The BMW E24 was the first generation of BMW 6 Series grand tourer coupes BMW produced, production of the E24 lasted from 1976 to 1988. It replaced the E9 coupes and was replaced, after a 16-year hiatus, in 2004 by the E63 6 Series. Aside from the M635 CSi, the E24 was powered by a range of M30 straight-6 engines. The E24 M635 CSi (called the M6 in the United States and Japan) is considered the start of the M6 model line. In most markets, the M635 CSi was powered by the M88 straight-6. In the United States and Japan, the M6 was powered by the less powerful S38 straight-6 engine. The initial proposal for the E24 was a based on a BMW E9 3.0 CS with an increased height, in order to make it easier for customers to get into the car. However, Bob Lutz rejected the proposal, eventually leading to the shape of the E24 in its production form. Unlike its E9 predecessor, the body of the E24 had a B pillar. Production started in March of 1976 with two models: the 630 CS and 633 CSi. Originally the bodies were manufactured by Karmann, but production was later taken in-house to BMW. Initially, the E24 was based on the E12 5 Series platform. The M version of the E24, the M635 CSi, was first introd
The M88 engine present in the M635 CSi is an evolution of the 24-valve straight six developed for the mid-engine M1 supercar. Like that engine, the M88 shares a displacement of 3,453cc and has a four-valve crossflow cylinder designed for better breathing at high rpm. However, for its application in the E24 the M88 has wet-sump lubrication, specific pistons and connecting rods, as well as more advanced Bosch Motronic fuel injection/engine management.