The K-series engines are based on the N54B30 twin-turbo engine from the 335i with 306PS (225kW) and 400Nm. From 2007 to 2011, this BMW engine was winner in the prestigious International Engine of the Year awards.

The K2 engine was introduced in the E90 B3 BiTurbo in late 2007. The basic concept of an inline-6 with twin-turbos is reminiscent of the renowned B7/5 engine of the B10 BiTurbo from the early 1990’s.

Modifications include custom Alpina engine block, pistons, exhaust manifold and exhaust. Heat management is improved with a custom additional oil cooler.

In 2010, BMW replaced the N54B30 engine in the 335i with the new generation N55B30 engine. However, Alpina choose to retain the N54B30 engine as basis for the K3 engine. The K3 engine was introduced in the E9x B3 BiTurbo LCI in late 2008.

Changes from the K2 engine are limited. Focus was on improved fuel consumption and emissions. The K3 engine shares components with the E82 1M Coupe.

The K3/1 engine was introduced in the E90 B3 S BiTurbo in early 2010. Changes from the K3 engine include improved cooling and intake parts from the BMW 335is. For the B3 GT3, power is increased by an additional 8PS with an Akropovic exhaust.