BMW's most efficient 3 Series driven

* New 320d Efficient Dynamics saloon * CO2 emissions of 109g/km * On sale in January...

BMW's most efficient 3 Series driven

The new BMW 320d Efficient Dynamics saloon is the most efficient 3 Series ever.

We've driven it and can confirm that for all its 'green' credentials it's a 3 Series through and through. Chances are, it could end up being one of the most popular models in the range.

What's new?

The 320d Efficient Dynamics saloon has a number of changes over the standard car, all in the interests of lower fuel consumption and CO2 emissions. Thanks to these, it emits just 109g/km of CO2 and averages 68.9mpg.

As youd expect, the new model has the same range of BMW Efficient Dynamics features that you'll find on any 320d. These include an engine stop-start system, brake energy regeneration and electric power steering.

On top of those, the Efficient Dynamics saloon has:

• Longer gearing
• Lowered suspension
• Aerodynamic alloy wheel designs
• Michelin Energy Saver tyres
• Modified gearshift indicator settings
• A new flywheel

As with the standard 320d, the Efficient Dynamics model has a 2.0-litre diesel engine, but with 161- rather than 175bhp. Maximum torque is up, however, from 258lb ft to 266.

What's it like?

The good news is that the new model is as brilliant to drive as any other 3 Series. Because of the improved torque, you don't notice the drop in power and acceleration is strong.

The lowered suspension doesn't damage the ride quality, either, and the steering and handling are as sharp as ever.

Here's the clever bit. The longer gearing keeps engine revs low to cut fuel consumption and this works in tandem with the new flywheel that helps to smooth out the vibrations that you'd normally expect when the engine is barely above tickover.

BMW reckons that most drivers will, on average, be using 500rpm less than a standard 320d driver and, on the evidence of our brief drive, that's entirely possible. Cruising at a steady 70mph, the car's trip computer showed that we were achieving an average of around 70mpg.

Tax advantages

The changes make the Efficient Dynamics model much cleaner than the standard 320d, which averages 58.9mpg and emits 128g/km. Its even more efficient than the recently-launched 316d, which emits 118g/km and averages 62.8mpg.

As a result, the 320d Efficient Dynamics saloon will cost just 35 a year in road tax and falls into the lowest category for company car tax.

For the moment, the new technology will be used only for this car - bespoke Efficient Dynamics versions of BMW's other models aren't in the pipeline. BMW says that similar features 'might be a strategy' for other models within the next two to three years, however.

Lots of standard kit

The 320d Efficient Dynamics saloon will have standard equipment that mirrors the 320d SE's, but with 16- rather than 17-inch alloy wheels. Standard kit includes dual-zone climate control, reversing sensors, multi-function leather steering wheel and extended lighting.

Apart from the new wheels and slightly lower stance it'll look just like any other 3 Series, too, although there'll be Efficient Dynamics badges on the bootlid and inside.

The price will be equivalent to the 320d SE's, too, which currently costs £26,680. The new 320d Efficient Dynamics saloon goes on sale in January, with first customer deliveries expected in March.