Mercedes C 250 CDI BlueEfficiency

What is it?

The greenest C-class yet. The C 250 CDI BlueEfficiency, to give it its slightly convoluted full name, which uses a brand-new twin-turbocharged, four-cylinder common-rail diesel engine.

Don’t believe the badge on the boot: the C 250 does not run a 2.5-litre engine. Rather the ‘250’ nomenclature indicates that the engine sitting up front is the most powerful version of Merc’s four-cylinder, twin-turbocharged 2143cc common rail diesel engine. The new powerplant delivers 201bhp at 4200rpm, along with a prodigious 369lb ft from just 1600rpm.

What’s it like?

The key to the performance is low-end torque, something the C 250 possesses in spades. There’s no need to work the engine hard – just keep it percolating along somewhere between 1500 and 3500rpm and you’ve got plenty of thrust.

Thanks to the two different sized turbochargers, the power delivery is linear and smooth all the way to the red line, making the C 250 feel more like a big capacity six-cylinder engine, and giving some genuine reason to explore the outer limits of the rev counter.

Merc claims a 0-62mph time of 7.0 seconds, but with all that pull and an ability to rev to 5200rpm it feels much livelier off the line and through the gears than this figure suggests. It’s also powerful enough to warrant fitment of the familiar 155mph electronic speed limiter.

Refinement is impressive, generating nothing more than a distant murmur and very little characteristic diesel vibration at motorway speeds.

But it’s economy that really sets the C 250 CDI apart. Mercedes claims a combined cycle average of 54.3mpg, thanks to low rolling resistance tyres, underbody cladding, low-drag door mirrors and a standard six-speed manual gearbox. Impressive enough, although we saw an indicated 70.6mpg showing on the trip computer after a motorway run.

Should I buy one?

Why not? With fuel consumption figures like this, it’s hard not to be impressed. Factor in the C 250 CDI’s solid performance, unruffled ride and excellent refinement you’ve got a very enticing package.