Engine and Gearbox
The M178 engine is the dry-sumped brother of the M177 engine found in Mercedes’ new C63. That means it has a displacement of 3982cc and the V8 has two turbochargers residing in the middle of the 90 degree V. In more powerful S form, the outputs are 503bhp at 6250rpm and 479lb ft of torque from 1750 to 4750rpm.
The main reason for moving away from the old naturally aspirated 6.2-litre V8 found in the SLS is of course the industry-wide drive to lower emissions. As such, the AMG GT S’s new turbocharged unit returns a claimed 30.1mpg on the combined cycle although in our experience you would have to be extremely restrained to achieve that.
Subscribe to evo magazine
On both road and track the performance of the AMG GT S never feels anything less than ballistic. Despite being turbocharged, the throttle response is fantastic, punching you out of every corner and actually matching the alacrity of the handling. The V8 then hauls with an unrelenting ferocity down the straights, reeling in the horizon in an almost surreal fashion. With the exhaust button pressed, all this is of course overlaid with a soundtrack that gargles blood and thunder like some sort of tetchy Norse god.
Where fast Mercedes of the past have often fallen a little short is in the gearshift. However, AMG has got it sorted with the GT. The seven-speed dual-clutch ‘box now cracks through upshifts as smartly as you like, but more importantly it will also down-shift when you ask it to. It still can’t quite match a Ferrari ‘box for overall downshift speed and theatre but the mere fact we’re comparing it to that means it is a huge step on.
