Like all thinking car marques BMW is working hard at lowering emissions and fuel consumption. Unlike others, it has been doing so for decades, thus giving it a head start in today’s enlightened world.

But BMW has made a determined decision that low emissions should not get in the way of performance and, even more importantly, driving enjoyment. It learnt this lesson to its corporate embarrassment back in the mid 1980s when it introduced a special economy petrol engine which concentrated on providing high torque – but not much else. While these ‘eta’ engines did trim something off their fuel usage they were terrible things to drive. Would you believe a redline at 4600 rpm – in a six-cylinder petrol BMW?

Anyhow, the lesson has been learned and BMW vows that never again will driving pleasure be dulled simply to make an engine clean. The result is cars like the BMW 120d six-speed manual in which we have just enjoyed an enthralling day of competitive driving. The brief was simple, drive from BMW's Melbourne head office to Philip Island raceway and back. The road sections of the road test were to be done at normal speeds, but with an emphasis on economy driving. While at the track we would undertake several high-performance tests.

The BMW 120d has an official fuel consumption rating of just 4.8 litres per hundred kilometres. With 130 kW of power and 350 Nm of torque it leans towards the performance end of the scale, but that fuel consumption is impressively low.

As one of the competing motoring journalists, and an economy driver of many years standing (with multiple entries in the Guinness Book of Records) I decided to push for minimum fuel use on the trip to the track and to drive back in the way most thinking drivers would. That is with economy in mind, but not taking precedence over all else.

 

Our drive to Philip Island wasn’t done straight down the freeway, but rather on a detour through the sort of interesting roads that appeal to keen drivers. I managed to get the consumption down to just 4.0 litres per hundred, an irritating figure as I had had it sitting at 3.9 litres for quite a while until I managed to get lost and had to do some U-turns and backtracking. Oh, well!

By the way, 4.0 litres per hundred kilometres is an amazing 71 miles per gallon in the old money.

There's more to the BMW's low fuel diesel consumption than simply advanced technology. It also has a stop-start feature that turns the engine off when the car comes to a standstill and you disengage the clutch. The engine is then using no fuel and producing no pollution. It restarts as soon as you push the clutch pedal down again. You can hear it starting, but it's smooth and after the first few times I found myself barely aware that it was happening.

The most important economy feature of all is an indication on the dashboard of when you should change up and down gears. Most drivers of manuals, indeed virtually all of us, tend to hold onto lower gears far longer than is necessary, and thus use unnecessary fuel. BMW says this simple feature can give a bigger saving in fuel than any other of the new technologies it has added to the car.

Philip Island in a BMW is always a fun experience and we were able to fang the cars hard and fast through a couple of disciplines, a slalom and a motorkhana. The little 120d is a neat vehicle for this sort of driving, being compact and light and therefore very responsive to the steering and throttle inputs. We didn’t measure fuel consumption during this testing, deliberately so because the whole idea of these exercises was to forget economy and instead appreciate the car to its full potential.

 

As mentioned, on the way back I drove the BMW 120d in a normal manner. It used 4.6 litres per hundred kilometres, about 15 per cent more than on the full-on economy push on the way down. Its average speed was almost 10 per cent higher. But driving in this normal way isn't as hard on the body or mind, so it's probably the way we advise you use the car.