BMW M1 Group 4 sponsored by Marlboro - 24 Hours Le Mans 1980
Marking / livery in 1/24 scale manufactured by Renaissance Models (ref. TK24-333, also TK24/333)

The appearance of the Group 5 category was the trigger that led to the birth of the “M1” program in the mid-1970s. Jochen Neerpasch, CEO of BMW Motorsport, was responsible for initiating this ambitious project, whose initial objectives were that of facing Porsche in the World Championship for Manufacturers and, as a culmination, winning at Le Mans.

But in 1977, halfway through the development of the M1, FISA changed the regulations and decided that 400 cars would have to be built to allow Group 4 homologation to move up to Group 5. Faced with this problem, Jochen Neerpasch met Max Mosely, and the two came up with the idea of pitting the five fastest Formula One drivers from Grand Prix practice to race in a series of virtually identical BMW M1 Procars against a selection of the world's best touring car drivers. Having convinced Bernie Ecclestone and the Formula 1 world of the idea, the BMW board of directors approved the budget to build 25 M1 Procars for the first race at Zolder in 1979. It was a well-organized and ingenious marketing exercise for the brand, also helping in the construction of the M1 necessary to achieve homologation. The Procar series was a win-win: viewers were able to find the answers to the perennial question of whether the outcome depends on the car or the driver, while BMW got more publicity for the brand and its M1 model.

The Giugiaro-designed fiberglass coupé body wrapped around a multitubular chassis. The engine was a race-developed version of the BMW 3.5-litre six-cylinder, with double overhead camshafts and four valves per cylinder, now with engine code M88/1. Engine power was increased from the 273 hp of the production model to more than 470 hp, with a rev range above 9,000 rpm. The transmission kept the ZF casing, but had multiple gear ratios and its own oil cooler. The suspension was all new with adjustable stabilizer bars, and over the body were mounted flared wheel arches, a much larger front spoiler, and a large rear wing for downforce. The total weight of the M1 Procar was 1,000 kg, 360 kg less than road cars.

The M1 Procar championship races took place over two years, 1979 and 1980, and its level is reflected by meeting the champions of those two seasons, none other than Niki Lauda in 1979 and Nelson Piquet in 1980. After BMW complied with homologation requirements for the M1 to be accepted into the Group 4 category of the World Endurance Championship, several teams used M1 Procars in the championship. In addition to European events, BMW M1s dominated the 1981 IMSA GTO series in the US.