| First Drive | Munich, Germany | BMW 320d EfficientDynamics saloon |

To test the acceptability of a car that foregoes some of its performance and dynamics in return for even more efficiency, BMW has developed the EfficientDynamics saloon, based on the company's best-selling 320d. There's no arguing with CO₂ emissions of 109g/km and a combined consumption figure of 68.9mpg, but is that achievable while retaining the 320d's all-round ability and appeal?

In the Metal

The only obvious indicator that this car is the EfficientDynamics model will be a set of bespoke 16-inch 'aero' alloys. Sure, there'll be a sticker on the rear window and the ride height is 15mm lower, but few will notice. That's partially the point of course and those wheels actually reduce drag. Look really close and you'll see they're shod with the latest generation of low rolling resistance tyres.

What you get for your Money

As this car won't go on sale until early next year there are no firm prices as yet, but incredibly, BMW aims to sell the EfficientDynamics saloon at the same price as the standard 320d SE and its specification will be on a par with that model. The major difference though is that buyers won't have the option to add M Sport styling, larger alloys or an automatic transmission. Hence the SE and M Sport models will carry on unchanged and the EfficientDynamics version will be for those with running costs high up their list of priorities.

Not only should there be reduced fuel bills, but Vehicle Excise Duty (VED) will be cheaper by two tax bands in the UK and business and fleet buyers could save a packet. In Ireland, it's likely that the new car could actually be cheaper than the current 320d, due to the country's taxation legislation that includes a significant purchase tax (Vehicle Registration Tax, or VRT) calculated according to the level of CO₂ emitted.

Driving it

Without doing a direct back-to-back comparison between the regular 320d and the EfficientDynamics variant it's not easy to quantify how different they are, but that's undoubtedly a good thing. On paper, the new version's performance is diminished a little, with 161bhp on tap rather than the full-fat 174bhp. Offsetting that in part is a higher torque figure of 265lb.ft (versus 258lb.ft). The 0-62mph time is extended from 7.9- to 8.2 seconds, though that is still significantly faster than any other car boasting similar fuel efficiency. The 320d's smooth surge of torque in the mid-range is retained and the engine is as happy to rev as ever, though there's little benefit in using the top quarter of the rev counter.

In ride and handling terms, this 320d feels as wieldy as ever and no less comfortable, with no obvious downside to the lower ride height. There was some additional road noise on our test route - presumably created by the new low rolling resistance tyres, but we'll need to try them on more road surfaces to confirm that.

In fairness, I think most drivers would struggle to tell this car apart from a regular 320d from behind the wheel, which is the biggest compliment we can pay it.

Worth Noting

Although BMW has tweaked virtually all aspects of the 320d - including the aerodynamics, engine and tyres - it's perhaps the transmission that deserves the most attention. Along with lower internal friction and a higher final drive ratio a dual-mass flywheel with a centrifugal-force pendulum is fitted. This is a relatively simple mechanical device that essentially balances out vibrations at low engine speeds, meaning the driver will naturally use lower revs in each gear without feeling like they really should change down. This brings big potential fuel economy gains and has enabled BMW to change the shift points on the gearshift indicator to encourage drivers to utilise the lower engine speeds. Apparently, if the combined cycle was carried out using the in-dash gearshift point indicator as a guide, the figure of 68.9mpg could be improved upon even further.

Summary

BMW is cautious about take-up of this version of the 320d, openly admitting that 'it's not for everyone'. Although the UK will take over 60 percent of the 320d EfficientDynamics saloons made, it still reckons that it'll be considerably outsold by regular SE and M Sport versions. We're not convinced. The potential savings are huge, yet the compromises are few. Pity we have to wait until March 2010 for it to arrive.