|Manufacturer||BMW, Bayerische Motoren Werke AG|
|N63B44||4.4 L (4395 cc)||300 kW (407 hp) @ 5500-6400||600 N·m @ 1750-4500||7000 rpm||2008|
The N63B44 produces 407hp and 600Nm of torque. It features a reverse-flow air design in which the turbochargers are mounted in the engine valley and the intake manifolds are located on the sides of the block. This new design creates a more compact engine package and reduces the width of the assembled engine. The engine uses air-to-water intercoolers, which is more efficient and provides a shorter air path than using a standard air-to-air intercooler. 
Similar to the N54B30, the N63B44 does not use the second generation Valvetronic technology found in other current engines. The principal advantage of Valvetronic is the reduction of intake vacuum, which is not an issue in the pressurized intake found in a turbo-charged engine.