The E24 was a replacement for the CS and CSL coupés first produced in 1965. The CS 3.0 was almost changed by adding a few centimeters in height to make it easier for customers to get into the car. However, Bob Lutz rebelled against the decision and rough drafted an alternative version that soon became the 6 series. Production started in March 1976 with two models: the 630CS and 633CSi. Originally the bodies were manufactured by Karmann, but production was later taken in-house to BMW.
In July 1978 a more powerful variant, the 635CSi, was introduced (for the time being not available in North America and Japan) that featured as standard a special close-ratio 5-speed gearbox and a single piece black rear spoiler. The bigger bore and shorter stroke facilitated max 218 hp at 5200rpm and a better torque curve. For the first year, the 635CSi was offered in three colors (Polaris, Henna Red, Graphite), and could also be spotted by the front air dam that did not have attached fog lights. These simple cosmetic changes reportedly worked to reduce uplift on the car at high speeds by almost 15% over the non-spoiler body shape. This early model shared suspension components with the inaugural BM
left-hand-drive bmw 635 csi 83 red 5-speed manual 1983 german rwd 6-series 2wd