Customers will be able to order the racing version of the SLS AMG this autumn, for deliveries in time for GT3 events in 2011 – including the Spa 24 Hours and Nürburgring 24 Hours.

While FIA GT3 regulations allow very little modification to the road car’s AMG 6.3-litre V8 engine, the acceleration figures for the racer benefit from its lower weight – hence 0-60mph is dispatched in 3.7 seconds. Top speed depends on the chosen gear ratio, but is claimed to be more than 186mph. As with the road car, the GT3’s engine has a dry sump, which not only ensures reliable lubrication under high lateral acceleration but also allows for a low mounting position for the V8 power unit. Unlike the road-going SLS AMG, the GT3 is fitted with six-speed racing transmission, sequential shift and steering-wheel-mounted paddles.

But the most obvious developments are aerodynamic changes and weight reduction. The road car’s long wheelbase, low centre of gravity and wide track are already well suited to track driving, but the lightweight aluminium chassis with all-round double-wishbone suspension has been modified to take the lower vehicle height into account. Meanwhile, the front of the GT3 features a new front skirt with enlarged air intakes. The carbon front splitter runs directly into a smooth underbody panel – and continues seamlessly up, into the rear diffuser. No shortage of downforce, then… particularly when you consider the utterly huge, adjustable, carbon spoiler. Also at the rear, the new skirt houses two openings for extracting air from the rear wheelarches.

The 18-inch wheels prescribed by FIA regulations are not compatible with the AMG high-performance ceramic composite brake system (available as an option on the road car). Hence cast iron axial and radial floating discs are fixed to an aluminium hat via stainless steel composite elements – all four discs being ventilated, slotted and drilled, with six-pot fixed calipers on the front and four-pot at the rear. ABS with special race-track settings is fitted as standard.

Beneath those gullwing doors, the interior of the SLS AMG GT3 is predictably functional. There’s a racing bucket seat, a six-point harness and the HANS system – plus, of course, a steel rollcage. But it’s not entirely Spartan. The racing car retains styling elements from its road-going sibling, such as the distinctive air vents with adjustable cross-shaped nozzles, so evocative of a jet engine.

Text: Charis Whitcombe
Photos: Mercedes-Benz