Mercedes-Benz and its Formula One racing partner McLaren apparently have decided their SLR collaboration wasn't fun or fast enough, so they've added a convertible and a peppier version of the SLR. Of course, they prefer the term "Roadster" to "convertible" and "722 Edition" to "peppier," but you get the idea. Act fast if you want the 722, as only 150 are scheduled to be built.
Mercedes-Benz joined the supercar segment for 2005 with the SLR McLaren super sport GT coupe, which uses a supercharged 617-horsepower V-8 engine. That engine is the base for the Roadster; the 722 Edition gets a supercharged V-8 that turns out 650 hp.
The SLR features full carbon-fiber monocoque, crash structures and body panels. Mercedes-Benz says the SLR coupe can accelerate from zero to 60 mph in less than 3.8 seconds and top 200 mph. The Roadster, Mercedes-Benz says, can hit a 207-mph top speed and go from zero to 60 in 3.8 seconds, while the 722 Edition hits 100 kmh (roughly 62.1 mph) in 3.6 seconds and is good for a top speed of around 209 mph, according to Mercedes-Benz.
Bringing the supercar to a halt are ceramic composite brake discs and an innovative air brake, standard on all SLRs. Actually an adaptive rear spoiler in the trunklid, the air brake springs up at a 65-degree angle when a driver brakes hard when traveling faster than 59 mph.
Celebrating the legendary SLR racecars of the 1960s, Mercedes-Benz called the coupe a "futuristic interpretation of styling elements" of the original 300SLR, the SLR Uhlenhaut Coupe and the company's Formula One Silver Arrow racecars. Originally, "SLR" stood for "sporty, light racing." The 722 Edition is a reference to the plate of Stirling Moss and Dennis Jenkinson's winning car in the 1955 Mille Miglia road race. (In the race, the cars wore a number that told spectators the time the car started the race — 7:22 a.m., in his case.)
Initially offered in Europe, the limited-production SLR McLaren reached American dealerships in summer 2004. Roadster versions are expected to hit the U.S. in the fall of 2007.
Mercedes-Benz claims the rigidity and strength of the SLR's carbon-fiber composite construction was "never before achieved in road-going vehicles." It's the first production vehicle to use a front crash structure made entirely of carbon fiber, designed to absorb energy at a constant rate.
Mercedes-Benz also claims the Roadster has "extreme torsional rigidity" for a convertible, thanks to the carbon-fiber reinforced plastic material that makes up the body. The roof itself is semi-automatic: You have to unlock the top from the windshield and raise it slightly before the electric motors take it the rest of the way down. Mercedes-Benz says the top can drop in less than 10 seconds, and the car's body is tuned to allow conversation at speeds above 120 mph.
Ceramic brake discs are made of a composite material that promises astounding stopping power, high heat resistance and long service life, Mercedes says. Eight-piston brake calipers are installed in the front, and four-piston calipers are featured at the rear.
Side strakes ahead of each front door recall some of the most potent Mercedes-Benz models of the past. The three-pronged Mercedes-Benz star insignia sits at the front edge of the hood dome and extends into a small triangular lower panel. Flanking the insignia are twin air intakes with single-slat grilles that sit next to round bi-xenon headlights. An immense air intake is closer to the ground.
The Roadster maintains the gull-wing-like door opening of the coupe. It also adds two fixed roll bars. The 722 Edition gets a variety of spoilers, wings and diffusers to improve aerodynamics and set it apart from standard SLRs. It also gets distinct 19-inch wheels and is available with a special gray paint.
Two occupants sit on individually padded carbon-frame seats. Special "Silver Arrow" leather upholstery is available in red, as in the 1950s SLR racecar. Chronometer-style instruments are installed. Interior convenience features include a navigation system and automatic climate control.
Under the Hood
Hand-built by AMG in Affalterbach, Germany, the supercharged and intercooled 5.5-liter V-8 engine sits behind the front wheels in a front mid-engine position. The V-8 generates 617 hp and 575 pounds-feet of torque. The more powerful 722 Edition gets a supercharged V-8 that turns out 650 hp.
Dry-sump lubrication includes a remote oil tank that eliminates the conventional oil pan or sump. This allows the engine to sit lower and creates a lower center of gravity. Dry-sump systems also prevent oil starvation during extremely hard acceleration, cornering and braking.
The five-speed automatic transmission has three programs (Comfort, Sport and Manual) with different shift characteristics. In Manual mode, the driver can use steering-wheel paddles or the TouchShift function on the gearshift lever.
Safety features include innovative knee airbags and door-mounted head and thorax side-impact airbags. The automaker's Electronic Stability Program is standard. In addition to that safety equipment, the Roadster has twin roll bars and steel-reinforced A-pillars.