BMW X7 review – engine and gearbox
More than just an X5 XL, the X7 adds luxury, a little more space and a satisfying driving experience
The engine range comprises of two flavours of the six-cylinder B57 diesel engine; the single-turbo 261bhp version in the xDrive30d, and the four-turbo 394bhp offering for the M50d. There's also a 340bhp B58 six-cylinder 40i model, and the range-topping M50i, all of which are hooked up to the eight-speed automatic gearbox and four-wheel drive as standard.
The six-cylinder, 3-litre diesel is hardly new, having first appeared in the current-generation 7-series, but it continues to make a strong case as the best balance in terms of cost, performance and fuel consumption. It is quiet and refined at low revs or when cruising, fading into the background amongst other low-level noises, but when pressed it provides a pleasing multi-cylinder chorus that is not dissimilar to that of the petrol version. Unobtrusive when required but engaging when you want it, the xDrive30d delivers the required performance to compete with key rivals in the sector.
The petrols are typically less suited to the X7's bulk, not to mention significantly more thirsty, however the 523bhp M50i's twin-turbo V8 is shared with the unit found in other M50i models in the range, and feels good for more than its quoted 523bhp, even if it has nearly 2.5-tons to cart around.