Mercedes Benz E350 BlueEfficiency

Smooth, super-refined, a pleasure to drive in our start-stop environment and capable of massive performance when needed, the new diesel motor complements the new E’s character perfectly

Published on Dec 08, 2009 08:00:00 AM

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The new diesel E350 CDI is just so smooth and sweet-sounding even from the outside that anyone could easily mistake it for a petrol-powered car.As most of you are aware, diesel motors have been gaining in popularity because they have been getting more powerful as well as more silent and refined. But the Merc’s updated 3.0-litre V6 takes this even further. There’s no hint of diesel motor rattle, there’s very little vibration and even when you rev it, it’s as smooth as honey mixed with syrup.

As ever, Mercedes engineers have taken what was already a very good motor and improved on it significantly. While much of the OM 624 (OM stands for Oil Motor or diesel) remains common with the previous-generation E280 CDI, Mercedes has both upped the power and also improved fuel economy. In an effort to make it even more refined and silent, the motor’s compression ratio has been reduced significantly from 17.7 to 15.8. And there are new, more responsive injectors for better control as well as improved air flow and ducting in the engine, all of which translate to even greater refinement. This engine develops torque in a more linear manner and has a flatter torque curve too, which can be felt in the effortless manner the car drives.

This all-aluminum 72-degree V6 also makes a commercial vehicle-embarrassing 55kgm of torque from 1600rpm, just off idle, and this allows this otherwise heavy 1825kg car to be blown forward like it’s an ultra-light skiff. It lacks the surge in power you get in the earlier 280 CDI and you miss that spike to a certain extent, but the overall performance is even stronger.

Normal driving conditions need only a gentle dab on the throttle and even that is good enough to have you scooting forward in that effortless, well insulated, typically Mercedes manner. The greater flexibility of the motor also means that the gearbox in ‘Comfort’ setting can shift up gears much earlier, so progress is both rapid and relaxed. However, with 231bhp, the sharp new E can play performance saloon easily as well.

As you take off from rest with full throttle, the E-class’s seven-speed automatic gearbox takes you through the gears in rapid succession, with the passengers pinned back in the seats. Zero to 100kph comes up in a very rapid 7.63sec. The extra gear on the gearbox is put to good use here. Performance continues unabated further up the power band as well, with 0-200kph coming up in 30.47sec. It also helps that you are given paddle shifts, that in both Sport and Comfort settings, are really nice to use, the gearbox responding swiftly enough to requests for a downshift.

The Blue Efficiency badge you see on the wings of the car is the other new feature. Not a single system, but a collection of optimisation measures that together make a significant impact on fuel economy. Our tests show the new E350 CDI is as efficient in the city and much more efficient than the E280 CDI on the highway. The new E BlueEfficiency returned 7.8 kpl in the city and 13.15 kpl in the highway cycle.