The latest addition to the German car maker’s growing line-up is based on the already potent X7 M50i. Changes include a heavily revised engine and gearbox, tweaked suspension and brakes, and all the usual up-market Alpina cabin accoutrements, including the option of either a six- or seven-seat layout.
As roomy and luxurious as the XB7 is, it is its engine that is the star of the show. The twin-turbocharged 4.4-litre V8 petrol unit gets larger twin-scroll turbochargers, two additional water coolers, reworked intercoolers and a stainless-steel exhaust. Power is up by a not insignificant 90bhp at 623bhp, while torque increases by 37lb ft to 590lb ft on a band of revs between 2000 and 5000rpm.
To put this in perspective, the Bentley Bentayga W12’s twin-turbocharged 6.0-litre W12 engine delivers 600bhp and 664lb ft of torque between 1350 and 4000rpm.
The X7 M50i’s eight-speed automatic gearbox has also been reworked with Alpina’s Switchtronic paddle shift program, a new aluminium oil sump and new mapping – all aimed at speeding shifts and ensuring it can deal with the higher levels of torque. BMW’s xDrive four-wheel drive system has also been subtly revised with new program maps.