine sound and an even more striking rear view of their two-seater. For the SL500, Brabus offered a variant with flap control. Here, the engine sound can be regulated between discreet and sporty excitement at the touch of a button on the steering wheel. A further plus in driving dynamics can be achieved with the Brabus differential with 40 percent locking effect.

The two-seater cockpit could be trimmed even more for luxury and individuality at Brabus. The range of options extended from door sill trims with illuminated Brabus logo and a speedometer up to 320 or 360 km/h to carbon and fine wood trim in every conceivable shade and various finishes. The in-house upholstery shop created exquisite Brabus interiors from particularly soft yet hard-wearing Brabus Mastik leather and Alcantara.

You would normally assume that a 630 hp SL65 was not really underpowered - or was it? Brabus thought otherwise, they presented in 2013 a version with 800 hp and called it simply “B12”. This is no typo: Brabus limited the top speed of the Brabus 800 Roadster to 350 km/h (217.5 mph). Dizzying, like the other values of the pimped SL65. The six-liter twelve-cylinder biturbo produced said 800 hp after the Brabus treatment, and accelerated from zero to 100 km/h in 3.7 seconds (standard: 4.0 seconds). It reached 200 km/h in 9.8 seconds, maximum torque was 1,420 Nm, but in order not to damage the transmission, it was electronically limited to “only” 1,100 Nm.

As long as money was no object, the customer could ask for any interior cover material

This performance was made possible by a special twin-turbo system with two special manifolds each with integrated turbine housings and high-performance chargers. Four water-cooled intercoolers required space, hence the eye-catching air scoop on the hood. The monster rode on 20-inch wheels, and the bodywork was adorned with numerous carbon add-on parts. This aerodynamic kit was not just for looks, however, but was necessary to ensure that the vehicle remained controllable despite its extreme performance. In addition, the body was lowered by approximately 2.5 cm by a control module developed by Brabus.

Brabus garnished the unique high-performance experience with an acoustic treat: the stainless steel sports exhaust system, which was offered for the SL, also optimized performance by reducing exhaust backpressure. On top it came with a variable sound thanks to its integrated exhaust flaps: the V12 could be driven either emphatically discreetly in quiet "Coming home" mode or in the "Sport" position, which elicited an extra powerful V12 sound from the engine. With its titanium/carbon tailpipes measuring 90 millimeters in diameter, the Brabus exclusive exhaust system was also an absolute visual treat.

Brabus showed the, quote: "world's most powerful roadster" at the 2013 Geneva Motor Show. Prices started at €349,755. In 2014 they even introduced an upgraded 6.0 liter SL63 with 850 hp with 1,069 Nm of max torque at a base price of €243,772.

The exhaust note was remarkable to say the least

Also the trunk received special attention

RENNtech

A well-established tuner in the US, who does not only concentrate on Mercedes, is RENNtech. The company was formed in 1989 by Hartmut Feyhl, who had formerly worked with AMG as technical director for their US operation. He was during his AMG days largely responsible for the famous AMG Hammer, a super car that was based on the W124 E-class.

Anyone who owns an SL63 AMG should have no doubts about the “daylight capability” of his/her SL. There is no question that the 537-hp roadster is a sight to behold and a sound to hear. However, the attention-grabbing value of the SL can still be increased. What it takes to make the AMG model athlete look even more aesthetic doesn't have to be all that much. A nice, big wheel - as demonstrated by US tuner RENNtech – does not miss its mark here.

“Deep Monolite" was the name of the rim in double-spoke and discreet bicolor look, which made the SL63 look special. The wheels were available in 20 and 21-inch sizes, and came in different designs and finishes to match all body styles of the SL-Class models.

But of course, RENNtech did not just offer wheels or body kits. Their main business was/is still the engine tuning. The “R1 Performance Package” was the perfect entry level performance upgrade for the SL63. Combined with an ECU upgrade and the latest, 3rd generation diverter valve, it was possible to add up to 91 hp and 179 Nm (132 lb-ft). The addition of the upgraded diverter valve helped to handle boost spikes in high boost pressure applications better. A surplus of boost would be released to the atmosphere and the turbocharger could be supplied with air quicker after the shifting process. This helped to eliminate the turbo lag.

This particular SL63 is fitted with Deep Monolite 10.2 in custom two-tone finish, and features a lowered suspension, which makes the wheel really stand out. Also the AMG aero kit on this car is finished in the same color as the body, and not the usual exposed carbon. That helps to make the car less ostentatious. But one has to wonder, how comfortable the ride in this car will be

A comparison between the stock SL63 engine and one with the R1 upgrade

If you really wanted to push it, the R3+ Performance Package was the right option. R3+ was the final evolution stage of the R-Perfor-mance line for the M157 series and was intended as a track upgrade. To reach the highest output level and guarantee longevity, especially in high performance applications such as continuous track days and road course testing, 100+ octane gasoline was mandatory.

Included in the R3+ Package were upgrades to the ECU, diverter valve and air filters. It included a carbon fiber air box kit, stainless steel sport mufflers and upgraded turbocharger, as well as upgraded stainless steel downpipes, which were handcrafted, and an intercooler upgrade kit. This kit allowed to flow more than twice as much coolant as the OEM pump. This increase in flow removed heat from the incoming air; allowing for a denser air/fuel mixture and substantially cooler charge air temperatures over the entire operating range. The addition of the upgraded diverter valve helped the engine to handle boost spikes in high boost pressure applications better. The 4-piece air box kit was made out of the highest quality pre-peg carbon fiber. The kit came complete with flow optimized turbo tubes to increase the volume of incoming airflow

A comparison between the stock SL63 engine and one with the R3+ upgrade

With the upgraded turbochargers, the R3+ package was able to increase performance by up to 235 hp to 840 hp at 5,500 rpm and by 374.2 Nm (276 lb-ft) to 1,280 Nm (945 lb-ft) at 3,700 rpm. With increased engine performance it became necessary to further improve the drive line components, most importantly the transmission, in order to ensure maximum power was transmitted to the drive wheels without transmission slippage. This could not be realized anymore with software alone. It was necessary to give the transmission an internal mechanical upgrade to its hardware.

The upgrade consisted first of a complete transmission disassembly and inspection as well as a mechanical upgrade to the transmission clutch packs. This enabled engineers to maximize the amount of friction materials contained within the transmission and in turn, the amount of power which could be transmitted through each forward gear. During final assembly the transmission also received all new gaskets, seals, o-rings as well as a new transmission pan filter. The upgrade led to improved shift response, shift timing, increased torque handling capabilities and greater drivability under extreme conditions without sacrificing around town comfort.

But RENNtech did not only work on the AMG models, upgrades were already available for the SL400 for example. For the V6 model an ECU tuning would boost power output from 329 hp to an impressive 392 hp and would lift torque from 480 Nm (354 lb-ft) to 585.7 Nm (432 lb-ft) at the crank.

RENNtech’s HHT (hand held tuner) offered the driver the ability to switch between tuned and stock

ECU programming. This required no ECU removal

FAB Design

FAB-Design is a Swiss tuner that does not only concentrate on engine tuning and/or body kits. Like Carlsson did with the old SL R230, it created an almost different car around the R231 In case of a “Bayard” called SL63 model they started with a sporty front apron including large cooling air openings. In addition, the extra-light carbon-fiber-reinforced nose provided an extra supply of fresh air for the turbocharged engine.

The redesigned fenders, supplemented by redesigned side skirts, gave the roadster a powerful look, which was complemented by a considerable 70 mm (front) and 120 mm (rear) widening of the standard body. The carbon rear skirt with integrated diffuser stabilized the vehicle even at its top speed. In addition, it generated better downforce at the rear axle in conjunction with the rear spoiler for a special driving experience - even in curves. These improvements allowed the driver to fully exploit and enjoy the increase in power to 630 hp at 5,800 rpm, which was the result of a combination of a sports rear silencer, sports catalytic converters and an optimized engine map.

Also, the torque saw a boost to 885 Nm (652.7 ft-lb) at 2,000-4,500 rpm. The Bayard accelerated from zero to 100 km/h in 3.9 seconds. The name Bayard by the way was derived from a legendary giant horse that was known for its speed and supernatural powers.

Others

Just to name a few other tuners in no particular order:

Graf Weckerle tuning company

A more outrageous design came from the Japanese tuner Vitt Squalo. Did anyone say Koenig Special?

Lorinser was one of the more established tuners

Driving the SL63 AMG

A twin-turbocharged V8 engine with up to 564 hp rumbles under the hood of this 2013 SL63 AMG. How much does the powerful engine change the character of the otherwise relaxed looking two-seater? Anyone standing in front of an SL63 does not want to dwell for long on the theory of aluminum components manufactured using the permanent mold casting process, plastic outer shells for the trunk, revised elasto-kinematics or marketing nonsense like the twin-blade radiator grille. Turn the ignition key, now, immediately.

After a short but powerful burp, the SL's quadruple rear silencer emits a staccato V8 that far too quickly relegates the sports derivatives with the star in the radiator grille to the proletarian corner of East Berlin in the current zeitgeist. Yet this pleasant sound, which even the eight-cylinder masters on the other side of the Atlantic could hardly have composed more perfectly in their prime, is absolutely genuine and unadulterated - at least that's what Friedrich Eichler, Head of Powertrain Development at AMG, asserts. "We achieve the sound image solely through the design of the exhaust system without active aids." Fantastic.

Shortly after the R231 series was launched, AMG was allowed to follow suit - and the even more powerful SL65 was already chattering away with its rear wheels. Some governments might appear to run out of steam financially, but not a good number of private customers. After all, they are paying Mercedes-Benz for the SL63 €159,475 - without optional extras.

As expected, the surcharge list for the SL includes the so-called Performance Package for a slim €14,280, which boosts the output of the 5.5-liter engine by 27 to 564 hp. And since there can never be enough torque, it also increases by 100 to 900 Newton meters. Not that this 100Nm more is really needed, though, because turbo torque is constantly available and the full cache of thrust can be accessed at an unbelievably low 2,250 rpm.

The package also includes a visually questionable carbon trunk lid, a rear-axle limited-slip differential, and an increase in the top speed limit from 250 to 300 kilometers per hour. The latter plays a similarly important role on the first drive on southern Bavarian country roads as pork sausages in the diet plan for vegetarians. The additional torque can hardly be felt either, because either way the car, which still weighs around 1.9 tons despite a strict diet, jumps directly into the back of its two occupants. With legs stretched. Deeply rumbling like a thunderstorm that swells at lightning speed, the latest AMG rages along the road, leveling out almost any gradient and snatching at curves with astonishing gusto.

With 40 percent stiffer bearings and increased negative camber in the chassis as well as more directly designed electromechanical steering, the SL offers a significantly higher lateral dynamic potential than the base model. That base model can keep its socks on, even in bed, but the SL63 runs around bare feet. The roadster takes off one more time with this gentle rumble, as if a small thundercloud is always following it. But even in comfort mode, it rolls off a bit harshly, the 537 hp engine is eager to feel the accelerator’s push, the massive torque is lurking, waiting for the right moment to attack.

It comes quickly, perhaps too quickly for the inexperienced, because, as we know, at 2,250 rpm the alarm is sounded, full alert. It is a good thing that the control electronics are quick and rigorous. If you dare, you can select the sport handling mode, and if you like to go for a ride through the Alps on a wingsuit before breakfast in the morning, you can switch off the ESP completely. Then only the mechanical limited-slip differential helps to handle the force of the eight-cylinder engine.

The multi-clutch transmission works really well, when you let the computer do all the work selecting shift points, but the manual shift function is a bit of a letdown with slow response to shift commands via the steering wheel-mounted paddle shifters. Acceleration rates normally flatten as aerodynamic drag rises. The SL63 seems to do just the opposite as it picks up speed like a rocket leaving the earth's pull of gravity. And here we go again: full throttle applications release a throaty growl from the quad exhaust, accompanied by spine-chilling burbles as the transmission catches each gear. Downshifts are equally as pleasing as the V8 cackles and pops as each gear falls. Evocative. Exciting. Addictive.

Now a racetrack would come handy, but that is not in sight at the moment. In any case, very few AMG-SL owners are likely to meet at track days, although they probably would not be that bad at pushing their cars around a race course. As already mentioned, the two-seater seems a bit on the stiff side over rougher surfaces, but despite its substantial physical size, the roadster is surprisingly agile, offers good feedback, and the holding forces are right. Yes, the steering is perhaps even more sensitive elsewhere in other cars, but elsewhere is not this kind of displacement. And that you can feel always in the AMG, really always.

In other words, agility is subordinate to power, not the other way around. So be careful with your right foot, always keep the car under traction, but accelerate only slightly and progressively. And, again, do not forget to enjoy the sound that is provoked during every—double declutching-- gear change during all the slamming into and out of corners. Driving the SL63 you know that life in the fast lane can be really cool, extra confidence is baked into the chassis by the SL’s suite of electronic gizmos, including the standard stability control with brake-based torque vectoring and the equally standard fantastic Automatic Body Control electronic dampers. Guided by inputs from 13 sensors, the latter is said to reduce body roll versus a car without ABC by 68 percent in comfort mode and 95 percent in sport mode.

Compared with the 429 hp SL550, the 1kg heavier SL63 is a half-second quicker to 100 km/h from a standstill (3.6 seconds) and stops 91 cm shorter from the same speed. With the 285/30R-20 rear Continentals warmed to their optimum operating levels, a quarter-mile is achieved in 11.8 seconds at 198 km/h (123 mph), some 0.7 second and 14.5 km/h (9 mph) faster than the SL550. Grip levels improved as well. Average lateral acceleration is now 0.97 g versus the base car’s 0.94 g best. By the way, these SL63 figures are even better than those of the twin-turbo V12 SL65 AMG Black Series from 2010.

Braking before a sharp turn works quite well, but please be ready before turning, otherwise understeer can follow. Then downshifting, turning, hitting the pedal again, and accelerate perhaps with a bit power oversteer, so that you still stay in your lane. Ok, a Porsche 911 can do all this better, but who cares, when you are surrounded by this andante furioso of a sound. Talking about brakes, the optional carbon ceramic brakes will set you back almost €16,000. It would be interesting to know, how many AMG owners have actually ticked this expensive option on the long list of extras.

With the top down, it is all the more fun, and the wind deflector and side windows can stay down for the sake of aesthetics. Well, and a bit of masculinity, too. The high beltline and the steeply raked windshield ensure an almost storm-free zone behind the steering wheel anyway. Quite a few country roads tempt you on the nav map. And the best thing, they do not cost anything extra.

Alternatives to the R231

The R231 was in a class of its own, in this respect nothing had really changed from previous versions. As the Lexus SC430 did not exist anymore, the SL was the only car in its class with a vario panoramic roof. Other cars that could come to mind as possible alternatives are the Porsche 911, the Jaguar XK, the Maserati Gran Tourismo Cabrio, the Cadillac XLR or the BMW 650i.

All cars except the Porsche and Maserati had the benefit that they were cheaper, some like the Cadillac much cheaper. The Porsche was a different car altogether, its driver would never be happy with the SL, the Jaguar was a beautifully designed, well-built and fast car, especially as XKR with compressor engine, but slightly aged already. The Maserati did not offer the same dynamic and agility and played at $137,000 in a different price league. And the Cadillac was quality-wise not yet at par with the Mercedes. That left the BMW as a highly subjective possible alternative by this author. The German car magazine Auto Bild had a similar idea by the way and had compared both cars in its March 2012 edition.

Although the V8 BMW was some €20,000 cheaper and quality- and feature-wise equally refined, the SL500 impressed the journalists at the end more and managed to win this little contest. The BMW was 28 cm (11 in) longer than the SL and offered rear seats, although not really suitable for adults on longer distances. However, they could also serve as additional space for luggage. Although the BMW had a soft top and no hardtop, its luggage compartment was slightly smaller than the one of the SL, when the SL’s vario roof was up.

Its 4.4 L (268.5 cu in) engine offered 407 hp and 600 Nm (443 lbs-ft) of maximum torque. As the BMW was some 230 kg (507 lbs) heavier, it was less agile than the SL counterpart and consumed more fuel. However, its acceleration of 5.0 seconds was almost at par with the 4.7 seconds from zero to 100 km/h of the SL. His eight-speed automatic transmission was regarded as superior to the 7G-Tronic of the SL, as it reacted swifter to kick down maneuvers. And although the 650i was longer and heavier, its cornering ability was seen as slightly superior. The passengers sat higher in the BMW and had more the feeling of driving in a convertible, when the top was down. The interior was regarded even better than the one of the SL, as it looked more modern and fresher.

The center console containing the iDrive system’s Control Display, the central air vents plus the controls for the audio system and air conditioning was all angled towards the driver, like it was the case with the old 2002 and the centrally located information screen was far larger than the one in the SL.

Also, the instruments appeared to be better visible in the BMW. Quality-wise there was no difference between the interior of both cars. They both earned top marks. So, what made the SL the better car at the end? It was simply the best overall open tourer on the market, not so much for racing but for relaxed, yet fast motoring. The Airscarf and electric draught stop, which the BMW lacked, were two features, which made top-down driving under most weather conditions much more enjoyable.

The 4.7 L engine was an absolute marvel, it made the driver grin whenever he/she hit the pedal. It was also the sound and never-ending push that made the car so desirable (and the testers had not yet experienced the AMG versions). The engine offered more grunt and was more thrilling to drive than the BMW, who always seemed to have to work harder under similar conditions. The SL was a car that was under all driving conditions so much fun, it relaxed the driver, as he loved driving it so much. The SL consumed less fuel (1 l per 100 km) and although its electronic stability program offered slightly fewer options than the one of the BMW, the SL’s optional ABC-suspension made the car corner without any body roll: Yet it was a little slower through corners than the BMW.

And if the driver resisted buying the optional AMG sports package, all the cornering and hard driving could be done with a surprisingly high degree of comfort even over the worst of surfaces with no rattle or squeaks. The car seemed to be built again in the best of Mercedes SL tradition.

Conclusion: it was most of all the new direct-injection V8 engine that made the SL the winner, even at its higher price. The SL350, priced at the level of the BMW, would lose this match. It was interesting that the journalists did not like the designs of both cars. They did not like the elongated massive front of the SL, its fussy rear with the huge taillights and the somewhat bland body design of the BMW. Also, the headlights on both cars did not seem to go down well with them either.

Just in case one was tempted to compare the SL not only with the BMW, but also with the new Porsche 911 Carrera and the Jaguar XKR, the Porsche would beat every one of them with its superior road holding abilities. And when it came to interior beauty and refinements, the Jaguar was in a league of its own. A beige interior with Jaguar’s rich burl walnut veneer and a leather fragrance that cannot be matched by its German competitors, made the XKR in its typical British way as special or unique as its German rivals. At €95,800, the BMW was the most affordable of the four, followed by the Jaguar with €114,400, the Porsche with €114,930 ($151,700) and the Mercedes with €117,100. From a practical point of view, the BMW was not only the cheapest, but also the car that offered the most space. But if you spent around €100,000 on an open sports car, money and space were not the only deciding factors.

Factor in emotion, and the Jaguar was appreciated for its wonderfully throaty, but thirsty compressor-engine and its unrivalled interior, the Porsche for doing what it can do best: being a true Porsche. And our SL was, at least from this author’s point of view, a perfect mixture of it all. Not the prettiest car, but it offered one of the best engines, coupled with a convincing fuel economy, great handling characteristics and a comfortable, large enough, quality interior. On top, it had something that no competitor could offer: the vario roof. Its successor, the SL R232 won’t, what a pity!

Technical chapters

Active body control—yes or no

To make it short: for the R231 it is at least from the author’s point of view a wholeheartedly YES!

ABC was first introduced in 1999 in the then S-class coupe C215 and is the Daimler-Benz brand name to describe its fully active suspension. It allows control of the SL body motions and virtually eliminates body roll through an interplay of hydraulic, mechanical and electronic parts by some 68 percent, when compared with a car with conventional suspension.

With a push of a button on the center console, passengers could choose between a sporty or comfortable set-up. With the "sport mode" activated, the body roll was reduced by an even more impressive 95 percent. Once the driver of an SL had the pleasure of experiencing the virtues of this system, he/she did not want to drive such a car anymore without it, as it really made (and still makes) this big car corner “like it is on rails”. How does it function? The lower elements of the front axle, the steering gear of the rack-and-pinion steering and the engine mounts are all connected with an aluminum frame-type integral support.

Four suspension struts, which consist each of an in parallel connected steel coil spring and shock absorber, plus a hydraulically controlled adjusting cylinder, are located between the wheels and the SL body. They have the purpose to adjust the cylinder and change the suspension length in order to keep the car level under all conditions. This is nothing really new though. Then a total of thirteen sensors monitor body movements and vehicle level. Four of them are level sensors at each wheel, three accelerometer sensors check the vertical body acceleration, one acceleration sensor measures the longitudinal and another one the transverse body acceleration. Each of the four hydraulic cylinders has a pressure sensor to check the hydraulic pressure, which is supplied by a high-pressure radial piston hydraulic pump, located close to the SL’s engine.

These thirteen sensors supply the onboard control unit every ten milliseconds with new data. The computer compares the acceleration data with the pressure and level data and translates them into control signals. These signals are implemented as precisely metered oil flows by hydraulic servo valves, mounted in series on top of the suspension strut beside each wheel. They adjust the suspension to generate counter-forces to body lean, dive or squat during all possible driving maneuvers, resulting in an unparalleled driving experience.

The height adjustable function automatically lowers the SL’s suspension by around eleven millimeters at speeds between 60 km/h (37 mph) and 160 km/h (99 mph) for better aerodynamics and in order to improve fuel consumption and handling. It also raises or lowers the SL in response to its respective load. In case you have now the impression that all of this sounds terribly complicated and expensive to fix, you are correct on both accounts. We will discuss this issue a bit more in detail in the “Buyer’s Guide” chapter. If the system is regularly maintained, it will not cause any major concerns.

And as the author mentioned already earlier, once the potential R231 owner has experienced its virtues, he/she does not want to be without it. If your car has ABC installed, please DO NOT skimp on regular maintenance. Otherwise, it will cost you (or the unlucky person, who bought it from you) dearly!

In the author’s books that cover the R129 and R230, ABC was lauded for its benefits, but it was also noted that, as already mentioned, careful, regular maintenance was an absolute prerequisite for the system not to turn into a money pit.

With the R231, this had not changed, but it seems that ABC in the more modern SL appears to be more reliable. Another reason can of course be that the R231 is still a relatively new car and ABC problems have not popped up in larger numbers.

It was a pity though for US customers that most US dealers did not order their non-AMG models with this feature.

The R231’s VIN explained

The VIN (as part of the certification tag) is your R231’s unique DNA. All vehicles produced after January 1st 1989 have to have a “Vehicle Identification Number” that is always 17 characters long and starts in the case of Daimler-Benz with “WDD”. There are differences between the North American VIN’s and the one for the rest of the world, sometimes called FIN for “Fahrzeug-Identifikations-Nummer”. For simplicity reasons, we will stick here to the word VIN.

There are a few places where you can find the VIN on your car. The first place is on the vehicle registration and title. Then on any maintenance records from the dealership, under the windshield on the driver’s side, on the steering column and under the hood on the engine block. Another place for the VIN is below the rear right bumper side. The SL’s certification tag can be found on US-bound cars on the driver’s side doorjamb below the lock. It covers next to the VIN also information on the car’s color and weight. The paint code is a three number code to the right side of the VIN. Early cars had it higher up before the manufacturing date on the right side (see also our sample on the following page).

The doorjamb is also the place for the airbag replacement date. For other markets such as Europe, the certification tag is located on the passenger side doorjamb. The engine number is stamped on the engine block behind the left cylinder head (driver’s side).

The US version with certification tag at the B-pillar stump

The picture below shows a certification tag for a US model, a European version will be explained afterwards:

A sample certification tag of a 2012 SL550 (all VIN/data card entries mentioned in this book are NOT from actual cars and for demonstration purpose only)

The top right side of the red tag starts with the paint code, which is in our case 590: Fire-Opal Mars Red. Earlier Mercedes cars up to the 1970s had two paint suppliers, Glasurit and Herberts. In order to identify the respective supplier, either a “G” or “H” was placed in front of the paint code. These characters are not used nowadays anymore. Until recently other letters were used, such as a “C” in front of the paint code, which stood for a clear coat that was applied on top of all paints. Earlier, an “M” for metallic paint without clear coat or a “W” for water-based colors were used.

At the end of 2003, Daimler-Benz started to use a new scratch-resistant clear coat lacquer made up of nano-sized ceramic particles, which were baked and hardened in the paint shop oven. It was a very hard paint finish, applied to all paints, not just metallic, that could better withstand mechanical car washes. In later years, the “C” was dropped. The manufacturing date to the very right should be self-explanatory.

Position 1-3 of the VIN identifies the manufacturer. In our case, it reads WDD, which stands for Daimler AG. The first character is used for the country of manufacture. “W” stands for Germany, “S” for the UK or “1” and “4” for the US.

Position 4 identifies the respective Mercedes model and reads ”J” for the SL R231. An SLK R172 for example would see here “K” instead.

Position 5 identifies the body style. It reads “K” for the SL as Cabriolet/ Roadster. These assignments changed over the years, because earlier R230 cars for example can have an "A” here instead.

Positions 6-7 identify the model within the series.

Position 8 indicates the safety restraint system the car was equipped.

Position 9 (in our case a 2) determines through a somewhat complicated mathematical formula that the previous numbers of the VIN are not fake.

Position 10 represents the SL’s model year with an alphanumeric code. It should not be confused with the year the car was actually delivered or sold. “X” was used for 1997, so “Z” stands for 1999. After the alphabet had been used, the code was switched to digits. “1” for 2000 or “9” for 2008. Then it started again with the alphabet, our “D” stands therefore for 2012.

As already mentioned, the year can also be seen at the top right side of the certification tag.

Position 11 identifies the plant, where the car was manufactured. In our case, it is letter “F”, which stands like all letters from F to H for the plant in Bremen. Letters A to E were used for the plant in Stuttgart-Sindelfingen.

Positions 12-17 indicate part of the chassis number and the order in which the SL has left the assembly line. This is independent of the car’s engine.

These last six digits of the chassis number are perhaps the most critical numbers. Due to possible mid-year production changes, they are vital in identifying the proper part numbers. Such parts are often listed with the caveat that they fit R231 models up to a particular VIN or before or after a VIN sequence.

If we use this particular US-bound VIN, the respective FIN for that car would look as follows:

WDDJK7DA2DF418480

changes into:

WDD231473DF418480

As one can see, FINs for cars outside the US start after the manufacturer’s code with the type of car, followed by the version, which is in our case for the SL500/550 “473”. More explanations on the chassis prefixes one can find a bit later in this chapter. The remaining digits have the same meaning as on the US-bound vehicles.

The certification tag of the R231 does not contain any information regarding the interior or features/extras of the car. There are various sites on the internet, where, after insertion of the VIN, exact data on a particular car’s equipment will be given. Information about the paint and a car’s specific equipment can usually be found on the data card that came with the car, when it was new. On earlier Mercedes models a plate with respective paint and body information was located prominently on the right side of the radiator cross support. As we have seen, with the R231 and other newer models, this is now different.

This chapter is a good place to list the respective internal code numbers of all R231 versions. The facelifted 2016 cars (launched as 2017 models) share the same chassis and engine codes, that is why they are not listed separately:

SL350 R231, built from January 2012 to December 2015:

Chassis prefix: 231.457, engine M276 DES 35, prefix: 276.954

SL400 R231, built from June 2014 to June 2020:

Chassis prefix: 231.465, engine M276 E30 DEH LA, prefix: 276.825

SL450 R231, built from April 2016 to June 2020:

Chassis prefix: 231.466, engine M276 E30 DEH LA, prefix: 276.825

SL500/550 R231, built from January 2012 to June 2020:

Chassis prefix: 231.473, engine M278 DE LA46, prefix: 278.927

SL63 AMG R231, built from February 2012 to May 2019:

Chassis prefix: 231.474, engine M157 DE 55 LA, prefix: 157.983

SL65 AMG R231, built from June 2012 to July 2018:

Chassis prefix: 231.479, engine M279 KE 60 LA, prefix: 279.981

The R231’s data card

The Owner’s Manual and Service Booklet should ideally still be with the car, as they contain two data cards. One of these cards contains the key codes and should definitely NOT be stored in your car. The second one does not contain this information and should be kept in the car, as it helps the technician in the service facility to order the correct parts.

The data card has codes for the original equipment and additional extras that came with the car. Everything printed on it is in German, so on another page it offers some translations and space for the owner to write down his name, address etc. If the car`s data card is lost, one of the DB- or SL-enthusiast websites could be of assistance. Search those sites for key words such as “Factory Option Codes” or “Data Card”. That will lead you to fellow enthusiasts, who might be able to help retrieving the data codes from the VIN of your car. Another option to retrieve those data can be a drive to your DB-dealer or a Mercedes specialist shop. Knowing with what options your car had left the assembly line might be helpful, when ordering parts for it. Sometimes you will find that the optional extras, your SL should have come with, are not there anymore or you have options that were added at a later stage by a previous owner.

A sample data card from an SL500

The upper half of the data card carries 40 number spaces (as one can see on the next page, not all of them are filled out). They show from the chassis-, order-, production-, transmission- numbers etc. all basic information that is important to your specific vehicle. As the codes on the data card might be a bit difficult to read in a book, we will look at them box by box. In case you find this subject a bit too boring, please skip it and go to the next chapter that deals with the car’s COMAND system. We start with the upper part of the data card, left side: Again, this data card is not from an actual SL and should only serve as reference

Box 2, which contains the VIN, does not need to be explained again.

Box 3 shows the engine number, which follows more or less the same logic as the chassis no or VIN. It starts with 278 for the type of engine, which is followed by the specific engine version.

The M278 power plant is a family of direct injected, bi-turbocharged, V8 gasoline piston engines, which started life in 2011 in the S- and CLS class of Mercedes cars. The seventh digit identifies “1” lhd or “2” rhd cars, while the eighth digit shows the engine mounted to a car with “0” manual or “2” automatic transmission. In case you wonder, why “0” and not “1” was used for the manual car, the “1” had been used in the late 1950s for the “Hydrak-system”.

The last six digits show that in our case the engine was the 127,232nd one produced. They are sequential by transmission type, so counted separately for manual and automatic versions in case of cars that offered such a choice.

Box 5 shows the “Auftrags-Nr” or order no. It is one of the most interesting codes of the data card and consists of ten digits. The second digit indicates the last digit of the year the car was ordered, in our case 2015.

The next three digits show, which dealer/country has placed the order for that car. If the code starts with a “2” or “3”, it shows that the car was ordered by a Mercedes subsidiary (or its affiliate) in Germany. Then the following two digits determine together with the “2” the region and dealer.

Our sample car shows the region code “212”, which meant that it was ordered by the Mercedes subsidiary in Berlin. In case of places outside Germany, a “5” as first digit means countries in other parts of Europe. A “537” means the UK, “531” France, “577” Spain or “543” Italy for example.

Countries in the Americas start with a “7”. If followed by “03” to “07” they were destined for the US (for a short time until 1965 also codes 708 to 718 were used for the US).

As a side note, an interesting number is “707” as it means that this particular car was bought through a so-called European Delivery Program, which was quite popular in the 1960s and 1970s. Canada uses code “701”. The Austral-Pacific region starts with a “9” (901 for Australia, 919 for NZ), while markets in Asia have an “8” as first of these three digits (Japan: 839, Hong Kong: 823).

The remaining four digits are sequential for that particular region/dealer and that year.

Box 6 indicates the “Prod.-Nr.” or “Produktions-Nummer”, which is the car’s production number

Box 7 shows the transmission number, which is also stamped inside the bell-housing.

The upper middle and right side of the data card offer in comparison usually relatively little information, although there is in theory plenty of space for all kind of equipment. Alone the first four boxes 11 to 14 can be used for tire-related information, which shows that cards like this are being used for all kind of Mercedes vehicles, from the Unimog to the largest truck.

The remaining boxes 15 to 20 can provide info regarding heating, rims, lights (usually Bosch or Hella), wipers down to winches and speedometers.

The upper center part starts with four boxes reserved for front and rear axles. Box 25 is the “Aufbau-Nr.” or body number and not filled-out in our example. It was necessary during the production process to link all the parts before they finally became a complete car and before a “VIN” was assigned to the vehicle.

One can see this number also on various other parts such as hood, trunk lid or inner side of doors panels for example. This code was always part of the data card on older cars, now it is used primarily for trucks. That is why the name “Fahrerhaus” (driver cabin) has been added.

The same applies to box 26, where “Pritsche” is the German word for flat-bed. The next three boxes 27 to 29 cover the VIN, towbar (Anhänger-kupplung) and steering (Lenkung). The steering – box was also always filled out on older data cards, now it does not seem to be needed anymore, at least not for passenger cars.

Box 30 indicates the “Ausstattung” or interior choice. If that number starts with a “2” like in our case, the interior comes in leather; a “1” would stand for an MB-Tex interior, while a “0” means fabric upholstery, both not available in our SL case.

Box 31 at the top right side shows the paint code.

The lower portion of the data card shows all options that were ordered for the car, when new. Most of these codes have seen over the years numerous assignments. In case of modern Mercedes cars, the first code “220” to the left stands for the Parktronic feature. Earlier it was used for rear door contacts. Also code “284” is a good example. Now it shows the gear lever in wood/leather combination. In the 1960s and 1970s, it was used for a five-piece luggage set. A more drastic example would be code “317”, which was used for the Comfort Package. Quite a few years back that code was used for cars that were sent to Portugal as driver’s school vehicles and thus as used cars most probably best to be avoided. In rare cases, these codes have seen new assignments even during production of a certain model, as has happened with the R107 during its relatively long production.

The COMAND system

The name “COMAND” covers all infotainment systems of Daimler-Benz since 1993 and had been used first in the W140 S-class. Its first name was “Communications-and Navigations-System” and was the first fully integrated telematic-system in the automotive industry.

In 1998, the name COMAND had been adopted. It stands for “Cockpit Management and Data System” and was upgraded continuously over the years. The first such system was the COMAND 2.5 and was produced together with its successor COMAND 2.0 and COMAND 2.0 MOPF by Blaupunkt/Bosch. A key feature of all COMAND systems is to provide full integration between the various functions such as multimedia, navigation and telephony and to also allow multiple presentation and control facilities.

The SL R231, produced from March 2012 to September 2015, started with COMAND NTG 4.5 (NTG = New Telematic Generation), which was first introduced in 2011 in the updated C-Class (W204) under the new name “COMAND Online”. It was a TFT color display with a 17.8 cm (7 inch) display diagonal and a resolution of 800×480 pixels. The radio had an RDS/double tuner and TMC tuner as well as a traffic radio decoder (TP/TA). Drives included a DVD/CD combination drive and an SD memory card slot (previously PCMCIA slot). The MUSIC REGISTER for compressed audio files in MP3 and WMA format was increased for this system by 4 GB to now 10 GB. A USB and AUX-IN port was located in the center console storage compartment. Another new feature was a speed limit assistant, which used a camera to detect signposted speed limits, compared them with the navigation map data and displayed them on the screen. The Comand system was standard for the SL500 and the AMG models, optional for the SL350/400.

Music could be stored on a 10GB hard drive

For Japan, Comand Online was standard with DVD drive (code 527), for North America, Comand Online included a six-disc DVD changer and HD radio (code 512). For the rest of the world, which included the UK and Continental Europe, Comand came standard with a DVD drive and without navigation (code 526). When Comand Online was installed, also the six-disc DVD changer was included (code 512, like for North America)

Another innovation was the system's online functionality, i.e. when the car was stationary, the Internet could be used via web browser. In addition, three services were included, which could also be used while driving: Weather service, Google search (any destinations could be searched and then navigated to) and routes and destinations (from the Internet, for example via Google Maps, a destination or a route could be sent directly to the car). Web radio was also possible (TuneIn login was supported, but it also worked without) For online functionality, the connection via Bluetooth to a cell phone using the DialUp Networking Profile (DUN) was necessary or the Personal Area Network Profile (PAN).

With the help of the optional Mercedes telephone module, COMAND Online could be equipped with an integrated UMTS telephone module with a card slot for a SIM card. All SL cars produced after October 2015 came equipped with the newer NTG 5.0 system, which was seen first in the 2013 W222 S-class. Since NTG 4.5, the Comand was equipped with "Live Traffic Information", which processed real-time traffic data from TomTom.

However, the Comand NTG 5 also only handled the spatial resolution of the BASt table from TMC, at least in Germany, so that reports that were actually available about traffic jams or road closures outside of the autobahns and federal highways often could not be displayed.

With the Smartphone Integration package compatible smartphones could be integrated into the vehicle via Apple CarPlay and used via voice-operated control for example. In addition, the other vehicle controls could also be used. In the case of Apple CarPlay for example, the system supported making and receiving calls, navigation and listening to music, receiving and sending text messages and emails as well as Siri voice control. The selected apps from third-party providers that were also supported included Stitcher Radio and Spotify.

A feature only indirectly related to the COMAND device was “Mbrace”. Introduced towards the end of 2009, it came in two different, annually renewable options, which combined advanced GPS technology with 24-hour support. Both packages covered various convenience and emergency functions, such as Roadside Assist, SOS emergency calls, stolen vehicle location assistance, valet protect (via mobile app), vehicle info, vehicle finder, remote door lock/unlock etc. A new Drive2Friend feature would let other people send their location to your car simply by responding to a text message you had previously sent them.

In addition, you could forward addresses from a smartphone or computer directly to the SL’s COMAND system using the Send2Benz website. You could also look up a destination on Google Map for example and instantly send it to the car via the Search & Send feature. And a new browser toolbar widget would let you highlight an address on your computer/smartphone screen and sent it to your vehicle with just two clicks.

Of course, the screen could also be used for various car-specific functions

Mercedes mbrace was only available to US customers

The mbrace PLUS Package offered on top of this the unlimited use of an expert concierge service, as well as spoken turn-by-turn route assistance. It included also the latest traffic and weather reports based on the SL’s current location.

While Mercedes was quite successful with mbrace in the US, it was not available for other markets. That should change in early 2014, when Dr. Zetsche presented at the Geneva Auto Show a project called “Mercedes me”, a so-called COM module. COM stood for communication, well, how could it be otherwise. In itself, it was not that new, because for some time Mercedes vehicles with the SA COMAND Online (531) already had such a COM module. It was able to autonomously send an emergency call in case of an accident.

With the new 2016 E-class W212 series, this NTG 5.1 version was finally also introduced in the upgraded R231. With it, the 10 GB music register was dropped. Thanks to the standard-fit communications module (on-board SIM card), internet connection was now always on. The functionality of COMAND Online included internet radio as well as Live Traffic Information, for example. The latter service used real-time traffic data for dynamic route guidance with more accurate arrival times.

The “always on” feature enabled the use of the “Mercedes me” connect services. The available standard services included Accident Recovery, Breakdown Management and Maintenance Management, as well as Telediagnostics, for example. Also available as standard was the Mercedes emergency call system. In an accident this service automatically connected the occupants with the Mercedes Emergency Call Centre and sent the position and status of the vehicle to the rescue operations center. The system worked automatically, but could also be triggered manually. All costs related to the connection of the vehicle to the Mercedes server and back were borne by Daimler AG - a bargain when you hear that the offer was installed as standard with SA COMAND online and cost €150 with Audio 20. The term was three years from initial registration, it could be extended for one year at a time.

Extras and option packages

Daimler AG had various options for different countries and to include them all in this book would make reading somewhat tiresome. Some packages that were offered for cars sold in North America were with a few exceptions not sold in other countries, as they were marketed there in different package combinations or even as individual options. This chapter will concentrate on the packages that were sold in either North America, the UK or Continental Europe. Some of them have already been mentioned earlier in this book and some became only available with the upgrade (MOPF) in 2016.

Let us start with the optional assistance packages:

Speed Limit Assist was part of the optional COMAND Online Package. It featured a windshield-mounted camera that permanently scanned the car’s surroundings. It was able to recognize signed speed limits and indicate the detected maximum speed to the driver in the display. The driver could therefore check the prevailing speed limit. This added convenience was of particular benefit on routes with variable speed limits or roadworks.

Active Parking Assist, which included PARKTRONIC. At a speed below 36 km/h (22.4 mph) the car looked for a suitable parking space and automatically entered this space at the press of a button, whilst the driver merely operated the accelerator pedal and brake. If the driver did not wish to use Active Parking Assist, the PARKTRONIC electronic parking assistance system monitored the front and rear area while the driver was maneuvering the vehicle and warned the driver if a risk of collision was detected. In some markets, such as Canada and the US, this feature was part of the standard equipment.

Lane Keeping Assist. This feature was/is not universally liked and many drivers (like the author) try to turn it off permanently. It warned the driver via steering wheel vibrations as soon as it detected that the vehicle was leaving its lane unintentionally (or you forgot to set the indicator, when overtaking). This was possible thanks to a camera on the inside of the windshield which films the road. The warning was not given if the driver accelerated, for example, before an overtaking maneuver or when driving onto the motorway, if they braked sharply or steered into a bend. Most modern cars go one step further: they do not only let the steering wheel vibrate, they even force you back into your previous lane, in case, as mentioned a few lines earlier, you have forgotten to set the indicator.

One of the most popular extras in Europe was the AMG Sports Package, in North America it was called AMG Line Package. In the UK it was part of the standard equipment. Hence the SL was sold there as SL400 Sport and SL500 Sport. The exterior package should emphasize the sportiness of the roadster. The AMG body-styling came with front and rear aprons and side sill panels. AMG light-alloy wheels with 255/35 R 19 tires at the front and 285/30 R 19 at the rear helped to enhance the overall look. The standard 7G-TRONIC PLUS transmission had shift points optimized for sporty performance in the S transmission mode. The sports suspension was lowered by 10 millimeters (NOT in the US). The customer could choose between high-sheen 5-spoke light-alloys or high-sheen 7-twin-spoke light-alloy wheels, finished in titanium grey. Part of the package was a tauter spring response and damping setup (de-selectable, not with Active Body Control ABC). The uprated braking system offered perforated brake discs also at the rear and “Mercedes-Benz” lettering on the grey-painted brake calipers.

The characteristic AMG Line was then continued in the car’s interior. Appointments and equip-ment specific to this package included the instrument cluster with its “Chequered Flag” design, the sports steering wheel with a flattened bottom section as well as silver-colored shift paddles and perforated leather in the grip area, and the sports seats with their vertical fluting which were available in leather, nappa leather or Exclusive nappa leather (black and perforated in each case). White piping on the door armrests, center console, seat side bolsters and head restraints provided an attractive contrast. The trim was available in a choice of light or dark longitudinal-grain aluminum. AMG floor mats were another feature of this package.

The optional Multi-Contour Seats should relieve the load on the spinal column and could be adjusted to meet the ergonomic requirements of both driver and passenger. The pressure in the variable air cushions in the side bolsters of the backrests could be adjusted, as could the backrest curvature in the lumbar and shoulder regions. Another option was the active multi-contour seat, which adjusted continuously to the changing lateral acceleration forces, massages the back muscles and could reduce the risk of injury in an accident.

The seat heating was standard from SL500/550 onwards and optional for the V6 cars. It allowed heating of each seat to three different levels, plus the heating distribution between the seat and the backrest could be varied too. The optional climatized seats featured fans that were integrated in the upholstery. The air flowed through the perforation and helped to cool down the surface of the seats to a lower temperature – even if the car had been heated by intense sunlight for a longer period of time. Sun-reflecting leather was standard in conjunction with leather, nappa leather and Exclusive nappa leather except designo leather.

As an optional extra the SLʼs seats were available with an additional coating which reflected heat. This prevented the seats from heating up in intense sunlight – bringing extra comfort, particularly when the vehicle was open. Saddle brown was a newly available option available with the 2016 update in combination with Nappa leather and Exclusive Nappa leather.

Other comfort-oriented options were the Airscarf #403 (included in Premium Package #P01) and the electronic Draft Stop. The neck-level heating extended the open-air season. At the touch of a button air was wrapped around the shoulders and neck of the driver and passenger like a warming scarf. In order to achieve this effect, the system drew in cold air before warming it and releasing it again through vents in the head restraints. When driving with the roof down, the electrically operated draught-stop ensured optimum protection from draughts if the driver or passenger touched a button on the center console. The fine-mesh textile fabric covering the frame kept the passenger area almost entirely free of draughts.

Another option that could be seen to enhance the comfort of driver and passenger was the Magic Sky Control #412 in the vario-roof. The roof changed color at the touch of a button from dark to transparent and vice-versa in a matter of seconds. In this way the driver and passenger could enjoy a view of the sky even when the roof was closed. And when the glass was darkened, the vehicle interior heated up considerably less.

A manually operated roller blind, also optional, offered even more protection from the sun when required.

A further comfort feature was the optional Keyless-Go Convenience Package with Hands-Free Access. There was no need to have the key in your hand to open the car or start the engine. If you had the Keyless-Gg key with you, all you had to do was operate the door handle. The car was started by simply pressing the start/stop button. The Hands-Free Access convenience function made loading and unloading the trunk easier by using a sensor to trigger automatic opening or closing of the trunk lid, when the driverʼs foot was detected beneath the rear of the vehicle.

Some of the above-mentioned features were also available in other packages, such as the Premium Package #P01, which was standard in North America on the SL550, in 2019 also for the SL450.

It came with:

-          Rearview camera

-          Parking pilot

-          Heated and active ventilated front seats

-          Airscarf

-          Active multi-contour seats with massage function

-          Electronic trunk closer

-          Keyless go with hands-free access

-          grey painted brake calipers and perforated brake disks

If you did not like the AMG line package, but still wanted the AMG wheels, you could opt for the Sport Wheel Package #321, which included:

-          Sport Package Brake System

-          19” AMG 5-Spoke Wheels

-          Sport Steering Wheel

Nice looking 19” 5-spoke AMG wheels were part of the Sport Wheel Package

An AMG Carbon Fiber Package #773 was available for the SL63 and SL65. It included:

-          Carbon Fiber side mirror covers

-          Carbon Fiber Trunklid Spoiler

-          Carbon Fiber Front Bumper Cross Strut

The Driver Assistance Package #997 (standard on the SL65, required P01) consisted of:

-          Distance Pilot Distronic with steering pilot

-          Cross-Traffic Assist

-          Active Blind Spot Assist

-          Active Lane Keeping Assist

-          Pre-Safe Plus

-          Active Brake Assist with Cross-Traffic Function

-          Bas Plus

-          Collision mitigation (Pre-Safe Brake)  

Another option was Ambient Lighting, which provided a pleasant indirect lighting effect inside the SL at night. Luminous surfaces on the dashboard, below the door trim and in the rear compartment trim cover created a pleasant atmosphere. The ambient lighting was activated or deactivated with the exterior lighting. It was also switched on when the doors were opened in order to create a “welcome home” effect. It was possible to switch between three ambient lighting colors – solar orange, solar red and solar yellow – which could also be dimmed to emphasize the SL’s interior design. After the 2016 update and in addition to solar red, the colors polar blue and polar white could also be chosen.

It was second nature for Mercedes to include many safety systems standard. While features like Intelligent Light System, Magic Vison Control, Active Brake Assist or Attention Assist were all standard equipment, some of the “finer” add-ons were only available as options. One of them was Adaptive High-Beam Assist. Taking into account oncoming traffic and vehicles in front, the system ensured that the illumination of the road and distance vision were significantly improved. The range of the low-beam headlamps was automatically adjusted to the amount of traffic on the road. In practice it meant, you could just switch to high-beam and forget about the rest. This function was active from a speed of 30 km/h on roads without street lighting.

The Adaptive Highbeam Assist selected optimum light settings automatically

Another optional safety feature was Night View Assist Plus #610. This system detected people, animals and objects up to 160 meters ahead on the road, using two LED infrared headlamps and a thermal imaging camera. When the system was activated, the night vision was automatically switched on in certain relevant situations and was only switched off again once the car had passed the hazardous situation. The people and animals detected were highlighted on the screen.

The optional Intelligent Drive Package #IDP with stereo camera offered after the 2016 update some improved functions. Key components of the Intelligent Drive package included:

- Distronic Plus with Steering Assist and Active Lane Keeping Assist (both features were already discussed earlier in this chapter). The Active Brake Assist with cross-traffic function was able to warn the driver of impending crash situations, provided support with emergency braking and, if necessary, also automatically applied the brakes itself. In addition to detecting slower-moving, stopping or stationary vehicles, it also detected crossing traffic at junctions, the tail end of traffic jams and pedestrians in the danger zone ahead of the SL.

-.The Pre-Safe Brake was able to detect not only slower-moving, stopping or stationary cars, but also pedestrians to brake autonomously if the driver failed to react. As a result, it helped to avoid accidents up to 50 km/h and reduced their severity up to 70 km/h. In flowing traffic, the Pre-Safe Brake provided assistance throughout a speed range from 7 to 200 km/h.

-.The Active Blind Spot Assist was able to warn the driver when changing lanes, and could contribute to averting an impending collision by means of one-sided brake actuation.

-.Pre-Safe Plus was activated, when a rear-end collision appeared imminent, the system could activate preventive measures to protect occupants. These included warning cars following behind and applying the vehicle brakes when at a standstill.

The Night View Assist Plus came with new functions for highlighting pedestrians on the display

Updates and facelift (MOPF) overview

Most of the updates have been mentioned already in earlier chapters, but it might be beneficial for the reader, to have them all included in a separate chapter for easier reference. A major model enhancements or MOPF (abbreviation of the German word MOdell PFlege) happened just once in the life of the R231. In the US for example, these cars were then sold as next year’s models. In the UK and Continental Europe they were just sold as models of the year in which they had received the update.

But minor updates were also seen earlier and even up to 2019. These are listed here too. As they did not happen in all markets at the same time, if at all, the author has taken the UK and North America as example, as cars in these markets usually showed similar option packages.

Updates for 2014:

-          Launch of the SL400 in August 2014

-          “Black Diamond Edition” - 400 units of SL550 (US only)

-          6 Disc CD/DVD Changer was canceled

-          3 rear tweeters were canceled from standard Harman Kardon sound system (now there were a total of 11 speakers, not 14)

-          ISO-symbol on Eco Start/Stop switch

-          3 years of Navigation Map Updates were included as standard equipment (US only)

-          SL63 - P30 Performance Package was canceled, however, the following components were made standard with no price increase: rear axle limited differential, increased power output to 557 hp/664 lb-ft. torque, and top speed raised to 186 mph (US only)

-          Red painted brake calipers and AMG steering wheel with DINAMICA grips became available for the SL63

Updates for 2015:

-          SL500/550 power increased from 429 hp to 449 hp

-          New paint Selenite Grey (992) replaced Palladium Silver (792) and Steel Grey (755)

-          5 years of mbrace services as standard equipment, with three new mbrace upgrade packages available (US only)

-          Exterior Carbon Fiber package became available for SL63 and SL65 for $3,570

Changes (MOPF) for 2016 on cars built after the end of 2015:

Exterior

-          New front design from A-pillar forward

-          Diamond grille in silver for SL450/SL550

-          New engine hood, front fender and air outlets

-          New rear bumper

-          Full LED head- and tail-lamps, tail lights completely in red

Interior

-          New flat-bottom steering wheel

-          Redesigned steering wheel center covered with nappa leather

-          New design for instrument cluster, up to 60 km/h, the speed scale was indicated in increments of 10 km. When starting, the needle moved from the 6 o'clock position once over the entire scale and then returned to the starting position again

-          Upon start-up, the TFT multifunction display between the instruments showed a front view of the SL

-          Telematics generation NTG5.1 with smartphone integration

-          Ambient lighting with 3 colors (solar red, polar white and polar blue)

Standard equipment (this can vary from country to country, vehicles sold in the UK and North America usually came with more standard equipment)

-          New 9G-tronic transmission (AMGs include AMG SPEEDSHIFT 7-speed transmissions)

-          DYNAMIC SELECT driving programs (E, C, S, S+, Individual)

-          Opening of retractable-hard-top (RHT) while driving (up to 40 km/h or 25 mph). It needs to be initiated at speeds below 10 km/h or 6 mph

-          Electric trunk partition

-          Full LED lights front and rear

-          Active braking assist

-          19” wheels instead of 18“ wheels

-          Smartphone Integration with Apple CarPlay

Optional equipment

-          Active Body Control with CURVE function (487) (Curve Tilting SL450/SL550 only)

-          Active Brake Assist with Cross-Traffic Function (269)

-          Distance Pilot DISTRONIC with steering pilot (233)

-          Omission of SPLITVIEW (867) and Night View Assist PLUS (610)

Paints

-          Omission of Lunar Blue (890)

-          Omission of designo Magno Shadow Grey (281)

-          New color: Brilliant Blue (896)

-          New color: designo Selenite Grey Magno (297)

Upholsteries

-          Omission of leather nappa nut brown

-          Exclusive nappa leather upholsteries available (5xx)

-          New upholstery color: leather nappa saddle brown (814)

-          New upholstery color: exclusive nappa leather saddle brown (514)

-          New code: leather crystal grey 208 becomes 218

Trims

-          New trim: light carbon grain aluminum (H42)

Wheels

-          New 19” 5-spoke alloy wheel (R82) – standard for SL450

-          New 19” 10-spoke alloy wheel (R97)

-          New 19” AMG 5-spoke alloy wheels (752) – standard for SL550

-          New 19” AMG multispoke alloy wheel (788)

-          New 19” AMG 10-spoke light alloy wheel (799) – standard for SL63

-          New 19”F/20”R AMG 10-spoke High-polished wheel (659) – SL65

-          New 19”F/20”R AMG Forged wheel options (657, 658) – SL63, SL65

Updates for late 2017, 2018:

-          Logo Projector Lamps added to standard equipment

-          MB star on wheels and above front grille became Black without Laurel

-          Fire Opal Red paint (590) discontinued

-          Rearview Camera (218) for SL400/450 added to standard equipment

Optional equipment

-          AMG Sport Steering Wheel in Leather/DINAMICA (L5I) for SL400/450

-          Seat Belts in Silver (Y04) and Red (Y05)

-          Deletion of Aluminum Trim (739)

-          19" AMG Multi-Spoke Bicolour Wheels (606) added to stand-alone options

-          19" AMG Multi-Spoke Wheels (788) added to stand-alone options

-          Night Package added to stand-alone options

-          Silver brake calipers added to stand alone options (SL65)

Updates for 2019:

-          Mercedes MeConnect was now standard equipment for all models

-          Premium package (P01) was now standard also on the SL400/450

-          A $900 price increase for all models

Exterior highlights for the 2016 MOPF SL400/450 and SL500/550

Exterior highlights for the 2016 MOPF SL63 AMG

Exterior highlights for the 2016 MOPF SL65 AMG  

R231 buyer’s guide

As most owners, who have experienced both the R230 and R231, can confirm, the quality of the first R230s suffered from Daimler-Chrysler’s drive to increase shareholders’ value. The R231, even the first 2012 models, never had any of these quality issues and when searching the internet or asking workshops that deal with the SL, the overall opinion is that R231s are some of the more reliable cars out there.

These big SL are luxurious, heavy and even with the V6 quite sporty. And although they offer a design that quite a few consider not to be one of the best SL designs to come out of Mercedes-Benz, the car has a presence on the road unlike many other, even more expensive cars. The 2016 facelift has improved the design of the car’s front somewhat, so if asked, the author would consider the facelifted SL to be the better one of the pack. However, this is just a purely personal taste and at the end, it depends a lot on how well the car has been maintained.

These cars have been expensive when new and although you can get the first ones now at quite a discount, this does not mean that maintaining them has become any cheaper. It was not cheap nine to ten years ago and it is for sure not cheap today. This does not mean that the R231 needs to have all the Mercedes dealer stamps in its service book. An exception would be for the author the AMG versions.

Nowadays an experienced mechanic in a specialist shop might be as good a bet to send the car to. Parts from MB dealers tend to be much more expensive than parts that a specialist shop might be able to get from other, but still reliable sources. Looking for the one SL can be very rewarding; it can actually be real fun. It can also be quite a challenge and occasionally it can turn out to be a real nightmare. Although not too many have been produced, you can still afford to turn away from a car that is not one hundred percent convincing.

In a nutshell:

Condition is more important than the size of the engine. That is why always prefer a good SL350/400 to a poorer SL500 that offers more extras at the same price.

Modest budget and R231 do not go hand in hand.

If the vario roof does not work flawlessly, walk away!! Don’t accept any silly excuses like: “That is the same case with all other SLs I have seen”.

A cheap (or even slightly neglected) AMG V12 without full MB dealer or similar documentation will ruin you!! 

A few R231 have been “upgraded” by a previous owner with bigger, non-standard alloys and tires. Try to avoid those cars, as they have been driven harder and the expensive to repair ABC suspension (if installed) could have suffered. This will cause unnecessary and potentially expensive repairs.

Check maintenance records for the ABC systems, if installed. Although it appears to be less problematic than on the R230, the early cars are now ten years old. If records cannot be provided and you cannot get any related information from MB or MB dealers for this specific car, do your wallet a favor and look for a better documented alternative.

Later model cars have more standard options than earlier versions. But they are more expensive.

Consider to buy privately from an enthusiast, who understands this kind of car. He has usually also all the maintenance work properly documented and can give you valuable tips. Especially MB dealers seem to be useless with older cars.

Drive a good one that is sold at a specialist shop first, so you get a feeling for what to look out for, when you start your hunt.

Any warranty is a huge plus. Warranties can have a maximum age and mileage, before they start.

Have a $5,000 contingency fund in place, in case you drive the car without warranty.

Driving the SL as second car offers the advantage to do some search for the most appropriate repair solution in case something goes wrong. A daily driver needs to be fixed faster, which is usually more expensive. See again #2.

If you look for a V8 car, do yourself a favor and drive also an SL400/450. You will be positively surprised.

Body:

1. Contrary to older SL, the all-aluminum R231 is very resilient against corrosion, but you should always check the body for any dents. Aluminum panels are expensive to repair.

2. The vario roof should work flawlessly, as its mechanics are costly to replace. A separate chapter of this book looks into this feature a bit more in-depth.

3. Water leaks into the trunk. This can be attributed to clogged hollow seals in the C-pillars. Once the drain holes are cleared, it is advisable to put some sealant around the seal at the C-pillar’s bottom. Another cause can be a faulty lower rear window seal, where the rear of the trunk makes contact. With age it can detach from the frame below the rear window. Or as the seal ages, it will flatten and shrink so it might need to be replaced.

4. Many water leaks have something to do with the roof meeting the body/pillars or the windows. In case of leakages at the A-pillars this can in most cases be stopped by applying a healthy dose of MB Sliding Compound. If this does not help, the leak can be caused by a faulty front lock hydraulic cylinder.

5. Most other leakages, if not related to the windows themselves, can be traced to one or more of the drain holes being clogged.

Just in case you wonder, how many drain holes there are:

-          One at the bottom of the air box intake

-          Two at the rear window, one on each side, where it connects with the C-pillars via flexible tubes

-          Two under the front of the trunk lid, one on each side

-          One at the bottom of the trunk in the wheel well

-          Two under the panel at the bottom of the windshield, one on each side

Depending on where you live, one issue can be leaf mulch collecting in the heater box drain outlet. It should be cleared regularly so that no water can come inside the car.

6. If the car that you inspect is at a location, where it can be lifted, do yourself a favor and actually ask, whether you can inspect the car from underneath for any damages to the suspension for example.

7. Open and close doors, trunk, hood and check for any leaks, worn out hinges, lack of support, etc. Check at the same time, whether all badges/emblems are still in place.

8. Check if both bi-xenon headlights have the same intensity (Pre-MOPF cars only).

9. Ask, whether the car had an accident and if yes, was it repaired at an authorized service site such as the DB-dealer. Especially rear damage can be troublesome for the vario-roof, if not properly repaired. If in question, walk away from that particular car, there are plenty others available.

And if possible it should look from underneath like this well maintained 2017 R231

Engines, transmission:

1. The good news is that all engines are known for their superior reliability, when regularly serviced. That is why it is important to look for cars that have proper service records. Try to look at a car when its engine is cold. Poor cold starting can be attributed to a host of problems, many of them linked to the expensive to replace ECU and fuel injection. Don’t be fooled by statements that the car has not been moved for a long time.

2. In its early production cycle, some drivers with the V6 M276, V8 M278 and AMG V8 M157 engine experienced cold start rattling noises that could last for a couple of seconds. Apparently, the secondary chain tensioners produced a rattling noise until the engine oil pressure had built up. According to Mercedes, no consequential damage was to be expected.

The following engines were affected:

Engine 157: Up to engine 1579xx 60 047752

Engine 2768: Up to engine 2768xx 30 001281

Engine 2769: Up to engine 2769xx 30 406603

Engine 278: Up to engine 2789xx 30 191843

In December 2015 Mercedes-Benz issued a service bulletin (LI05.10-P-056435, version 10) and instructed its dealers to replace the secondary chain tensioners on the left and right side and to install a check valve in the oil supply bore of each secondary chain tensioner in the cylinder head on left and right.

3. On January 9th 2022 Mercedes-Benz issued a recall with code 792034: A trapped particle may damage the sealing between the fuel rail and fuel injector, which could cause fuel to leak into the engine compartment. Consequently, leaking fuel may come into contact with hot parts of the engine, increasing the risk of fire.

The SL vehicles affected by this recall were manufactured between May 27th 2016 and August 24th 2020.

The V12 combines unrivaled performance with grand tourer luxury

4. The power plants were engineered to high standards and can tolerate a lot of abuse, despite their somewhat complex design. Still check for any oil leakage. On rare occasions the V8 M278 engine would turn over, but not start. Or it would run rough, almost like coughing. Even worse, it suddenly stalls and only starts after some time again. Cases like these are usually related to a faulty crankshaft sensor.

5. Cars that have driven over 100,000 miles might require new head gaskets. Those gaskets do not just disintegrate, they corrode over time and start to leak. One way to avoid this is to keep the coolant fresh. This should be done at least every three years. If you will do it, buy original coolant from your DB-dealer, it is not expensive.

6. The V12 M279 engine is almost bullet-proof. It is expensive to maintain though and while most first owners have followed established service intervals, some second or third owners might have skimped a few of them to save on costs. If you are really after the V12, a service booklet with all proper stamps should not be good enough. The author would want to see all the bills that match the booklet. Also, all MOT/TUV documents should be provided.

7. Check, whether the V12 engine produces any ticking noises when at idle. This comes usually from a cylinder bank and means that there is an expensive issue with the pistons. Other problems with a cylinder bank can result in a complete shutdown. Usually that cylinder side’s catalytic converter is clogged and the bank cannot breathe, causing the turbo not to work properly. Because of the misfires, the engine tries to protect itself and switches into limp mode.

As all of this is very costly, it is best to bring the car to your nearest MB or other trusted service facility, before you buy it and have the engine codes checked.

8. This brings us to another subject with the V12: please make first sure that there is a workshop not too far from your home, which understands these wonderful engines. Again, it does not have to be an authorized MB-dealer, sometimes with these engines, it is (also for your wallet) even better, if it is not.

The drive belts should be carefully checked for tension and wear They should have been replaced on cars with over 60,000 miles or 100,000 km on the clock

All rubber-hose connections should be tight and free of leakage

9. One possible reason for older engines to malfunction is the engine wiring harness; over time the insulation can break down inside the loom. This might not be the case yet in 2022, but once our R231s get older, it is bound to happen. Symptoms can be hard running of the engine and/or the “check engine” light coming on. A new harness is expensive, but usually it can be installed in less than two hours.

10. Higher than normal cooling water temperatures can be attributed to either a lack of coolant or more often a malfunction of the engine fan’s viscous coupling. This will degrade over time, start to slip at higher rpms and then supply the engine with less than sufficient air. Eventually the radiator overheats and its headers crack.

11. Automatic transmission and rear axle differential should be checked for oil leakage or noise.

12. Ask the previous owner, when transmission fluid had been changed. It should be done every 25,000 mi / 40,000 km on a warm engine or alternatively every five years.

13. If the transmission or differential is noisy, this can be attributed to either worn or wrongly inflated tires. Check also how the gear lever changes from Neutral to Drive, Park etc. If there is a problem with a clean shift, it can mean that the plastic part that stops the gear from being shifted into reverse without the driver’s foot on the brake pedal, is about to fall apart.

14. Sometimes the transmission locks itself in “Park”. In that case, the gear selector mechanism has to be replaced.

15. Not directly related to the engine, but somehow connected is the fuel pump. If you detect any leaks from the fuel tank, the reason is mostly a defective pump. Listen for ticking noises from it. It can be a sign that the pump needs to be observed and eventually replaced.

Suspension (ABC system):

The fully active suspension system ABC is fitted standard on both AMG SLs and was a popular extra with the non-AMG V8 and on occasions also the V6 versions. It was first seen on the C215 in 1999 and is despite its somewhat questionable image a very reliable feature, if it has been regularly maintained. Older R231s have by now reached an age, where neglected systems will show signs of leakages in the soft and hard lines, which by the way are subjected to pressures as high as 3,000 psi.

Age and minimal maintenance can also cause corrosion around its pipes. So before buying an ABC-equipped R231, have those pipes checked carefully. Corrosion will eventually cause leaks and if the fluid level is below a certain level, the expensive to replace ABC hydraulic pump can run dry and needs to be replaced, in many cases together with the struts and valve units. The pump’s fluid level should be checked when the trunk is empty, the fuel tank is full, and the car is parked on a level surface. Otherwise, the reading might be incorrect.

There is one BIG CAVEAT: before you check the fluid yourself, please make sure that the area around the dip stick is absolutely clean. Dirt particles entering the system are its death-knell. By the way, the most common debris in the system is usually small pieces of rubber from the solenoid valves and accumulators. These seals can degrade due to age and the extreme pressure generated by the system. The debris will stick to the plunger or seat of the valves that control the suspension.

Mercedes-Benz does not encourage SL owners to check the oil level themselves. Instead, they advise that if a warning is displayed in the instrument cluster, you should visit the nearest MB dealer. When the ABC warning light comes on, the suspension is in a limp mode, and valves to the struts are locked closed. That way, a leaking strut will not cause the other struts to leak down.

Just in case you are curious, this is how the pump looks like

The non-AMG SL had ABC only as an option (in Canada, also the SL550 had ABC as standard). The author estimates that not more than 8-10% of V6 and 15-20% of V8 models produced were ordered with the ABC system

If the new owner of an older R231 does not know how well his prized possession has been maintained in its previous life, a preventive fluid and filter change should be discussed with your mechanic.

The hydraulic pump has a very fine/tight micron filter inside the reservoir that should prevent finer dirt particles from reaching the valve blocks. It is connected to the cap and has a cylindrical shape. The filters have a metal cage to hold the fleece and are 3 microns. A normal oil filter can filter out particles that are around 30 to 40 microns in size. Therefore, when changing fluid, it is a good chance to check at the same time the filter and eventually replace it with a new one. This is much cheaper than having to replace the hydraulic pump at a later stage. Some owners change the fluid every 25,000 mi / 40,000 km or every three to four years.

The reason is that our SL is usually not driven anymore as everyday car, in some cases not driven in winter at all. This means the car stands in a cold garage for an extended period of time.

The whole system uses some 4.5 liters of Pentosin oil or Pentosin CHF11S. Pentosin oil is like all oils hygroscopic and can/will accumulate moisture. This in turn can be responsible for corrosion within the system, causing among other expensive scenarios the hydraulic pump to fail. Failure of the pump might not, but can cause (as already mentioned earlier) small metal particles from the destroyed pump to be pushed through the entire ABC system. In this case and before the whole ABC suspension will become a total loss, it is recommended that everything has to be disassembled, carefully flushed and cleaned manually.

The fluid quality can be checked with the dipstick from the reservoir. Just place some of the fluid that is attached to the stick onto a white piece of cloth. If it is green, everything is fine, even if the fluid shows a slight brownish color, it is still in fair condition, but should be watched. However, as soon as it turns dark brown it is a sure sign that it needs to be replaced immediately. In this state, it is already mixed with tiny metal debris particles, which act like liquid sandpaper.

It is not possible to flush all of the fluid in one go, as around one liter will always remain in the spring reservoirs. So, either you accept that a small percent of old will mix with a large percent of new or alternatively you raise and lower the suspension a couple of times (rodeo mode) and perform another flush and oil change. The rodeo mode/test comes also into play in order to bleed air out of the system. In the Diagnostic Tool, you can do this by going to “Control Units” -> “ABC Control Unit” -> “Activations” -> “Rodeo Test”.

If you or your trusted mechanic find water in the system, you will need to get rid of all the fluid in one single go. In this case, it must be blown out of the system with compressed air. This is a rare scenario, but if it happens, also the pump needs to be taken out and fully drained.

After around 150,000 km )93,000 miles), you should consider replacement of the accumulators and a rebuilt of the valve blocks. With all this done, the ABC can be safely considered an almost trouble-free feature that should be good for some 300,000 km or more with regular maintenance. Talking about accumulators, there are three of them on ABC-equipped vehicles. Each valve block has an accumulator along with the return line. Each accumulator has a diaphragm with hydraulic fluid on one side and high-pressure nitrogen on the other. The accumulator supplements the pressure and fluid volume provided by the pump in cases where the suspension has to do a large correction.

The ABC system can develop noise issues that can sound like a power steering failure. It is usually a humming or howling noise that can come from under the car. It is typically heard at idle up to 2,000 rpm. This failure can occur on cars with more than 100,000 km. The most common cause is the pulsation dampener that is typically found on the line going from the pump to the front solenoid block. This dampener is engineered to smooth out the pressure changes caused by the pump and movement of the suspension. Another cause for the noise could be a failed or about to fail accumulator, or, and simple to repair, a loose hydraulic line that is in contact with the car’s body.

The color of the ABC fault message text is also important. White or blue means that the warning is not critical, and you should be able to continue driving. Red indicates a critical problem. It is unsafe to continue driving the car. If you continue and if the car’s height drops to an unacceptable level, the car will display a “Stop, Vehicle Too Low” warning. Driving beyond this point might lead to expensive repairs. If the ABC warning message only appeared when you turned on the ignition and then turned off, the problem could be due to a pressure drop. Once pressure builds up, the ABC warning may turn off. If the ABC warning message persists, then there could be a more serious problem with the ABC system. For further analysis you will need to read the ABC module fault codes with a Mercedes-Benz scanner.

Aside from the ABC system, there is another suspension item that should be checked: if you test drive the car, you plan on buying and hear thumbing or some sort of banging sounds from the front suspension, this can be caused by defect spring control arm rubber bushings. The upper control arms should be checked for faulty rubber covers. If they are not replaced in due time, the ball joints will deteriorate and need replacement. AMG vehicles are usually driven harder than the standard SL, so if you hear a knocking sound under hard acceleration, this can be caused by worn-out engine mounts. Also, on models with the Active Dampening System (ADS), the valving and electric actuator can fail.

Wheels and brakes:

1. Check tires for unusual or uneven wear. This may mean that front or rear wheel tracking is off, which can cause, if neglected over an extended period of time, expensive repairs to either front or rear suspension. It can also be a sign that the previous owner had pushed the car frequently pretty hard or used it often on drives over roads with pot holes. Another sign of a previously hard life for the car can be unusual wear of brake rotors and/or brake pad linings.

2. Do alloys have scratched rim edges. If yes, it is mostly a cosmetic issue. Question is can you live with this?

3. Check for worn-out ball joints: grab each tire with both hands and push from side to side (while tire is out of contact with the ground). They should not have any major movement.

4. Drive the car on an empty road at a speed of 6-9 mph / 10-15 km/h, then gently apply the brakes with your hands lightly on the steering wheel. The R231 should hold its course without moving to one side. If not, the brake pads need replacement in most cases.

5. Drive the car on an empty road again and brake hard with both hands this time firmly on the steering wheel. If you can hear any knocking sound, the front suspension rubbers need replacement. This is a more common issue with cars whose odometer reading exceeds 50,000 mi / 80,000km.

6. Check the tailpipes for soot. If they are oily, it could mean that the rings are worn.

7. An issue unrelated to a faulty tire is the car’s ride. Should you have a non-ABC equipped car and find the ride too harsh, this is usually caused by the standard run flat tires, especially in 19” or larger size. A remedy is not cheap, but the author has read in a couple of discussions on the internet that if you replace them with 18” wheels and non-run flat tires, you will notice a significant ride comfort improvement. Also, “All Season” type of tires will generally have a sidewall slightly less stiff than that of a “Max Performance” summer tire. By the way, the SL350 came standard with 17” wheels. They might have been even more comfortable, but they did not look very attractive.

While the car is lifted, have the tires removed and check the brakes

Interior:

1. Drive the car through an automated car wash and check for any leakage from the roof or windows, which could mean you have an issue with the hardtop or the windows do not fit precisely. Check also behind the seats for dampness on the floor.

2. When inside the car, check whether all the gauges function properly. Then turn all interior lights off. Switch on exterior lights and turn the dimmer switch on the instrument panel to see, whether the instrument lights are working.

3. Seats are naturally prone to wear, especially around the left side bolsters of the driver’s seat, although the material quality is better than on the R230. Most people will be unable to repair leather properly.

4. Do the electrical seats work in all directions, does the seat memory function.

5. Check the seat heating (the cooling is more difficult to test/feel). If you knee on them in order to clean the car’s interior, the heating system in the seat can break. The previous owner might have done so and it is expensive to repair.

6. Are central locking and alarm function working properly? Their controls are in the trunk, close to the roof’s motor. Leaky seals/water ingress can have affected them.

7. Make sure the air-condition is working! Fan motors can fail and the system can come up with some apparently un-diagnosable leakage. If you live in hot climates, you might then want to reconsider your potential purchase.

On November 22nd 2019 Mercedes-Benz issued a recall for SL cars produced between March 1st 2018 and November 30th 2018. The passenger side airbag cushion has been sewn incorrectly on some cars and it was advised to replace the airbags in affected cars.

Aircon and everything electrical has to work flawlessly

The desirable AirScarf usually works without problems

8. If you are a fan of talking to your car, check whether the Linguatronic can be used. It was not the best system at its time, but much better compared to the R230. Yet it can be confused by surround sound, especially when motoring with the top down.

9. Everything electrical has to function, as repairs in this department can be very expensive.

10. Does COMAND online work, is the screen free of defects and scratches

11. Are the nav data up-to-date

12. Test the audio system with a CD

13. Is the steering wheel adjustment working

14. Is the AirScarf blowing warm air

15. Occasionally, the AirScarf switches itself off after a few minutes. This could mean that the blower motor draws too much current and needs to be replaced

16. Very important: verify the VIN

Trouble-shooting the vario roof

For the potential R231 owner the proper functioning of the vario-roof is one of the most important things to check, before the car will be bought. Although there are very few issues circling the internet or mechanics who report consistent problems coming up on a regular basis, the vario-roof needs to be one of the top items on the to-check list. Next to the actual operation of the roof, you should look for any creaking noises that could point to wrong roof alignments. One way to find this out is to drive the car with the top closed over a few speed bumps, but only with one side of the car. Then do it with the other car’s side. Any rattling or creaking can point to potential or already existing issues that need to be sorted out by a mechanic. One of these causes can be the intermediate bearing bolts of the roof mechanism, which you can actually change yourself with the roof fixed in the semi-open position.

The roof is pushed by a hydraulic pump that is located at the bottom of the trunk under a foam. There are eight hydraulic cylinders and thirteen switches that are involved in the roof operation. As the earlier ones of our SLs are by now ten years old, something with this operation is bound to go eventually wrong. This is especially the case, if the car is driven infrequently or if the roof is rarely operated. The pump itself is a high-quality device that can withstand over 10,000 cycles, but the cylinders are less likely to last that long, as they will start to leak at one point. The picture on the next page shows the location of the cylinders, of which the roof lock cylinder is usually the first one to leak because of decaying seals. This will cause the headliner and eventually also the door trim to get dirty from hydraulic oil. If the roof is slow to operate and you can determine a leak to be the most likely cause, it is usually either the roof lock cylinder, one of the two frame lock cylinder or the trunk lid frame cylinder that is leaking. Of these four, the trunk lid frame cylinder is in most cases the least likely one to go.

This and the following pictures show the R230, but the roof operation is similar on the R231

One possible sign of an otherwise yet undetected leak can be a low fluid level in the pump’s oil reservoir.

If the top stops functioning for whatever reason, the first thing to do is to check, whether the luggage cover is fully closed. Although it will be indicated on the dashboard, whether the luggage cover is fully closed, it does not hurt to release and close it again firmly. Another cause for a malfunctioning top can be the battery in the trunk not being fully charged.

And sometimes, when the top refuses to co-operate, it is the good old-fashioned (gentle) shaking the top back and forth that will possibly remedy the situation, while a second person operates the switch. This might help especially, if the top seals are getting stuck at the windshield frame. A push on the roof near the windshield frame and proper cleaning and applying talcum powder or rubber grease (“Gummi-Pflege” in German) on the seals can be an easy remedy. The status of all thirteen switches is difficult to check. Some are hidden and difficult to reach so this is best and fastest done with STAR diagnosis or a similar device that can read codes.

Basic micro-switch layout

If the switches and their connections seem to be in order, the focus should be on the control module that sits under the right-side storage shelf. As the name implies, the module controls the hydraulic unit (and tells it to change direction of pump motor rotation) and the side window motors. It reads switch position and sensor values and sends function and warning messages. It also controls the wipers, central locking and rear window defroster. This means, the thing is important and unfortunately quite expen….well, this is a Mercedes, so you know the word. Luckily, the module is fairly reliable, so it can help to just unplug and then re-plug the module’s cable.

Another focus should be the relay of the hydraulic pump, which is located at the right side of the trunk, hidden behind the side paneling. When the hardtop switch is pushed, the relay should make a clicking sound. If that does not happen, it needs to be checked with a multi-meter whether power is being sent to it. If no power is measured, either the hardtop switch or the wiring from the switch to the relay could be damaged. If there is power, but you cannot hear any clicking sound, the best thing to do is replace the (inexpensive) relay. And even if the relay is clicking, small internal parts could have worn out over the years, so that insufficient power is sent to the hydraulic unit to operate the hardtop. Replacing the relay is also in this case a good idea and might solve the problem

As mentioned earlier, the pump itself is fairly robust, but this does not mean it will not or cannot fail. Too low oil levels due to a leak can stress the pump. Or small debris particles from broken hydraulic cylinder seals within the fluid can ruin either the pump or the attached valve block. The other one is used for measuring the pressure inside. The word pressure means that there can be a bit of oil coming out the fill hole, once you try to open it, so a towel is advisable to cover the place a bit during the opening process. The pump has a min/max marker at the rear end of the reservoir.

The vario-roof control unit

The hydraulic pump (A7/5) with:

Y55/1: Hydraulic valve block

A7/5k1: Pump relay

A7/5m1 Hydraulic motor

Cleaning and greasing the hinges can be of help too, if the operation of the hardtop is slow. A regular lubing of all pivot points will improve the top’s operation. A possible reason for the top not to open or close completely can be a loose or hanging flap under the trunk lid. There are two of them and they are located close to the passenger compartment. Daimler-Benz offers a repair-kit for the flap problem.

The picture below should only serve as reference on how to use the kit and tighten the flaps, because this is a job better left to an experienced mechanic, especially as after the 2016 MOPF these flaps work electrically. If you still want to do it, it is best to ask the vendor for instructions. As a novice, you should be prepared to spend the better part of three to four hours to fix the flap issue.

These are just some of the ways to find or even possibly remedy problems with the vario-roof. Hopefully, for the wallet of the R231 owner, a possible malfunctioning can be associated with one of the cheaper to solve issues. Because it gets progressively more expensive, when the wiring or hydraulic cylinders are at fault. While switches, relays and cable connections can be replaced fairly inexpensively, a new hydraulic cylinder is more expensive, if it cannot be repaired. And there are eight of them!

Which R231 version to choose

In the ideal world, where money is no object and the sky always seems to be blue, the SL65 AMG has to be the ideal R231 to own and enjoy. It is a brutally powerful, almost addictive drug and the effortless way it can show its teeth has to be experienced to be fully appreciated. For the cognoscenti it is the ultimate gentleman’s express that will satisfy the demands of even the most power-hungry driver.

Yes, the SL63 can do all of this too, but when we talk this kind of car and money, it just lacks one important thing: the V12 engine. And wasn’t there always this saying that one of the few things a man owes to himself or he has to do at least once in his life was next to planting a tree the driving of a 12-cylinder car?

Unfortunately, this ideal world rarely exists, so the V12 is the car that most people do not dare to touch. The SL65 has depreciated percentagewise much more than its 8-cylinder siblings. Actually, its sales were at the end so low that Mercedes-Benz decided in 2018 to pull the plug on it. If you are a bit patient and wait a few more years, it will even sell at a level at which an SL500/550 can be bought. Which brings us to the car that everybody seems to want.

The SL500 is for the average driver not only brutally fast, it also comes with that deep growl that people like so much on a V8. Of course, the SL63 can do this even better, but for most of us, who want to drive a V8, the non-AMG car will definitely do. It is not only more comfortable, equally refined, comes with the same interior, and costs considerably less in insurance fees and maintenance, if we leave the fuel consumption aside. It is precisely this combination of immediate, almost casual power delivery even from the lowest engine speeds, combined with the wonderful sound of a V8, that makes the SL500 almost irresistible.

So, this is it then, the V8 is the way to go? No, not so fast. Because there is the V6 SL400/450. And many V8 nerds, the author included, who insisted that only a V8 will do, came away with a different opinion, after having driven the smaller sibling. This new biturbo V-6 might be down on displacement from its 3.5-liter predecessor, but it makes up for it with power — 26 extra horses and 81 extra pound-feet. Mercedes says 0 to 100 km/h time will drop 0.6 seconds, doing the deed in 5.2 seconds on its way to its 250 km/h governed top speed.

It’s a beautiful engine with masses of mid-range torque, decent response and a lovely soulful howl under heavy load, its bassy idle swelling into strong baritone howl. The note is not progressive; it gets louder, but does not have so much depth as the V8. Nevertheless, it is a sweet tune and not overbearing, punctuated with the occasional pop and subtle burble on throttle lift.

The SL400 is some 60 kg lighter, nimbler and offers a slightly more comfortable ride quality. Naturally it lacks the rollercoaster acceleration of the bigger boosted V8s, but is more than fast enough for any road situation. The V6 can feel a little lethargic in Eco mode, but in Sport mode it does exactly what it is supposed to. It accelerates hard, feeling lithe and not anywhere near its 1,730 kg. There is even a deliberate cackle on lift-off in Sport mode, which is nice but could be even more pronounced for the author.

We have not talked about prices yet, although if we talk about keeping the car for a couple of years, if not longer, the price factor should not be the main deciding factor. But of course, it will play a role too for many people, who want to buy such a car second hand. Let us have a look at cars built after the 2016 MOPF, because they come with the desirable 9G-tronic transmission. In Continental Europe an SL400 from 2017 with a decent list of extras (Magic Sky, Harman Kardon, Airscarf, etc) will cost you with around 50,000 km on the clock between €68,000 and €75,000 in summer 2022. An equally equipped SL500 with similar mileage will cost you between €73,000 and €86,000.

In the UK, an SL400 from 2017 with around 35,000 miles on the clock, costs between £34,000 and £38,000. A similar SL500, costs between £36,000 and £43,000.

The situation in the US looks as follows: a 2017 SL450 will cost between $57,00 and $64,000. The SL550 counterpart between $73,000 and $81,000. It is interesting that in all three markets there are more V6 cars on offer than V8 cars, which shows that for the majority of buyers the smaller engine plus the big difference in price for the new car was a convincing enough argument to go for the SL400/450.

So, where are we now? Well, if your automotive palette prioritizes performance over panache and you are willing to fork out an additional $10,000, go for the V8. But for those of us, who are in less of a hurry, and for whom motoring should be sumptuous rather than speedy, do yourself a favor and try the V6 for size. The author is sure, you will love it

Technical specifications

Special interior of a Brabus SL800

Technical data:

Technical data:

Technical data

In Europe quite a few SL350s came without AMG style body

Power and torque curves

Production data

Usually, you will find here in this author’s books detailed production data for each model per year. And for the last couple of years, MB has always given the author the data that he needed for his books. Not so for the SL R231, unfortunately, because the press department of Mercedes-Benz informed the author via the classic archive department that they refuse to give the author such data for this book. When the author asked for the reason, he did not receive an answer. So, the figures you find below are sourced from the internet. The figures for Europe include the UK. From looking at various sales sites in Europe, the UK and North America over the last couple of years, the author estimates that the model split looks as follows:

55% V6, 30% V8 and 15% AMG models.

* Rest of the world figures are estimated at 10% of total US/Europe sales

** As the ROW figures are estimates, also the total figures have to be estimates

How much the situation for cars like the SL has changed over the past decades can be seen from the following graph. In fairness to the R231 one has to add that the design was not regarded as the most striking and that the car suffered from internal competition. To give you one example, in 2019 Mercedes sold in Germany 271 SL, 462 AMG GT Cabrios, 276 S-Class Cabrios and 3,556 E-Class Cabrios. As the SL models had different lengths of production, only the last ten years are shown below. But the total figure shows the total production of the model.

Another interesting graph shows, how the R231 faired against its competition. Unfortunately, the author could only find such data for the US:

Exterior color options

The first chart shows the colors that were available for the R231 owner in 2013. Diamond While Metallic and Shadow Grey Metallic were design colors. Unlike with most other Mercedes cars, the color options did not change much over the years, as the second chart from 2019 shows. Metallic paints could be chosen at no additional cost. The matte color, Shadow Grey Metallic and Diamond White metallic both carried additional charges. Dolomite Brown was not available until the 3rd quarter of 2013.

An SL63 in polar white. Brilliant blue metallic (below), as on this SL500, is another nice color

Interior color options

The SL350 came in Europe standard with a black leather-fabric upholstery. At least that is what the 2012 brochure said. The author has yet to see an SL that came equipped like this. All other R231 models came standard with leather interior.

As one can see, there were basically five different leather designs available. Nappa, Exclusive nappa (not shown here) had the same design. The SL63 nappa design was different to the two non-AMG models. The diamond pattern (right picture) was exclusive to the SL65, but could also be seen on some special edition models of the SL63. Designo leather had a different design again (see next page)

While we are discussing the various leather options, let us have a closer look at them. The differences between standard leather, nappa, Exclusive nappa or Designo nappa leather was mainly in the quality of the leather material used. Nappa leather feels more subtle and softer, with a much finer grain than standard leather.

Designo leather is again a notch up over nappa leather. This standard leather covered the seats, headrests and the doors’ armrest. Everything else was covered by MB-Tex (a less offending word for plastic), MB-Tex came for example on the dashboard with special stitching and looked very close to the real thing. A nappa leather equipment was in Europe a €800 extra over standard leather. It also covered only the seats, center console and door armrests.

Only if you opted for the Exclusive (in some markets called Premium) nappa version for an additional €2,400 you got more of the passenger compartment covered in leather. Exclusive nappa was not better in quality than its nappa alternative. This price included also the Dinamica roof lining, which was otherwise a €1,530 option.

Designo nappa leather, a €5,450 option (SL63: €4,300, SL65: €3,800) was again the same leather quality as nappa, it only covered even more parts of the interior in leather. Plus, it came in colors, that were otherwise not available. It also had a different Designo-unique stitching.

Designo leather had its own unique design

Seat colors that were available more or less throughout the R231 production time. It could vary though from market to market

Interior trim options

There were various interior trim options available. Aluminum, Burl Walnut and Black Ash were the standard trim choices, although also Brown Poplar Wood was popular and available at no additional charge. These were the choices available:

Wheel options

There was a fair amount of wheel options available for the R231, as seen from this 2013 UK brochure:

What a difference in appearance to the 2017 SL63 below. The standard 17-inch alloys for the SL350 and SL400 had a rather awkward design and were not very popular. They were replaced in 2015 with better looking 18-inch ones. 17-inch tires were never used on cars destined for North America. By the way, if you drive a car without ABC and feel the ride to be too uncomfortable, go with smaller diameter (18-inch) wheels and non-run flat tires. “All Season” type of tires will generally have a sidewall slightly less stiff than that of a, let us say “Performance” summer tire, so they will offer a more comfortable ride

Outlook to the SL R232

Over the past fifteen years, Mercedes-Benz has gone to great lengths to turn the legendary SL into a sleeper car. The R231 series was less of an innovator than its predecessors and a shadow of its former self in terms of design, especially from the outside. Since then, sales figures have been plodding along without any great amplitudes, and the average age of drivers was probably well over 60. The pale appearance improved after the model update, but the S-Class Cabriolet and AMG GT Roadster made the topless veteran in the broad Mercedes portfolio more dispensable than ever. This was to finally come to an end, because with its successor, Mercedes and AMG aim to build on the sun worshipper's old successes, starting from fall 2021. This book is about the SL R231, but the author believes that it does not hurt at the end of this book to have a short look at what is to come after the R231.

The shape of the R232 was to be crisper, more elegant and sportier. Years ago, it would have been a good idea to turn the then newly created AMG GT / GT Roadster into the SL of the modern era - as was once the case in the 1950s: first closed and then open. But the decisions were delayed again and again, AMG was to be strengthened and so the SL fell from then on unloved between two stools, so to speak. Daimler CEO Ola Källenius announced a few months ago that Mercedes wants to become a luxury brand more than ever in the coming years. For this the company is currently streamlining its model range significantly, and the open-top versions are suffering more than ever.

When comparing this SL63 with the one at the end of the previous chapter, it becomes obvious that an extended wheelbase in conjunction with a much shorter frontal overhang benefits the overall looks greatly

The S-Class derived taillights look very good on this “Patagonia Red Bright” (993) SL63

The cabriolet versions of the C- and E-Class, which are positioned all too close to each other, are taking increasingly fewer prospective buyers away from each other. So the author guesses that only the open E-Class will survive. Those who want a more upscale, sportier look in the future will have to take the R232 SL. Those who want uncompromising sportiness and a two-seater will take the new AMG GT Coupe, which is most likely to be positioned even more sportily in the direction of McLaren and Ferrari.

But coming back to the SL, its new home is no longer Mercedes-Benz, but AMG. Production volume over the last couple of years was so low (only a total of 271 units were sold in Germany in 2019, 245 in 2020) that the development of a successor was shifted to AMG in Affalterbach. From an image point of view, Mercedes-Benz could not afford to cancel the SL, so the newly developed AMG aluminum architecture, which will also be used for the AMG GT Coupe, can ensure the survival of the iconic SL name. This means that customers, who buy an R232 will not get the car without the AMG logo. This is not anymore a Mercedes SL, this is an AMG SL, with all its consequences.

For the Affalterbach-based AMG company it is of great importance that the new SL has no components in common not only with its predecessor but also with the AMG GT Roadster. AMG combines an aluminum spaceframe and a self-supporting structure to create a new roadster architecture consisting of another material mix of steel, magnesium and fiber composites. In terms of torsional rigidity, the new SL is thus said to outperform its predecessor by 18 percent. Compared with the AMG GT Roadster, transverse stiffness is 50 percent higher and longitudinal stiffness 40 percent higher.

The AMG SL, which has grown by seven centimeters to an overall length of 4.70 meters, wants to be seen as a 2+2-seater, although with the rear seats more worthy of a sports bag than an adult human being, it is actually a 2+0-seater. While the second row can be used to increase the load volume of the trunk, these new seats automatically make the trunk volume shrink to 213 liters with the top down, or 240 with it up. The R231 could swallow a much more useful 485 liters with the roof up. Why the rear seats then? Marketing says that consumer surveys among R230 and R231 owners suggested they wanted more space behind the front seats. Talking about the R231, the new soft top saves a little more than 20 kilograms. Yet, depending on the version, the R232 weighs 1,950 or 1,970 kilograms when ready to hit the road. That is over 150 kilos more than before. Why was the vario top abandoned? Design chief Gordon Wagener said: "If you start with a retractable hard top again, you will get what you had in the R231, which is not appealing in my view."

Weight aside, AMG promises the R232 to be the sportiest SL roadster since the racing-derived 300SL from 1954. The car is offered as the SL55 and the SL63, both using a 4.0-liter twin-turbocharged V-8. For the first time, the SL’s engine will be powering all four wheels, as AMG’s 4Matic+ all-wheel drive is standard on both models. The R232 looks smoother and rounder, has a larger cabin, a shorter front and a stubbier tail. Both models roll on 20-x-9-inch front and 20-x-11.5-inch rear wheels, with 21s available as an option.

Starting May 2022, also the in-line two-liter four-cylinder SL43 became available. As a first in a production vehicle, it offers an electric exhaust gas turbocharger, which is a direct derivative of a development successfully used by the Mercedes-AMG F1 team for many years. This new form of turbocharging should guarantee spontaneous throttle response across the entire rev range, according to AMG.

The cabin features a digital instrument cluster and a large center touchscreen, but they are not merged under a single piece of glass as in some Mercedes models. Instead, the SL uses separate screens as in the S-class (Is it really appropriate for the SL?). In the roadster, the 11.9-inch portrait-oriented center display is adjustable in angle to be more easily seen with the top down. A problem will be the most upright position, which puts the screen closer to the driver. When he/she wants to look at it, the driver’s face has to turn way more to the right, which is dangerous, when driving! Of course, the infotainment runs the latest MBUX operating system including the "Hey, Mercedes" digital assistant, which might be safer than using the touchscreen, when the car is in motion

This interior of the red SL63 is called Manufaktur (previously: designo) Macchiato Beige/Grey

When driving the new SL, a big surprise is the turning circle. Because thanks to the new all-wheel steering the roughly five-meter-long SL turns almost like a hatchback. Even a C 63 might not spin around so easily.

Another improvement is the revised forward seating position, which is almost centered between the axles and allows better orientation - urgently needed, because the vehicle width is borderline for narrow roads. A result of the shorter front: V8s like the already familiar four-liter and inline four-cylinders fit in. The longer inline six cylinders that Mercedes has switched to, however, will not.

And thanks to miracles of modern science, the car also tries to deliver comfort on par with that of the non-AMG R231. Oh well… a luxury roadster in Comfort mode drives differently, and the point is clear: anyone, who liked his SL500/550 not only because of its speed potential, but also because of its comfortable ride and now buys the new SL should enjoy driving dynamics. For 50 years, the SL had become the comfortable and, depending on the engine, even sporty roadster for those, who could afford it. This was especially true of the R231 series. In the future, Mercedes-Benz will have to do without them.

Conclusion:

Chassis, seats, powertrain - everything follows one idea: sports car, back to the roots. The new SL does not only look fantastic, it also drives fantastic and offers top quality materials. Many people will love it, also the press is raving about it. No other SL after the Gullwing and its roadster derivative has ever followed this sports car mantra so closely. As convincing as it might be, the break with the SL’s traditional clientele is an obvious risk.

Prices in Euro for the new models are as follows:

SL43, 381 hp: €118,702

SL55 4Matic, 476 hp: €158,240

SL63 4Matic, 585 hp: €187,098

About the author

I grew up in the 1950s and 1960s in Northern Germany and my interest in anything automotive started early on visits to the Nürburgring with my father. I grew up with Mercedes cars in our family and my uncle, who had a small collection of pre-war cars, introduced me at the end of the 1960s to vintage cars. From the mid-1970s I started collecting vintage cars himself. Naturally my first such car was a Mercedes, a rather neglected prewar 170V Cabriolet B. Later additions were among others a 200D fintail, 250SE, 350SL, 300d Adenauer and a 280SE 3.5 Coupe.

Mercedes cars became a passion I have kept and further developed throughout the years with an interest now also in more modern Mercedes cars, here especially the S-class derived coupes and everything SL and SLK. My other weakness revolves around British cars, here especially Alvis and Jaguar.

In case you like to know more about my books or read my blog, please visit my website:

http://www.benz-books.com

I wanted to keep most of the administrative stuff out of my e-books, so you will find all info about my other books and e-books plus the acknowledgements etc. on my website.

Other books by the author

Printed books:

MB, The 1950s Volume 1: from the 170V to the 300Sc Roadster

MB, The 1950s Volume 2: from the 180 Ponton to the 300SL Roadster

MB, The 170 series: from the 1936 170V to the 170S Cabriolet

MB, The 1950s, The 300SL Coupe and Roadster

MB, The 1950s, The 190SL Coupe and Roadster

MB, The 1950s, The 300 Series: from the 300 Sedan to the 300Sc Cabriolet

MB, The 1950s, The Ponton Series: from the 180 Sedan to the 220SE Cabriolet

MB, The 1960s Volume 1: from the 190c to the 280SE 3.5 Cabriolet

MB, The 1960s Volume 2: from the 230SL and 600 to the 300SEL 6.3

MB, The 1960s, W110 Sedan: from the 190Dc to the 230

MB, The 1960s: W111: from the 220b, Sb, SEb and SEC to the 230S

MB, The 1960s, W111/112C: from the 220SE Coupe to the 280SE 3.5 Cabriolet

MB, The 1960s, W112: from the 300SE Sedan to the 300SE Cabriolet

MB, The 1960s, W113: from the 230SL to the 280SL

MB, The 1960s, W108/109 six-cylinder Sedan

MB, The 1960s, W108/109 V8 Sedan

MB, The 1960s, W100: from the 600 to the 600 Pullman Landaulet

MB, The 1970s: W116: From the 280S to the 450SEL 6.9 Sedan

MB, The early SL cars: from the 300SL Gullwing to the 280SL Pagoda

MB, The modern SL cars: from the 350SL R107 to the SL65 AMG R231

MB, The modern SL: The R107 from 1971 – 1989

MB, The modern SL, The R129 from 1989 – 2001

MB, The modern SL: The R230 from 2001 – 2011

MB, The modern SL: The R231 from 2012 – 2020

MB, The SLK R170 from 1996 – 2004

MB, The SLK R171 from 2004 – 2011

MB, The SLK R172 from 2011 – 2020

E-books:

MB, The 170V and 170S (W136) Sedan, OTP and Cabriolets from 1936 – 1955

MB, The 1950s: The 220 (W187) Sedan, Cabriolets and OTP from 1951 – 1955

MB, The 1950s: The 300 (W186, W189, 1951 – 1962) and 300S, Sc (W188, 1951 – 1958)

MB, The 1950s: The 180, 190 (W120, W121) Ponton Sedan from 1953 – 1962

MB, The 1950s: The 219, 220a, S, SE (W 105, W180, W128) Ponton from 1954 – 1960

MB, The 1950s: The 300SL (W198) Coupe and Roadster from 1954 – 1963

MB, The 1950s: The 190SL (W121) from 1955 – 1963 and Max Hoffman

MB, The 1960s: The 220b, Sb, SEb and SEC, 230S (W111) from 1959 – 1968

MB, The 1960s: The 190c, 200, 230 (W110) Sedan from 1961 – 1968

MB, The 1960s: The 220, 250, 280, 300SE (W111, W112) Coupe/Cabriolet from 1961 – 1971

MB, The 1960s: The 300SE, SEC (W112), 1961 – 1967

MB, The 1960s: The 230, 250, 280SL (W113) Pagoda from 1963 – 1971

MB, The 1960s: The 600 (W100), 1963 – 1981

MB, The 1960s: The 250, 280, 300 (W108, W109) six-cylinder Sedan from 1965 – 1972

MB, The 1960s: The 280, 300 (W108, W109) V8 Sedan from 1967 – 1972

MB, The 1970s: The 280, 300, 350, 450, 6.9 (W116) Sedan from 1972 – 1980

MB, The SLK R170 from 1996 – 2004

MB, The SLK R171 from 2004 – 2011

MB, The SLK R172 from 2011 – 2020

MB, The modern SL: The R107 from 1971 – 1989

MB, The modern SL: The R129 from 1989 – 2001

MB, The modern SL: The R230 from 2001 – 2011

Free book offer

I hope that you have enjoyed reading a bit about the SL R231. If you are interested in a printed version, here is the link to the book in hard and soft cover. This is the US Amazon link. If you live outside the US, you will find it under the same title at your local Amazon website.

When you turn this page, Kindle/Amazon will give you the opportunity to rate this book. Your comments will then appear in the review list of my books. If you believe this book is worth sharing, would you be so kind and take a few seconds to let other Mercedes enthusiasts know about it. Maybe they would be grateful. As a small volume author, I will be for sure, as it will help me to gain a bit of recognition. If you will find the time to write a short review, I would like to offer you a small gift. You can choose one of my 22 Mercedes e-books and I will send it to your e-mail address free. Of course, I will never spam you.

Please let me know via e-mail, where you have written your review. Here is my e-mail address: bernd@benz-books.com

Alles Gute,

Bernd