Mercedes-Benz SLR McLaren

Technical highlights:

Brakes:

The SLR features Sensotronic, a type of brake-by-wire system. The brake discs are carbon-ceramic and provide better stopping power and fade resistance than steel discs when operating under ideal working temperature. Mercedes-Benz claims these discs are fade resistant to 1,200 °C (2,200 °F). The front discs are internally vented and 370 mm (15 in) in diameter. 8 piston calipers are used. Rear discs are 360 mm (14 in) in diameter with 4 piston calipers. During wet conditions the calipers automatically skim the surface of the discs to keep them dry.

To improve braking performance there is an automatic air brake, when engaged the rear elevation angle of the rear spoiler is set to 65 degrees. The additional rear downforce in addition to the markedly increased aerodynamic drag increases peak deceleration ~90%.

The brakes have been strongly criticized by such review sources as Top Gear due to lacking modulation and having an on-off operation. This is due to road cars not regularly reaching normal operating temperature for ceramic discs in stop-go traffic conditions.

Aerodynamics:

The SLR features active aerodynamics; there is a spoiler mounted on the rear integral air brake flap. The spoiler increases downforce depending on its angle of elevation (angle of attack). At speeds above 95 km/h (59 mph) the spoiler/brake automatically raises to 10 degrees (15 in 722 edition), when demanded via the driver's switch, the elevation can be increased to 30 degrees (35 in 722 version) for increased rear downforce, at the cost of increased steady state drag, also when the driver applies the brakes the spoiler raises.

Engine:

The SLR sports a 232 kg (510 lb) hand-built 5,439 cc (5.439 L; 331.9 cu in), supercharged, all-aluminium, SOHC V8 engine. The cylinders are angled at 90 degrees with three valves per cylinder and lubricated via a dry sump system. The compression ratio is 8.8:1 and the bore and stroke is 97 millimetre (3.82 in) and 92 millimeters (3.62 in), respectively. The Lysholm-type twin-screw supercharger rotates at 23000 revolutions per minute and produces 0.9 bar (13 psi) of boost. The compressed air is then cooled via two intercoolers. The engine generates a maximum power of 626 PS (460 kW; 617 hp)@6500rpm and maximum torque of 780 N·m (580 lb·ft)@3250-5000rpm.

Unlike most of its contemporaries, its engine is front-mid mounted. McLaren took the original concept car designed by Mercedes and moved the engine 1 metre (39.4 in) behind the front bumper, and around 50 centimetres (19.7 in) behind the front axle. They also optimized the design of the center firewall.

Transmission:

The SLR uses AMG SPEEDSHIFT R 5-speed automatic transmission with 3 manual modes. For durability Mercedes selected a 5-speed transmission rather than their 7-speed gearbox which was more complex and used more parts.

Performance:

The car uses carbon fibre for its entire body construction in an attempt to keep the weight low. Despite CFRP materials the total curb weight is 1,750 kg (3,858 lb).

Car and Driver achieved a 0-60 mph (100 km/h) time of 3.4 seconds, and a quarter-mile time of 11.2 seconds at 130 mph (209 km/h) C&D suggests the times may be even lower if temperatures were lower. Motor Trend tested the SLR and achieved a 0-60 mph time of 3.3 seconds in April 2006. Car and Driverachieved top gear acceleration 30-50 mph and 50-70 mph times of 1.7 and 2.4 seconds, which are the fastest ever recorded by the magazine in a production car. The SLR also pulled 1.13 g on the skidpad.

Road and Track tested the car in their July 2005 Road Test and reached 60 mph (97 km/h) from a standstill in 3.5 seconds. The 0 - 100 mph (160 km/h) sprint was achieved in 7.5 seconds and a quarter mile run was completed in 11.5 seconds at 126 mph (203 km/h).

In June 2004 the SLR was tested at Nardo and performed the 0-100 km/h (62 mph) exercise in 3.8 seconds, 0-200 km/h (124 mph) in 10.7 seconds and 0-300 km/h (190 mph) in 30.6 seconds.