The range-topping X6 xDrive50i is propelled by an all-new twin-turbo 4.4-liter V8 unit producing 407 horsepower at 5500 rpm and 446 pound-feet of torque between 1750 rpm and 4500 rpm. The sprint to 62 mph takes just 5.4 seconds and fuel economy is estimated at around 19 mpg (U.S. gallons).
The engine is designed as a replacement to the company's current 4.8-liter naturally-aspirated V8. It is expected to filter into other models like the 5-Series, 6-Series and 7-Series in the near future.
The engine seems to represent the second stage in a shift at BMW from high-displacement naturally-aspirated motors to slightly smaller turbocharged powerplants. BMW's twin-turbo 3.0-liter engine that powers the 335i and 135i has been met with overwhelmingly positive reviews, and it appears BMW is hoping for similar results with its new V8.
The X6's other engine is also a twin-turbo setup. The xDrive35i will come with the aforementioned 3.0-liter inline-six from the 335i, producing 306 horsepower.