What is it?
Mercedes-Benz’s successor to the six-year-old SL55 AMG, the SL63 AMG.
The new two seater, set to reach the UK next month, forms part of a five-strong facelifted SL line-up that also includes the 231bhp 3.0-litre V6 SL280, 316bhp 3.5-litre V6 SL350, 388bhp 5.5-litre V8 SL500 and storming 612bhp twin-turbocharged 6.0-litre V12 SL65 AMG.
As the name of AMG’s latest model suggests, the up-market roadster gets a new naturally-aspirated 6.2-litre V8 that replaces the outgoing model’s supercharged 5.4-litre V8.
Despite a lack of forced injection, the new powerplant’s larger capacity sees it trump its predecessor to the tune of 15bhp, putting out 525bhp at 6800rpm. It can’t match the old engine’s huge torque rating, though; the SL63 AMG’s 450lb ft is 66lb ft down on the SL55 AMG, and is developed some 2550rpm further up the rev range at a high 5200rpm, meaning it has to be worked fairly hard before you see its best.
All this muscle makes its way back to the rear wheels via a new seven-speed paddle shift gearbox. Designed to handle torque loads of up to 516lb ft, the new gearbox offers the choice between four modes; comfort, sport, sport plus and manual – the latter claimed to boast shift times of just 100 milliseconds.
Inside, there’s a new three spoke steering wheel with remote shift paddles, lightly altered instrument graphics, redesigned sport seats with optional Airscarf system as well as a new navigation and entertainment system. The centre console is reworked to accommodate the revised shift lever and its associated switchgear.
There’s also a striking new front end design that, to these eyes at least, provides the SL63 AMG with an instantly more aggressive appearance than the SL55 AMG.
What’s it like?
Vastly more fluent in its actions than the SL55 AMG ever was. While the basic four-link (front) and multi-link (rear) suspension remains unchanged in its basic design, AMG have provided the SL63 with new spring and damper rates as well as altered bushes more rigid front axle bearings.
The steering ratio remains the same as before at 14.5:1, AMG deciding to eschew the variable DirectSteer system that has gone into other facelifted SL models in the interests of a traditional linearity within the helm. While lacking the whip crack action of some open top rivals, the speed sensitive arrangement possesses a reassuringly progressive feel that boosts driver confidence.
The reworked suspension provides more than adequate levels of compliance, but also remains wonderfully controlled on all sorts of surfaces, leading to phenomenal front end grip. Indeed, you can throw this car into corners at seemingly insane speeds and it will retain your chosen line with steadfast assurance. Ride quality, meanwhile, remains exemplary. Yes, it’s firm, but it is never harsh.
Another development is the appearance of AMG’s three stage ESP system – as first unveiled on the C63 AMG last year. It provides the driver a choice between a standard and sport setting – the latter serving up greater slip angles before the onset of individual braking of the wheels. Furthermore, you can now also turn the system off completely – not something I would recommend on public roads but just the thing for track days.
Despite tipping the scales at a hefty 1970kg, the SL63 AMG possesses monumental acceleration in lower gears. Mercedes-Benz claims it will hit 62mph in just 4.6sec. That’s a scant 0.1sec slower than the time quoted for the SL55 AMG strangely enough – a sign, perhaps, that after years of ever sharper straight line performance figures Mercedes-Benz has finally decided enough is enough.
While the new naturally aspirated engine lacks the legendary low end punch of the old supercharged engine, it has broader power band, making it more compelling to drive. Revs build quickly on a planted throttle to provide heady levels of thrust, sending the big two seater down the road at the sort of speed that places it alongside some of the world’s most exotic supercars for standing start performance.
Accompanying it all is a deep baritone exhaust note under load and wonderfully alluring burble on a trailing throttle. Top speed remains pegged at 155mph, though customers opting for the optional performance package, which adds items like a limited slip differential and larger brakes, can have it extended to 186mph.
Dialling up the manual mode sees the gearbox hold on to gears, allowing the engine to run all the way to the 7200rpm redline before the onset of the limiter. In this configuration, the SL63 AMG feels more responsive sportier than the SL55 AMG ever did.
Up shifts, even under full throttle loads, are performed with a satisfyingly positive action – if not quite as rapid or as smooth as the latest double clutch gearboxes. All of which makes you wonder why it has taken Mercedes-Benz so long to provide an alternative to its traditional automatic gearbox.
The electronics have also been programmed to provide a hearty blip on downshifts, allowing you to close down into corners with terrific confidence. Alternately you can stick it in any one of the other modes – comfort, sport or sport plus – and allow the gearbox to do the shifting for you.
Should I buy one?
There’s no doubt about it, the SL63 AMG is a bigger step away from the standard SL500 than the SL55 AMG ever was. The new engine and gearbox endow it with far more sporty traits than its predecessor and this fact alone is going to make it hard to resist for those with the necessary finances.
Those considering the new car, however, would be well advised to look at the performance package, especially the optional limited slip differential, which adds a further dimension to its already haughty dynamic qualities.