The BMW M1 (model code E26) was a mid-engine sports car produced by BMW from 1978 to 1981. Its development was unusual: BMW Motorsport initially partnered with Lamborghini to manufacture the car in sufficient quantity for homologation in Group 5 sports car racing. Gianpaolo Dallara designed the tubular steel space frame chassis, but Lamborghini's deteriorating financial position forced BMW to take back production in April 1978, after seven prototypes had been built. A group of former Lamborghini engineers — organised as Italengineering — completed the car's engineering.
The fibreglass body was styled by Giorgetto Giugiaro, drawing on the 1972 BMW Turbo concept car. Final assembly was carried out by hand at German specialist manufacturer Baur in Stuttgart, with the M88/1 engine units supplied from Munich. Only 453 production cars were built: 399 road-going units and 53 motorsport examples.
The road car's 3,453 cc (3.5-litre) M88/1 straight-six engine, developed by Paul Rosche, used Kugelfischer-Bosch mechanical fuel injection, twin overhead camshafts, four valves per cylinder, and six separate throttle bodies, producing 277 PS (204 kW; 273 hp) at 6,500 rpm with 330 N·m of torque at 5,000 rpm. A five-speed ZF manual gearbox with a 40-percent limited-slip differential drove the rear wheels. Top speed was 265 km/h (165 mph). The suspension used double wishbones with adjustable coil springs and Bilstein gas dampers at all four corners.
By the time the M1 reached production, changes to Group 5 regulations meant the car could no longer be homologated for its original target class. Rather than abandon the motorsport programme, Neerpasch devised the Procar concept: a single-make series using racing-prepared M1s as a Formula One support race, with the top five qualifying Formula One drivers at each round required to compete alongside regular Procar entrants.
The series ran in 1979 and 1980, held on Formula One race weekends across Europe. The concept drew a remarkable grid at each round: established Grand Prix drivers — including Niki Lauda, Nelson Piquet, Mario Andretti, Jody Scheckter, Carlos Reutemann, and others — raced on equal mechanical terms with specialist Procar regulars. The cars themselves used a tuned version of the M88 engine producing more power than the road car, in a stiffer motorsport-specification chassis.
Niki Lauda won the 1979 Procar championship, accumulating points across the season. Nelson Piquet took the 1980 title. After BMW met the requirements for Group 4 homologation, the Procar series was discontinued, but the prepared M1s went on to be campaigned by various teams and privateer entrants in the World Championship for Makes and other national series.
The M1 was also entered at the 24 Hours of Le Mans from 1981 to 1986, competing in the Group B classification. In June 1979, an M1 Art Car with bodywork painted by Andy Warhol — driven by Hervé Poulain, Manfred Winkelhock, and Marcel Mignot — finished second in class and sixth overall in the 1979 Le Mans 24 Hours.
BMW France converted an M1 Procar to Group B rally specification for the 1982 and 1983 seasons. The Motul privateer team continued with the car in 1984, the campaign's most successful year, with Bernard Béguin winning back-to-back at the Rallye de La Baule and Rallye de Lorraine and claiming a second place overall at the Rallye d'Antibes in the European Rally Championship.
The Procar series is remembered as one of the few occasions when Formula One drivers were consistently placed in identical equipment alongside specialist competitors outside their usual championship, producing results that genuinely tested their all-round ability. The M1 itself — the first mid-engine BMW produced in volume — became a template for the M division's subsequent approach to road and motorsport cars, with its M88 engine carrying over into the E24 M635CSi, E28 M5, and South African 745i. Sports Car International named the M1 among the top sports cars of the 1970s in their 2004 rankings.