A factory tuned Mercedes-AMG SLS boasting a raft of detailed performance-enhancing solutions gained in part from the company’s successful customer team support engagement in GT racing. The SLS GT is an attempt to make Stuttgart’s traditionally configured front-engined/rear-wheel-drive supercar both a more potent track day tool and a more rewarding back road proposition.
The SLS AMG GT will briefly crown the Mercedes-AMG road car line-up. The gullwing coupé is set to carry a price tag of around £180,000 and the forthcoming roadster is tipped to arrive at £188,000 – in each case a £12,000 premium over the standard SLS. But with the even more extreme SLS Black Series nearing the end of its development period, the SLS GT's reign at the top of the German car maker’s line-up is likely to be short lived.
The SLS GT is outwardly distinguished from the standard SLS by its darkened headlight and tail light lens treatment, the high gloss finish to its grille, exterior mirror housing and bonnet fins, and red brake calipers. Inside, it receives lightly restyled instruments and a more a liberal covering of Alcantara.
Among the detailed mechanical changes over the standard SLS is a lightly fettled engine boasting improved breathing properties. The naturally aspirated 6.2-litre V8 kicks out an added 18bhp, with 581bhp developed at 6800rpm. Torque remains the same, swelling to 469lb ft at 4750rpm.
Accompanying the boost in power is a reworked seven-speed gearbox that uses new, in-house-developed software algorithms for an improved shift action. The dual-clutch unit, supplied by Getrag and located within the rear axle assembly, is described as being more direct and spontaneous on up-shifts in manual mode. It has also been programmed to provide a more pronounced blip of the throttle and double-declutching action during downshifts.
Most of all, it is the changes brought to the suspension that help define the hardened character of the SLS GT.
The double wishbone arrangement with variable damping control retains the same basic geometry and ride height as the SLS, but the elastokinematic properties have been altered to provide the car with a more focused nature.
Despite the suspension upgrade, however, the SLS GT rides on the same wheels and tyres as the standard SLS, with 265/35 profile rubber on 19-inch alloys up front and 295/30 on 20-inch rims at the rear.
The first clue to the SLS GT’s added potency comes the moment you hit the starter button. The reworked engine, which sits well back in the engine bay on the same hydraulic mounts, fires with greater urgency, and as you get up to speed the signature baritone exhaust note is even more alluring than that of the standard SLS.
The naturally aspirated engine lacks the low end explosiveness of other turbocharged mills but it provides tremendous mid-range punch. With a 0-62mph time of 3.7sec the GT is quicker off the line than the standard SLS, but only by 0.1sec in coupé guise. While there’s little to indicate the engine’s added reserves in terms of outright acceleration, the hardcore soundtrack at the business end of the rev range has always been at the root of the appeal of the SLS, and so it is here.
It delivers on the dynamic front, too, in line with the head of AMG development Tobias Moers' assertion that the SLS GT operates on a much higher level than the earlier SLS.
Even at moderate speeds at part throttle there’s a noticeable improvement in the action and overall efficiency of the gearbox, with a crisper and faster action.
This is more apparent on full-bore up-shifts and lunging downshifts, which are fired off in a more efficient action with less of a pause between the declutching of one gear and the engaging of the next.
The improvement has been achieved with the adoption of new software, although there is no word yet on whether it will be made available to existing SLS owners as a running change.
Moers also indicates that AMG has made detailed changes to the SLS’s hydraulically actuated steering. There remains a small area of slack around the straight ahead, but the speed sensitive system is more responsive off centre, and weighting has been wound back a tick at the extremities of lock to give the SLS GT a more fluid and confidence-inspiring character.
With larger diameter anti-roll bars, new bushings and firmer springs and dampers, the ride is stiffer than the standard SLS's and there are greater levels of tyre noise at low and high speeds — none of which adds to the car’s hard-earned reputation as a fantastic long distance proposition.
But hot laps at Hockenheim highlighted that while the underpinnings are altogether less forgiving, they help provide the GT with more neutral handling with lower levels of body roll upon turn-in. That quells the tendency for initial understeer and roll steer out of corners, improving rear end purchase. It feels quite different to the standard SLS.
While there’s less comfort, there is greater control at the extremities. The SLS GT feels sharper and generally more responsive than the standard car. It feels more alive and more urgent, and a good deal more exciting on a suitable section of bitumen.
On a purely emotional level it is among the world’s greatest road cars and right up there with the best that Ferrari, Aston Martin and Porsche can deliver for heart-thumping appeal. In isolation, it is a rabidly exciting car to drive. The changes Moers and his engineering team at AMG have brought to the new car provide a welcome boost in the way the SLS drives.
Just don’t expect limousine-like levels of comfort on public roads.