In the 330d, BMW’s B57 engine straddles the fine line between sporting performance and real-world usability with such impressive poise that it’s easy to lament the tax-motivated move away from powerful diesel engines in cars such as these.
Its performance on a cold, wet day on Millbrook’s mile straight helped prove its effectiveness. With BMW’s xDrive four-wheel drive system all but rendering wheelspin off the line non-existent, the 330d hit 60mph from rest in just 5.5sec before reaching 100mph in 14.5sec. Bearing in mind the conditions, as well as the fact that our test car was fully fuelled, BMW’s claimed 0-62mph time of 5.5sec seems entirely believable.
In-gear performance and flexibility are equally mighty, with proceedings becoming faintly strained only once the engine spins past 4000rpm. The manner in which the bulk of torque comes on tap is easily manageable, too. The BMW might not surge forward with quite the level of explosiveness of an Audi S4 TDI, but its slightly more laid-back swell of force serves to make it seem more drivable. That said, a marginally more responsive accelerator pedal, particularly when stepping off the mark, would be welcomed.
The engine’s muscular, bassy growl is by no means a match for the six- or eight-cylinder petrol engines you find elsewhere in BMW’s own four-door line-up or the wider class in general, but the noise it emits under load has an appeal all of its own. In addition to sounding better, those aforementioned petrol saloons will also go a little faster than the 330d, but how many could get close to matching its 42mpg fuel economy test average, or its 52.6mpg touring economy result? Volvo’s plug-in hybrid S60 T8 Polestar Engineered option would get closer than most, but even that car couldn’t better 40mpg on our touring economy test.
For all the praise, however, the report card for the 330d’s powertrain isn’t completely blemish free. The eight-speed gearbox can demonstrate a mildly frustrating hesitance when asked to kick down in Comfort mode, although generally it executes shifts in a slick enough fashion. It can also feel a touch too eager to engage when moving away from a standstill, resulting in a slightly more forceful step-off than is entirely comfortable if you’re hasty with your right foot.