Mercedes-Benz SL 400 AMG Sport first drive review

The Mercedes SL 400 – the new six-cylinder version of a car as grand as a modern Mercedes SL. Which may seem a conflicted concept to get your head around, even with engine downsizing so key to success for car manufacturers these days. 

Mercedes introduced the current SL two years ago having fitted one of the best V8 engines ever to grace the car to the SL 500, but carried over the lesser 3.5-litre V6 from the last version largely untouched.

Now, the SL 350 becomes the SL 400 – and that aged atmospheric V6 is replaced by a brand new 3.0-litre mill with twin turbochargers and direct injection.

Predictably enough, mid-range torque is what the new engine’s got, and what the old one never really had. The entry-level SL 400 develops more than 80lb ft of extra pulling power compared to its predecessor, and makes all 354lb ft available from just 1600rpm – half the crank speed you needed to get the old V6 to hit full stride.

Mercedes’ claimed 0-62mph sprint is also improved by seven-tenths of a second, to 5.2 seconds.

Fairly fast. You’d bet that in-gear performance is even more greatly transformed than that 0-62mph improvement would suggest.

Response from the pair of turbochargers is good, and the accessible swell of acceleration they create suits the swift, relaxed ground covering that SLs are built to do very well. 

The new engine also works better with Mercedes’ 7G-tronic automatic gearbox than the old V6 ever did, the former still slower and more unwilling to kickdown than competitors’ transmissions.

In outright terms the SL 400 is brisk enough to pick off everyday traffic effortlessly and certainly feels athletic. It isn’t quite as quick as the hotter six-cylinder versions of the Porsche 911 or Jaguar F-Type, but you’d imagine SL owners won’t care.

But, while performance is now where it should be for the bottom-rung version of Stuttgart’s blue-blooded roadster, other facets of the driving experience still need improvement.