The Mercedes-Benz SLR McLaren was first manufactured in 2003 with the Mercedes factories last unit, in a roadster version, rolling off the assembly line in March 2008. The SLR McLaren design was inspired by and modeled after the Mercedes W 196 race car from the mid 1950’s. It features a brake-by-wire Sensotronic system and has carbon-ceramic discs for fade resistant stopping power up to 1,200 degrees Celsius (2,200 degrees F). The front 370 mm (15 inch) discs have internal venting with eight piston calipers while the rear 360 mm (14 inch) discs use four piston calipers. Both front and rear discs have a system in place that automatically wipes rotor faces to keep them dry during wet weather. When the disc brakes are applied on the McLaren at high speed, the rear spoiler adjusts to 65 degrees to enhance stopping ability. “Active aerodynamics” is the buzz-word and this spoiler will, without driver prompting, rise to 10 degrees (15 degrees in the 722 model) at a preset speed while accelerating to increase down force and then automatically readjusts on brake application.
Under the hood the SLR sports a hand built 331.9 cu in (5.44 L) SOHC V8 engine with a compression ratio of 8.8:1 and will generate 617 hp (460 kW; 626 PS) at 6,500 rpm and maximum torque of 580 lb-ft (780 N-m) from 3,250 to 5,000 rpm. The front mounted engine cylinders are at an angle of 90 degrees and the heads contain three valves for each cylinder. The fuel is supplied by a Lysholm-type twin screwed supercharger which rotates at 23,000 rpm producing 0.9 bar (13 psi) of boost then the compressed air cooling is supplied by two inter-coolers The engine is bolted to an AMG SPEEDSHIFT R five speed automatic which can optionally be used in three manual modes as well.
The weight in the building of the SLR was a major consideration with many body parts made from a carbon fiber reinforced plastic. The car has a curb weight of 1,750 kg (3,858 lbs). The best times were recorded by “Road and Track” but they commented that times in the trials could be faster in cooler weather. They recorded the SLR doing 0-60 (97 km/h) in 3.4 seconds and a standing quarter in 11.2 seconds achieving a speed of 130 mph (210 km/h). The acceleration from 30 to 50 mph was 1.7 seconds and from 50 to 70 mph was 2.4 seconds which is the quickest time the magazine has ever recorded for a production automobile.
The SLR 722 S roadster version was produced as a limited edition of 150 units in 2009.and can reach 100 km/h (62 mph) in 3.6 seconds with a top speed of 334 km/m (208 mph).
This roadster variation was in showrooms by September 2007 but is heavier than the coupe although it still can achieve a top speed of 208 mph (334 km/h) and will do o to 100 km/h (62 mph) in 3.8 seconds. According to an official Mercedes document passenger and driver can hold a conversation with the top down while travelling up to 200 km/h (120 mph).
Ray Mallock LTD., with Mercedes-Benz permission, reworked a 722S Mclaren which resulted in a highly tuned engine developing 670 hp (500 kW; 680 PS). This version of the SLR 722 is called the 722 GT and sports slightly modified fenders to hold the racing slicks he also added a rear wing with defuser. The interior has been stripped of all but necessary equipment and a roll cage has been added.This stripped down model has had a binnacle added and doors without inner panels replaced, with both revisions made of carbon fiber, further reducing the cars weight to 398 kg/h (877 lbs). RENNtech builds and markets this version now and it is an exclusively offered to the North American market as the “21 SLR Mclaren 722 GT.”