Mercedes-Benz SLR McLaren 722 GT: Race Car Modifications

Motoring Channel Staff - 31/October/2007

Stuttgart, Germany — Not unlike Ferrari's recently released FXX Evolution, Mercedes just launched it's own track-only race car for the well-heeled customer.

Entitled the Mercedes-Benz SLR McLaren 722 GT, it's been modified to the point where it didn't make sense to make it road legal. Yep, this is one is a purebred track car with a top speed of 315km/h due in part to its modified gearing and tuned 5.5-litre supercharged V8 powerplant.

Almost everything about the car has been changed, including its eligibility for road use. The aerodynamics have been improved, allowing the car to slice through the air without as much drag, it's lighter which makes it accelerate, turn, and brake with more urgency.

The SLR McLaren's engine was never in dire need of more power in the first instance, but the crew behind this upgrade (British motor racing specialists RML Group, aka Ray Mallock Ltd) have comprehensively altered the engine, redesigning more than 400 engine components.

"Compared to the series-production version, the SLR 722 GT has been uniquely and comprehensively re-engineered by RML, especially with respect to the suspension, braking system, aerodynamics, interior and exhaust system," boasts the press release.

The key modifications to the engine, which improve power by 15kW to 500kW (680hp) and add 10Nm for a total of 830Nm of torque, were the addition of a racing air filter, a wickedly loud racing exhaust system and increasing the supercharger pressure to 25 psi (1.75 bar) while strengthening the engine's internals to cope.

The engine's power is transferred to the rear wheels via a 5-speed automatic transmission with steering wheel shift paddles, which has been adapted by RML to racing conditions. The Mercedes-Benz SLR McLaren 722 GT also benefits from a mechanically locking differential with a locking effect of 70% under acceleration and 80% on the overrun. This ensures traction without loss of power. 

Just 21 of these dynamic two-seater race cars will be built, and with a kerb weight of 1390kg and peak power of 500 kilowatts, the zero to 100km/h dash is over in an explosive 3.3 seconds - three tenths quicker than the standard Mercedes-Benz SLR McLaren 722 model.

There's more than just a 'GT' badge added to the exterior as well. As the photos make clear, this is no ordinary sports car - it's a fully realised race car for the super rich CEO. The new body work includes the subtle new rear wing, a new look engine hood, and a motor sports front apron with front splitter. 

There's also extended wheel arches, stick-on side skirts, and the most impressive rear diffuser we've seen in months. According to the car maker, the aggressive body work additions are "obvious indicators of outstanding racetrack performance and extensive aerodynamic development work."

Getting the car's weight down from 1724kg to 1390kg is an incredible feat, and "numerous comfort features" were dispensed with to achieve the huge weight reduction.

With the new Mercedes-Benz SLR McLaren 722 GT "Fast lap times are guaranteed by the newly developed suspension," says the car maker. The wheels have been pushed wider at both the front and rear (hence the wide body kit) which is claimed to provide"improved kinematics and lateral dynamics". 

Other chassis upgrades, such as a modified anti-roll bar at the front axle, reduces roll when cornering and an adjustable wheel camber system allows drivers to fine tune their track setup. Fully adjustable shock absorbers with variable compression and rebound levels are part of the package, as are 18-inch wheels with central locks allow fast tyre-changes during a race, and can be used with a pneumatic jacking system.

The brakes have been beefed up, featuring "highly efficient, fade-resistant braking... provided by the new racing brakes complying with FIA GT regulations, which feature a modified cooling airflow and adjustable balance."

While the interior has been systematically stripped of all niceties, it does get a roll cage, a new look instrument panel complete with racing displays, plus a motor sports steering wheel and heavy duty bucket seats with six-point seat belts.

Expect to see more of British motor racing specialists RML Group on the future production models.

Related Links:
- Mercedes-Benz F 700 Concept (2007)
- Mercedes-Benz C 63 AMG Estate (2008)
- Mercedes-Benz C-Class Estate (2008)
- Mercedes-Benz New C-Class (2008)
- Mercedes-Benz C63 AMG (2008)
- Mercedes-Benz SLR McLaren Roadster (2007)
- Mercedes-Benz CL 65 AMG (2008)
- Mercedes-Benz CL-Class (2007)
- Mercedes-Benz Ocean Drive (concept)
- Mercedes-Benz GL-Class (2006)