What is it?
The xDrive50i is now the fastest and most powerful of the mainstream (non-M division) BMW X5s, powered by the new 402bhp, twin-turbo 4.4-litre V8 also seen in the 5-series and 7-series.
Replacing the previous 350bhp naturally aspirated 4.8-litre V8, the twin-turbo unit is fitted as part of the latestround of upgrades for the X5 range, which also includes refreshed front and rear styling and more kit.
Linked to an eight-speed automatic gearbox, the new V8 not only brings a hefty increase in power and torque compared with its predecessor but also improved fuel economy and compliance with Euro5 emissions standards.
What’s it like?
It almost goes without saying that buying a thirsty twin-turbo petrol V8 SUV in the UK is foolhardy when the diesel versions are so outstanding in their own right and so much cheaper to run, but let’s just assume that nothing else will suffice. When viewed on its own merits, this new xDrive50i is quite magnificent.
As well as being supremely refined, the twin-turbo V8 gives the X5 startling performance; 5.5sec to 62mph makes it one of the very quickest SUVs on sale, bettered only by the much more expensive Porsche Cayenne Turbo, Mercedes ML63 and BMW’s own X5/X6M. 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.
Although more efficient than its 4.8-litre predecessor, the new V8’s combined 22.6mpg and CO2 output of 292g/km don’t make great reading when the superb, equally torquey xDrive40d achieves 37.7mpg and 198g/km of CO2, but there’s some consolation in the fact that the V8 BMW is less profligate than other big petrol SUVs such as the Range Rover Sport Supercharged and Infiniti FX50S.
In SE spec the X5 has a relaxed and comfortable ride for a BMW, but its chassis struggles to match the xDrive50i’s searing performance, with a little too much roll and a lack of composure when pressed. If recent experience of the xDrive40d M Sport is any indication, the tighter body control that comes with the sports suspension is just about essential on a car as fast as the xDrive50i.