On a passenger ride in the range-topping 577bhp sports car, we recorded a lap time of 7min 46sec while being driven by Thomas Jaeger, one of the GT R’s principal development drivers. AMG insiders are now suggesting that a full-speed run will be between 20 and 25sec quicker than that. If achieved, that would put the GT R close to the 7min 20sec time of the 13.9-mile circuit that the Porsche 911 GT3 RS claimed last year, and maybe even the 7min 18sec set by the revised 911 Turbo S.
There’s no doubt that the GT R will become the fastest car in Mercedes’ line-up when it goes on sale later this year. Frank Emhardt, the car's development boss, reckons that we should see a Nordschleife lap time as being a better metric of overall performance than the car’s straight line performance numbers (an impressive claimed 0-62mph time of 3.6sec). “It is probably the toughest overall test for any performance car,” he said of the Nürburgring.
Emhardt was reluctant to break down exactly where the GT R’s performance advantage over the existing GT S – which has posted a 7min 40sec Nordschleife lap time – comes from, arguing that the improvement comes from the whole package: “it’s definitely the combination: the aerodynamics, and especially the active aero, the chassis revisions, the rear-steering and the weight reduction.”
The GT R's rear wheel steering system is a first for a Mercedes sports car, but works on the same principle as those used by rivals including the Porsche 911 Turbo. The GT R's rear wheels can be moved by up to 1.5 degrees in each plain, steering in the opposite direction to the front wheel at low speed to improve agility and moving in the same direction as the steered wheels at higher velocities to make the car feel more stable.