The new BMW X5 xDrive50i takes its place as the flagship of the X5 family, yielding 400 horsepower at 5,500 rpm and 450 lb-ft of torque at 1,750 - 4,500 rpm from its twin-turbocharged 4.4 liter V-8 engine. Introduced in the BMW X6 in Spring of 2008, this all-aluminum V-8 features High Precision direct fuel injection, "reverse-flow" architecture for revolutionary responsiveness and packaging, and BMW' s VANOS variable valve timing technology. Together, these features create what may be the perfect balance between high fuel efficiency, low emissions, and the dominant, dynamic performance expected of a BMW V-8. The 0-60 mph sprint is accomplished in 5.3 seconds.