Mercedes-Benz S63 AMG driven

You would never have accused the Mercedes-Benz S63 AMG of being a lightweight in the performance stakes, so the decision to slot in a new direct-injection twin-turbo 5.5-litre V8 engine in place of the 6.2 V8 might seem to be gilding the lily. Power rises from 519bhp to 537, and torque from 465lb ft to 592.

Method in the madness

Theres more to this than the cravings of a bunch of power junkies, though. AMG, Mercedes' performance division, plans to cut average CO2 emission by 30% by 2012, and this new engine is a big help. The S63s official economy figure is now an impressive 26.9mpg, a vast improvement on the 19.5mpg with the old V8, while CO2 emissions tumble from 347g/km to 244g/km. Aiding the cause are a new seven-speed automatic gearbox with a wet clutch instead of a torque converter, and a stop-start system to shut off the engine when youre stationary.

More refined, but equally explosive

This isnt just about keeping the emissions police at the EU happy, though. That old V8 could be a bit of a drama queen, mean to share out its torque at some points in the rev range, then too generous at others. Despite the massive increase in torque with the new engine, it arrives more progressively and makes the car easier to drive.

You'll appreciate that on a damp road. The new transmission helps distribute it all smoothly, too. Don't fret, though: the performance is still explosive when you want it to be, accompanied by appropriate sounds from the tailpipes. It sounds like the start of the grouse-shooting season when you back off.

Oh, and if the standard engine isnt brawny enough for you, theres a performance package that ups power to 563bhp and torque to 666lb ft, without hurting economy or emissions. It costs 7890, but they do throw in an AMG driving course.

What Car? Says

Still mad, but now less bad

Roger Stansfield