Automotive fascination combined with spectacular racing car design – the new Mercedes-Benz SLS AMG GT3. This racing version of the gullwing model was designed as a customer sports car for competing in race series according to the near-series FIA GT3 rulebook. Outstanding driving dynamics are ensured by uncompromising lightweight construction and specific modifications to the suspension, brakes and aerodynamics.
The purist design of the SLS AMG, with its long bonnet, flat greenhouse positioned well to the rear and short rear end, is enhanced even further by the GT3 variant. The modifications to the body give the gullwing an even more spectacular appearance. The aim is a further improvement in aerodynamic performance.
At the front the GT3 racing car has a new front apron with larger air intakes: the wide aperture below the characteristic radiator grille with a large Mercedes star and a wing-shaped transverse fin supplies the engine oil cooler and brake discs with cooling air. The two air intakes below the vertically arranged bi-xenon headlamps have the same function. Downforce at the front axle is provided by four externally mounted “flics” and the carbon-fibre front splitter: this blends into the smooth underbody cladding which ends with the rear diffuser.
The bonnet has a central aperture to dissipate the engine heat. The hot air is vented in the wheel arches from side vents in the front wings. Particularly lightweight polycarbonate glazing is used all-round.
The front and rear wheel arches are flared to make space for the large racing tyres. With a width of 1990 millimetres, the body of the GT3 is a good 50 millimetres wider than that of the standard SLS AMG. The new side skirts have apertures for cooling the rear brakes. The smooth underbody is visible at the lower edges of the side skirts. The standardised filler pipe for the fast-refuel system is accommodated in the B-pillar. The 120-litre fuel tank is centrally located behind the driver.
Wide rear apron of carbon-fibre
Viewed from the rear, the SLS AMG GT3 impresses with its sheer width. The boot lid is surmounted by a wide carbon-fibre rear aerofoil, which has multiple adjustments and allows a perfect setup for the type of racetrack concerned. The new rear apron features two apertures designed to vent the rear wheel arches. The carbon-fibre rear diffuser is another eye-catching feature: as an extension to the smooth underbody, it gradually rises in the rear axle area and generates a downforce thanks to its shape. The overall aerodynamic concept of the SLS AMG GT3 was refined and finalised in extensive wind tunnel and racetrack tests. All the resulting measures ensure a high level of aerodynamic efficiency, and also guarantee effective cooling of thermally highly stressed components.
The rain light prescribed by the rulebook is integrated into the boot lid – it must remain permanently switched on if the weather conditions are poor.
Near-series AMG 6.3-litre V8 engine
As prescribed by the FIA GT3 rules, the AMG 6.3-litre V8 engine is practically identical to that in the standard model. Thanks to its lower weight, the GT3 will considerably better the already outstanding acceleration of the standard model – 3.8 seconds from zero to 100 km/h; depending on the final drive ratio, the top speed will exceed 300 km/h. Typical of an AMG: the thrilling and characteristic eight-cylinder sound.
The peak output of the AMG 6.3-litre V8 front-mid-engine with dry-sump lubrication is determined by the FIA according to the “Balance of Performance”. This is to ensure equal chances for all the participating racing cars. Classification, which also determines the kerb weight of the vehicle and other factors, will take place in spring 2011.
The AMG 6.3-litre V8 engine also has a dry sump lubrication system in the racing model. Using vacuum and pressure pumps, as well as an external oil tank, makes it possible to dispense with a conventional sump. This technology ensures reliable engine lubrication even under the high lateral acceleration forces encountered on the racetrack. Dry sump lubrication also allows a low installed position for the V8 engine – one of the key technological highlights of the SLS AMG. Installing the eight-cylinder as low as possible, as a front-mid-engine behind the front axle, and combining it with a transmission located at the rear axle, leads to a favourable weight distribution. The transaxle arrangement also optimises handling and traction.
Six-speed racing transmission with sequential gear-changes
Unlike in the standard model, power in the SLS AMG GT3 is transferred by a six-speed racing transmission with sequential gear-changes. Thanks to its compact construction, this race-tested transmission has advantages in terms of packaging – after all, the GT3 version has a smaller ground clearance than the standard model. The driver shifts the gears using two shift paddles on the steering wheel. The transmission is mounted directly on the rear axle, and connected to the V8 engine via a flexurally and torsionally rigid torque tube. This has decisive advantages with respect to handling dynamics, as this sophisticated solution enables the entire powertrain to be configured with far less free play. In conjunction with the traction control sysem, a multi-disc locking differential integrated into the transmission ensures outstanding acceleration. A drive shaft rotates at the engine speed within this torque tube. As in the standard model, and also the Mercedes-Benz C-Class DTM racing cars, the shaft is made from carbon-fibre (CFRP).
Double wishbone axles of forged aluminium
The vehicle concept of the SLS AMG is predestined for top-class racetrack performance, with a long wheelbase, a low centre of gravity and a wide track. Its strengths include precise over/understeer characteristics, first-class agility, low inertia during fast changes of direction and high physical limits when cornering.
Very few modifications were required for perfect racetrack performance: the lowered, lightweight aluminium suspension with double wishbones all-round has the ideal kinematics. Multiple adjustments allow the best possible adaptation to the relevant racetrack characteristics and prevailing weather conditions. Not only the spring and damper setups, but also the track width and camber, the suspension height and the stabilisers at the front and rear axles can be adjusted.
Steel motorsports braking system with racing ABS
The rack-and-pinion steering with a more direct ratio and servo assistance supports the agile handling. Behind the 18-inch AMG light-alloy wheels with central locking, effective, fade-resistant deceleration is ensured by a steel motorsports braking system. The SLS AMG GT3 has precisely calculated cooling ducts: apertures in the front apron and ahead of the rear wheels supply the brake discs with a cooling airflow. All four brake discs are ventilated, grooved and perforated. Six-piston fixed callipers at the front and four-piston fixed callipers at the rear provide very generous brake lining surfaces. An anti-lock braking system specially configured for the racetrack is standard equipment.
The size 12 x 18-inch (front) and 13 x 18-inch (rear) AMG light-alloy wheels with central locking are shod with racing tyres. Depending on the conditions, untreaded slicks, intermediates or rain tyres are used. The classic multi-spoke design assists ventilation of the braking system. Rapid pitstops and wheel-changes are assured by the pneumatic jacking system integrated into the underbody: four pneumatic jacks lift the GT3 racing car by around 190 millimetres to allow very rapid tyre-changes by the pit crew.
Functional racing car atmosphere, exemplary safety level
The interior of the SLS AMG GT3 has a distinctively functional racing atmosphere. As in the standard gullwing model, the powerfully arching wing section of the dashboard gives an impression of width. Strikingly integrated into the dashboard, the air vents galvanised in “Silver Shadow” have adjustable, cruciform nozzles reminiscent of an aircraft’s jet engines.
In a set-up similar to that of the Mercedes-Benz DTM vehicles, the seat shell is located in a high-strength carbon-fibre (CFRP) safety cell. Thanks to its special form, the safety cell, which is bolted to the rollover cage and the aluminium spaceframe, offers far greater protection for the driver’s shoulders, hips and legs. The seat shell is individually foam-padded, features the HANS (Head and Neck Support) system, and is equipped with a six-point seat belt, thus maximising occupant safety. Additional safety is provided by the steel rollover cage, which also gives further reinforcement to the aluminium spaceframe. In conjunction with the 120-litre CFRP safety tank with inner bladder positioned on the rear axle, and the optimised fire extinguisher system, the SLS AMG GT3 provides an exemplary level of safety that is unmatched by any other current GT3 vehicle.
The central display is ideally positioned within the driver’s field of vision and provides all the relevant information such as track speed, engine rpm, operating temperatures, lap times and gear selection. The racing steering wheel with shift paddles for gear changes allows perfect control of the vehicle, and its quick-release mechanism makes access and egress much easier. The buttons on the steering wheel boss enable the driver to activate additional functions such as the two-way radio, headlamp flasher or drinking function. Additional controls are located on the centre console. Here the driver can start the AMG V8 engine and adjust the traction control, as well as engage reverse gear or – if the worst comes to the worst – activate the integrated fire extinguisher system. Brake balance adjustment is also possible.
Testing program with Bernd Schneider started in June 2010
Development of the new Mercedes-Benz SLS AMG GT3 is proceeding on schedule; the testing program began on the Lausitz Eurospeedway in June 2010. Bernd Schneider (46) – who has been a Mercedes-Benz works driver for many years and is also an AMG brand ambassador – and Thomas Jäger (33) were brought on board as test drivers. With five DTM titles, one ITC championship and one FIA GT championship to his name, Bernd Schneider is one of the most successful German racing drivers. Thomas Jäger is the reigning Porsche Carrera Cup (Germany) champion, and drove in the DTM for Mercedes-Benz between 2000 and 2003. This season he is lining up in the ADAC GT-Masters (Germany).
For Bernd Schneider, who will be doing the bulk of the test driving, developing a basic setup is a top priority.
“The SLS AMG has excellent genes for being successful in motor racing. Even on my first fast laps at the Lausitz Eurospeedway, it was obvious that the GT3 version of the gullwing model has just what it takes to be a hit on the racetrack. The combination of optimum weight distribution, a low centre of gravity, a powerful AMG V8 engine and efficient aerodynamics already indicates that the SLS AMG GT3 will be very competitive.”
First competitive action in the VLN race on the Nürburgring Nordschleife
As well as being tried out at the Lausitz Eurospeedway and the Sachsenring circuit, the SLS AMG GT3 is also being tested on the Nürburgring Nordschleife (North Loop) – under realistic racing conditions. On top of the pure testing and tuning drives, the gullwing model is also racing in the 2010 VLN endurance championship.
The extensive development and testing program focuses on various suspension settings, engine mappings, tyre mixes and aerodynamics configurations. In addition to this, the complete package has to prove its durability and serviceability. At the same time, the AMG 6.3-litre V8 engine and the six-speed racing transmission with sequential gearshift are being run on the test stations at HWA AG. Plus the entire vehicle is being tested on a driving-dynamics test station.
Teams can count on service and replacement parts
Mercedes-AMG and HWA will also be assisting the teams with service and replacement parts within Europe. The concept for the 2011 European motorsport season envisages offering comprehensive support in the three key championships and the major 24-hour races involving the SLS AMG GT3. A 24-hour replacement-part service and a technical hotline will be available for all other races and test drives.
Orders for the SLS AMG GT3 placed directly with Mercedes-AMG
Interested teams can order the Mercedes-Benz SLS AMG GT3 directly from Mercedes-AMG GmbH. The sales price is € 334,000 (net)/€ 397,460 (incl. 19% VAT). The vehicle is only available with left-hand drive. Deliveries commence in February 2011, following homologation by the FIA in accordance with the GT3 regulations. For interested customers, the AMG Driving Academy offers special SLS AMG GT3 driver training.