The BMW E12 is the first generation of 5 Series executive cars, which was produced from 1972 to 1981 and replaced the saloon models of the BMW New Class range. Initial models were powered by inline-four engines, using either a carburettor or fuel-injection. A year after launch, the first model powered by a straight-six engine was introduced. By the final years of E12 production, most models used a straight-six engine. There was no M5 model for the E12, however the E12 M535i is considered to be the predecessor to the M5. The E24 6 Series coupés were built on the E12 platform up until 1982. The E12 was replaced by the E28 5 Series in 1981, although the tools were sent to South Africa where E12 assembly continued (with E28 interiors) until 1984. Development At the 1970 Geneva Motor Show, BMW unveiled the 2200ti Garmisch concept car, a 2-door saloon which was developed in conjunction with Bertone. The 2200ti Garmisch concept car was shown as a potential replacement for the New Class saloons and the eventual E12 production model utilized many design elements from the Garmisch. Development of the E12-series had begun by the end of the 1960s, when wind tunnel tests were conducted. Eberhard von Kuenheim, then chairman of BMW's supervisory board, hired French designer Paul Bracq in 1970 to work as the E12's Chief of design, with Marcello Gandini of Bertone as co-designers of the exterior. In 1971, a road-legal E12 prototype, which looked similar to a Fiat 132, was made. Also in 1971, Paul Bracq had finalised the E12's design, however, compared with the later series production E12, Bracq's design car had a more stretched, and dynamic appearance. Computers were used in BMW development for the first time to calculate front and rear crumple zones; the roof was designed with a rollover protection structure. The body has a drag coefficient of 0.44. BMW had previously located turn signal stalks on the right hand side of the steering wheels, and the E12 was their first model to have the stalk on the left side. Before the E12 had been introduced, there were rumours that it would be available with both a 2.2 litre four-cylinder engine, and a small six-cylinder engine. Instead, BMW carried over the 2-litre four-cylinder M10 engines from the New Class saloons, but modified the cylinder heads in order to improve combustion. With the introduction of