history SLR mclaren


The Mercedes-Benz SLR McLaren was inspired by the Mercedes-Benz 300 SLR of 1955, based on the W196 F1 car, yet named after the road-going 300SL Gullwing. On 4 April 2008, Mercedes announced they would cease production of the SLR. The last of the coupes rolled off the production line at the end of 2007 and the roadster version was discontinued in early 2009.

The SLR features Sensotronic, a type of brake-by-wire system. The brake discs are carbon-ceramic (in the front only) 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.

Rear view of the SLR McLaren Roadster

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%.

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 spoiler raises.

Engine

The SLR McLaren sports a hand-built 5.4-litre, supercharged V8 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

A Mercedes-Benz SLR in motion

Mercedes-Benz SLR McLaren 722
Mercedes-Benz SLR McLaren 722 at Goodwood Festival of Speed 2009

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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 1,768 kg (3,898 lb). The following tests have proven that the SLR can achieve a 0-100 km/h (62 mph) in times less than the claimed 3.7 seconds and reach a top speed of 334 km/h (208 mph).

Car and Driver achieved a 0-60 mph (100 km/h) time of 3.6 seconds, and a quarter-mile time of 11.6 seconds at 125 mph (201 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 3.6 seconds in April 2006. Car and Driver achieved 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 0.97 g on the skidpad.January 2005

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 10.3 seconds and 0-300 km/h (190 mph) in 30.4 seconds.[citation needed] Their 400 metre and kilometre times were 11.4 seconds at 128 mph (206 km/h) and 20.6 seconds at 270 km/h (170 mph) respectively. They also reached its claimed topspeed 365 km/h (227 mph).

Comparison

Despite its near 2-ton weight, the fuel economy is generally better than the lighter Lamborghini Murciélago, and even its lighter, less expensive, less powerful sibling, Gallardo.[6] Still, on the Episode 2 from Season 13 of BBC car show Top Gear the Lamborghini Murciélago LP670-4 SV performed as well as the SLR McLaren 722 Edition during a race special in Abu Dhabi. Also, the same show put the SLR and the Porsche Carrera GT on its track, and after multiple attempts, the Porsche beat the SLR-McLaren by just over a second (1:19.8 vs. 1:20.9). However, on a separate race around their short track, the SLR was fractionally quicker than the Carrera GT. In a straight line, the SLR is quicker after around 150 miles per hour.

Variants

722 Edition

The Mercedes-Benz 722 Edition features some upgraded styling.

SLR McLaren 722 Roadster Variant.

A new version was introduced in 2006 called the Mercedes-Benz SLR McLaren 722 Edition. The “722″ refers to the victory by Stirling Moss and his co-driver Denis Jenkinson in a Mercedes-Benz 300 SLR with the starting number 722 (indicating a start time of 7:22 a.m.) at the Mille Miglia in 1955.

The “722 Edition” includes an engine rated 650 PS (480 kW; 640 hp)@6500rpm and 820 N·m (600 lb·ft)@4000rpm, with top speed of 338 km/h (210 mph) (3 km/h (1.9 mph)[citation needed] faster than the standard SLR). 19-inch light-alloy wheels were used to reduce unsprung weight, while modifications were also made to the suspension, with a stiffer damper setup and 10 mm (0.39 in) lower ride height introduced for improved handling. Larger 390 mm (15 in) diameter front brakes and a revised front air dam and rear diffuser were fitted.

Exterior changes, other than the larger 19-inch (480 mm) black light-alloy wheels, include red “722″ badging, harking back to the original 722 racer, and slightly different taillights and headlamps.

The SLR 722 can go from 0 to 100 km/h (62 mph) in 3.6 seconds, 200 km/h (120 mph) in 10.2 seconds and 300 km/h (190 mph) in 29.6 seconds and can reach a top speed of 338 km/h (210 mph).

Roadster

2008 Mercedes-Benz SLR McLaren roadster

A roadster version of the SLR went on sale in September 2007 for £350,000 ($711,065 U.S.). It uses the same supercharged V8 AMG power plant as its coupé siblings, developing 626 PS (460 kW; 617 hp), to propel it to a top speed of 332 km/h (206 mph) and enable 0-100 km/h (62 mph) acceleration time of 3.8 seconds.

However, as a convertible the roadster was burdened with extra weight and this affected performance and handling. The Roadster’s roof is made from a “newly developed material” and does not take the form of a folding metal arrangement, as is now common on many modern cars. Following a manual unlatching, it takes a mere ten seconds to fold away electrically. According to an official document from Mercedes, the cabin of the roadster is capable of allowing conversation between driver and passenger up to a speed of 200 km/h (120 mph) with the roof retracted. This roadster is aimed to compete against other sports cars such as the Pagani Zonda F Roadster.

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