BMW N55

The N55 is a turbocharged straight-6 automobile engine from BMW. It was launched in early 2009 in the new BMW 5-Series Gran Turismo in the BMW 535i GT model. It is BMW's first production single turbocharged gasoline engine that combines the use of Valvetronic, turbocharger technology and direct injection technology.

Despite the BMW TwinPower Turbo brand name used for the N55, it uses a single turbocharger with twin scroll technology, taking in exhaust pulses from two groups of 3 cylinders. Valvetronic is used to help reduce throttle losses. By contrast, other engines carrying the Twin Turbo moniker have twin turbochargers. The preceding N54 was a twin-turbocharged straight-6 that did not use Valvetronic.

Posted in BMW