The comfortably vast S-class is the first home for AMG’s new bi-turbo V8, and very nicely it suits it, too. The sportiest S-class retains the S63 badge despite the new engine’s 5.5-litre capacity, and it also retains a pleasing amount of the character of the 6.2-litre naturally aspirated V8 that used to fill the gap between the grille and windscreen; fire it up and there’s a suitably thunderous roar from the quad tailpipes.
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The big difference is that the new 536bhp, 590lb ft motor gives the 2.1‑ton S-class the huge and instant shove it needs to make it effortlessly punchy, yet at the same time it is also 25 per cent more economical than the 6.2, delivering an amazing 246g/km CO2 rating.
There are a number of features that contribute to that CO2 figure, including a stop/start function and the AMG-designed MCT seven-speed auto transmission with its low-inertia multi-plate wet clutch. The engine’s a bit useful, too, as you’d expect. It has continuously variable inlet and exhaust cam timing, a demand-controlled oil pump and direct injection using new Bosch piezo-electric injectors which have a finely controllable spray rate and pattern. Those twin turbos play their part, too; less capacity means less friction, and they boost from very low revs, allowing the S63 to hold high gears in the CO2 test cycle.
This characteristic is soon obvious from behind the wheel, the low-register rumble of the V8 as it holds at least one gear higher than you’d select yourself being slightly disconcerting at first. It feels like the engine is out of its comfort zone when in fact it’s being efficient – low revs mean low friction. Clog the throttle and in a moment you’re lunging almost violently down the road, trailing a deep, resonant V8 wail. It’s a real Jekyll and Hyde engine – probably the world’s most efficient V8 but every cubic inch an AMG engine.
The gearbox can feel a little sharp at times, notably as it downshifts when slowing for roundabouts and suchlike, but this ‘edge’ seems to suit the character of the car. It’s a big thing to hustle along and doesn’t shrink around you like a new Jaguar XJ, but it’s tidy and the chassis feels pretty well damped. The steering is a touch heavy and doesn’t deliver much in the way of useful feel, but you can place the S63 with decent accuracy and make very swift progress. You notice its mass much more on the brakes than under power.
For the bigger AMG models, the new bi-turbo V8 brings a welcome return to the days of easy torque. The fact that it comes with remarkable efficiency is, well, remarkable because it doesn’t feel like you’re making any sacrifice. The S63 is quite a weapon and brims with bassy, fruity V8 character. And for those who believe you can never have too much power, there’s the optional ‘Performance Package’, which boosts power and torque to a monster 563bhp and 664lb ft. Those AMG boys are still crazy.
|Engine||V8, 5461cc, twin-turbo|
|Max power||536bhp @ 5500rpm|
|Max torque||590lb ft @ 2000-4500rpm|
|Top speed||155mph (limited)|