BMW M12/13

The M12/13 was developed by BMW's Motorsport division under the leadership of Paul Rosche, who had previously designed the successful BMW M10 engine. The turbocharged unit was based on the M10 block, but heavily modified to withstand the immense pressures of forced induction. It first appeared in 1982 in the Brabham BT50, driven by Nelson Piquet, who won the 1983 Canadian Grand Prix and clinched the 1983 Drivers' Championship with the engine. The engine's early reliability issues were gradually overcome, and by 1983 it was a race-winning package.

The M12/13 was renowned for its explosive power delivery, which made it both spectacular and challenging to drive. In race trim, it produced around 800–900 bhp, but for qualifying sessions, BMW turned up the boost to achieve an estimated 1,400 bhp, a figure that remains legendary. This power came at the cost of extreme turbo lag and fuel consumption, but it allowed Brabham and later Benetton to compete with the V6 turbo engines of Ferrari and Honda. The engine's peak power was achieved in 1986, when it was used by Benetton, and it was considered the most powerful engine of the turbo era.¹

After BMW officially withdrew from F1 at the end of 1986, the M12/13 continued to be used by Benetton in 1987 under the Megatron badge, with reduced development. The engine's final victory came at the 1986 Mexican Grand Prix with Gerhard Berger. The M12/13's legacy extends beyond F1: it was also used in the BMW GTP car that competed in IMSA, and its technology influenced later BMW turbo engines. The engine's power and sound made it a fan favorite, and it is often cited as a pinnacle of the turbo era.²

One lesser-known fact is that the M12/13 was originally designed as a naturally aspirated engine, and the turbocharging was an afterthought that proved remarkably successful. Another is that the engine's block was derived from the M10, which dated back to 1961, making it one of the oldest engine designs to win an F1 championship. The engine also set a record for the highest power output per litre in F1 history, exceeding 900 bhp per litre in qualifying trim. Additionally, the M12/13 was used in the BMW M1-based Group 5 car, but with a different turbo system, and it was also tested in a road car, the BMW M1, but never produced for the street.³

Turbo lag

The delay between throttle input and the turbocharger delivering boost, common in early turbo F1 engines.

Qualifying trim

A high-power engine setting used only for qualifying laps, with maximum boost and reduced reliability.

Megatron

A badge used by Benetton for the BMW M12/13 engine in 1987 after BMW's official withdrawal.