Mercedes S 250 CDI BlueEFFICIENCY: Paris Motor Show 2010

Mercedes S250 CDI BlueEfficiency. Door graphics optional.

It’s taken a while (or we’re just too good) for Mercedes to make reality our story that the world was going to get a four-pot S-Class – the Mercedes S 250 CDI BlueEFFICIENCY. For buyers – like me – used to opting for an S-Class with a nice V8, the idea of a 4-pot, diesel S Class is a bit of a joke. But actually, it’s not.

Mercedes has brought along to Paris the S250 CDI BE which gets equipped with the same 2.2 litre diesel lump that crops up all over the Mercedes range. Here, with two-stage turbocharging, it delivers 201bhp which will shift the not inconsiderable bulk of the S250 to 60mph in around 8 seconds.

The 2.2 litre diesel is mated to a G-Tronic Plus 7-speed auto ‘box. But this setup is also fitted with ECO Stop/Start which means that whenever the S250 stops, and the driver has their foot on the brake, the engine will stop. It will restart the instant your foot comes off the brake or goes on the accelerator.

Thankfully, you can turn the stop/start off and it won’t be operational if you have the S250 in ‘S’ or ‘M’. And actually, although Stop/Start in a manual is a wast of space unless you drive like a learner, stop/start in an auto needs no such back ward step by the driver to yield real benefits, especially in heavy traffic.

All of which adds up to an S Class which will do 48mpg and emit just 149g/km. Not only that, but with the clever two-stage turbocharging it’ll actually feel pretty decent to drive. True, it’s hardly a V8. But we can get carried away with what we perceive as acceptable in a car like an S Class.

The fact is that this seemingly weedy 2.2 litre diesel engine offers performance which is superior to the 1990s W140 V8 S420. The S420 managed 20 mpg but the S250 averages nearly 50mpg. The S420 took 8.3 seconds to 100kph, the S250 is  a tenth quicker. And the S420 managed to deliver 295lb/ft of torque, but the S250 can muster 369 lb/ft.

It messes with all your preconceptions. It must be black magic trickery.

By Cars UK