The vast majority of BMW X5s sold in the UK are powered by a 3.0-litre, six-cylinder turbodiesel. They're all automatic, too; there’s no longer a manual X5 transmission option.
In 2010, new engines were launched for the xDrive30d, xDrive40d and xDrive50i, with the latter two models replacing the xDrive35d and xDrive48i respectively.
The entry-level xDrive30d was upgraded to produce 241bhp, up 10bhp on the previous xDrive30d, while 0-62mph acceleration was trimmed to a claimed 7.6sec. The unit was also made more frugal, putting combined cycle economy at 38.2mpg, equivalent to 195g/km of CO2.
At 241bhp, the entry-level engine in the X5 xDrive30d is one of the more powerful in its class, and it gives this SUV a healthy turn of speed. We recorded a 0-60mph time of 7.9sec, and there’s a broad spread of power throughout the rev range. Peak torque of 398lb ft is developed at 1750-3000rpm, so response from low revs is excellent, too.
The replacement of the xDrive35d with the xDrive40d also brought performance gains, with the 0-62mph time dropping from 7.0sec to 6.6sec, thanks to a power output boosted by almost 20bhp.
The twin-turbo diesel engine is a gutsy device, with a flexible delivery and excellent refinement – all of which makes it perfectly suited for duty in a big luxury 4x4. A prodigious 442lb ft of torque arrives early in the rev range to make light work of the xDrive40d's weight, endowing it with excellent step-off, solid in-gear shove and a good turn of speed.
The twin-turbo 4.4-litre V8 petrol engine in the xDrive50i (the same unit is also seen in the 7 Series) pumps out 402bhp and provides startling performance, reaching 62mph in just 5.5sec.
With a fat 443lb ft of torque from 1750rpm, the xDrive50i is as flexible as the best diesels but also wonderfully smooth and crisp. It sounds nice, too. When viewed on its own merits – ignoring consumption figures compared with the more frugal diesels in the range – this xDrive50i is quite magnificent.
If the xDrive50i's performance doesn't set your pants on fire, the only car for you will be the shockingly rapid X5 M, a leviathan designed to tempt buyers away from the Porsche Cayenne Turbo.
The BMW's 547bhp sounds impressive enough; more startling is the 502lb ft of torque, which is available from just 1500rpm right up to 5650rpm. That’s enough for the X5 to crack 0-62mph in 4.7sec and reach a limited top speed of 155mph.