About BMW M635 CSi (E24)
BMW installed the M1's supercar powerplant in the engine bay of a 6 Series, upgraded its brakes and suspension, and that's how one of the most iconic German vehicles was born in 1984: the M635 CSi.
The M-badged version was more powerful and luxurious than the rest of the 6 Series range. It was also more expensive than its stablemates and costlier than the M5, which was a four-door sedan powered by the same powerplant. The carmaker started to produce it in 1984, and the updated engine added more than 60 ponies over the regular 635 CSi. Furthermore, the carmaker used this version as a base to compete successfully in racing.
Even though it sported the same shape as the rest of the 6 Series range from 1977, this M version was slightly different. At the front, the four headlamps were available with wipers and washers. Underneath the chromed bumper, BMW installed a lower spoiler that minimized the ground effect. In addition, it installed a set of rectangular fog lamps. It also came standard with BBS light-alloy wheels.
Inside, the dashboard tilted toward the driver, the bolstered front seats, and the individual chairs for the rear-seated passengers were all unique for the 6 Series. Yet, the M version raised the bar a little bit more by adding standard leather upholstery and an onboard diagnosis system. That was unusual. BMW offered the vehicle with a standard tape player and air conditioning. The sunroof was an option, though.
Its engine was carried over from the magic BMW M1. But thanks to the electronic fuel injection system, the M88/3 inline-six powerplant provided more power than the carmaker's first supercar. Power was sent to the rear wheels only via an LSD.