BMW 3-Series: Maximum range

Slow and steady...

Fuel economy on paper is one thing. But in real life it's incredibly difficult to achieve the figures that car makers claim. For instance, BMW says the 318d is possible of 60.1mpg - a figure that includes both town and motorway driving.

So far I've struggled to get above 55mpg - and that's with some careful driving. In theory it's actually possible to achieve 806 miles on a single tank in the 318d. So I've set myself the challenge of seeing how far I can make it on one 61-litre tank of diesel.

The name of the game is to drive as efficiently as possible, so I've been strictly adhering to the gear shift indicator and a self-imposed 60mph limit - faithfully followed even on motorways.

Thinking ahead

But it soon became clear that to maximise fuel efficiency, averaging 56mph in sixth gear was the answer. However, my commute is hilly, twisty and often clogged with traffic. The only way to improve efficiency is to adopt a flowing style that avoids any hard acceleration or sudden braking.

So I've been planning ahead much more when driving, especially when approaching roundabouts, to avoid having to stop. Instead, lifting off the power and approaching smoothly has been my strategy, along with avoiding changing gear unneccesarily.

And the result? 698.4 miles exactly. On filling up at the petrol station, the pump showed 62.21 litres, the extra capacity taken up by the neck of the fuel tank. The onboard computer had proved pretty accurate, telling me I had run out two miles before rolling onto the garage forecourt!

Current mileage: 6138

Average mpg: 52.7