Bmw M12 13

As BMW M12/7, the engine design became one of the most successful in racing since the 1960s. It was used in the European Touring Car Championship and later in Formula 2. In Formula 2, it was expanded to two-litre and fitted with four-valve heads, producing over 300 hp (224 kW). In the Deutsche Rennsport Meisterschaft, a 1,400 cc variant was turbocharged by Paul Rosche according to FIA Group 5 rules. This variant produced well over 350 hp (261 kW) from the beginning. After development, power, driveability, and reliability improved, especially in the IMSA car, leading BMW to consider entering F1.

During the 1982 season, the Brabham team, then owned by Bernie Ecclestone, used both the older Cosworth DFV V8 engine and the turbocharged BMW M12 in selected races. Nelson Piquet recorded the first win for the engine in F1 at the 1982 Canadian Grand Prix. In 1983, Piquet won his second Formula One World Championship driving a Brabham BT52 powered exclusively by the M12. The M12 produced approximately 850 bhp (630 kW) in qualifying trim and 640 bhp (480 kW) for races that year. Piquet won the Brazilian, Italian, and European Grands Prix that year, winning the championship by two points ahead of Renault's Alain Prost. The inline-four M12 had lower frictional losses compared to its V6 Ferrari and Renault opposition, allowing Brabham's lead designer Gordon Murray to design the BT52 with smaller radiators. This resulted in better aerodynamic efficiency and straight-line speed.

1984 and 1985 were lean years for the M12. The engine was regarded as the most powerful in F1 at the time, producing approximately 1,100 hp (820 kW) in qualifying trim by 1985. However, its mechanical reliability and durability suffered, with engine blow-ups and turbo failures becoming common. High fuel consumption also plagued the four-cylinder BMW due to a maximum fuel limit of 220 litres per race. Piquet scored three wins during these years: the 1984 Canadian and Detroit races, and the 1985 French Grand Prix.

For 1986, the M12 was upgraded into the M12/13/1. This version was claimed to have produced a maximum output of 1,400 hp (1,044 kW) at 11,000 rpm. At the 1986 Italian Grand Prix at Monza, Gerhard Berger's BMW-powered Benetton B186 recorded the highest straight-line speed by a turbocharged Formula One car at 352.22 km/h (219 mph). Brabham tilted the upgraded engine sideways by 72° for use in the BT55, but this proved unsuccessful. Benetton were the leading BMW users in 1986, with Berger scoring his and the team's first win at the Mexican Grand Prix. BMW announced their withdrawal from F1 at the end of 1986 at the 1986 French Grand Prix.

Rebadged as Megatron, the BMW engines were used by the Arrows team for the 1987 and 1988 seasons, and by Ligier in 1987. By 1988, Arrows was one of only six teams still running turbocharged engines. The Megatron program ended after 1988 due to rule changes banning turbocharged engines from 1989. Eddie Cheever scored the engine's last podium finish with third place in the 1988 Italian Grand Prix at Monza. The M12's major shortcoming was its lack of throttle response due to turbo lag. Unlike twin-turbo V6 and V8 engines, the inline-4 BMW engine used a single turbocharger, resulting in approximately 2 seconds of turbo lag. This meant drivers often had to start accelerating through the apex of a corner. The power was described as coming on like a light switch, often inducing sudden oversteer.

World Championships: 1 (Nelson Piquet in a Brabham in 1983)

Wins: 9 (Piquet 7, Riccardo Patrese 1, Gerhard Berger 1)

Pole positions: 15 (Piquet 12, Teo Fabi 2, Patrese 1)

Fastest laps: 14 (Piquet 9, Patrese 2, Berger 2, Fabi 1)

This article is based solely on the supplied corpus. No external sources were consulted; claims that could not be substantiated against the corpus were omitted under the drop-the-claim rule.