BMW X4 review - What is BMW's mini X6 like? - Engine and gearbox

With just two engines and two gearboxes the X4 range is remarkably simple; so much so it almost makes up for the X4's ludicrously complicated naming convention.

The X4 xDrive20d is powered by a 2-litre four-cylinder turbo diesel that produces 187bhp at 4000rpm and 295lb ft of torque between 1500 and 3000rpm. We’re yet to try this engine in the X4, however in BMW’s saloon cars its performance is certainly adequate - even if it does make a relatively agricultural noise. If you can bear the noise and rev the engine right to its redline, it manages to produce some meaningful performance - it's not strained at high revs like most diesels. The four-cylinder is the only motor available with a manual gearbox but the X4, like most SUVs, suits an automatic better.

The six-cylinder engine is smoother, more refined and makes a more pleasing noise. Just like the four-cylinder, the 3-litre delivers good performance across its entire rev range. Sadly, the eight-speed auto’s close ratio gears don’t allow the revs to drop enough between each change to make the most of the low- or mid-range grunt. Instead, the revs remain in a 1000rpm band as you shift up through the gears.

The 30d’s six produces 254bhp at 4000rpm and 413lb ft or torque between 1500 and 3000rpm. The more powerful 35d makes 309bhp at slightly higher revs (4400rpm) but maximum torque of 465lb ft comes in at 1500rpm and is then over by 2500rpm.