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The BMW M12/13 turbo 1500 cc 4-cylinder turbocharged Formula One engine, based on the standard BMW M10 engine introduced in 1961, powered the F1 cars of Brabham, Arrows and Benetton and won the world championship in 1983.
As BMW M12, the engine design since the 1960s became one of the most successful engines in racing. Starting with the European Touring Car Championship, it was also used in Formula 2, expanded to two litre and fitted with four-valve heads, producing over 300 hp (224 kW). In the Deutsche Rennsport Meisterschaft, a 1400 cc variant (with a 1.4 handicap factor equal to 2000cc) was turbocharged by Paul Rosche according to FIA Group 5 rules. At well over 350 hp (261 kW) from the beginning, it rendered the normally aspirated engines in the two liter category useless. After some development, power, driveability and reliability improved, especially in the IMSA car, and BMW began to think about entering F1, where a handicap factor of 2.0 required 1500 cc engines.
In 1983, Brazilian driver Nelson Piquet won the Formula One World Championship driving a Brabham BT52 powered by the turbocharged BMW M12 engine, which in 1983 was producing approximately 850 bhp (630 kW) in qualifying trim and 640 bhp (480 kW) for the races. Piquet, who won the Brazilian, Italian and European Grands Prix in 1983, won the championship by just two points in front of Renaults Alain Prost (Renault had pioneered turbocharging in F1 in 1977). Piquet's win was the first time a car powered by a turbocharged engine had won the World Championship.
In the years 1986 and 1987, the version M12/13/1 was tilted sideways by 72° for use in the extremely low Brabham BT55 (1986) and more conventional Brabham BT56 (1987). The design was not successful, probably due to cooling issues in the tight compartment. The 1986 engine was said to produce about 1,400 hp (1,044 kW) in qualifying, that being the most powerful figure of all the turbo-charged engines in Formula One (though it should also be noted that at the time there was no way of accurately measuring horsepower over 1,000 and figures are what were generally accepted from the engineers calculations with 0.1 Bar of turbo boost rated to be worth approximately 20 hp (15 kW)). During 1986 however it was the Benetton team using the conventional upright BMW M12 who would be the leading BMW runner in Formula One, with Gerhard Berger scoring his and the teams first (and the BMW engines last) win by winning the 1986 Mexican Grand Prix. Benetton would not continue with the BMW engines in 1987, instead they became the defacto factory Ford team using their Ford TEC turbo in the BMW's place.
As BMW announced to pull out officially at the end of 1986 (though they would continue to supply Brabham with their tilted engine for 1987), Arrows team boss Jackie Oliver brokered a deal with support from the teams primary sponsor USF&G to continue the use of the upright BMW engines under the name of its subsidiary Megatron, Inc., founded by long-time F1 aficionado John J. Schmidt, who coined the phrase "Horse racing may have been the sport of kings, but auto racing is the sport of corporations". The engines were serviced by Arrows long time engine guru Heini Mader from Switzerland, a former mechanic of Jo Siffert.
Rebadged as Megatron, the BMW engines were used by the Arrows team for the 1987 and 1988 seasons, as well as Ligier for 1987 only. In the final season for the turbos, Arrows were one of only six teams still running turbocharged engines and the only team to still use the old BMW engines. During the 1988 season the Megatron engines were the oldest turbos still in use in Formula One dating back to 1982 (Ferrari, who had been using turbos since 1981, had introduced a completely new engine from 1987).
The Megatron programme ended as a result of a change of Formula One engine rules which banned turbocharged engines at the end of 1988, with American driver Eddie Cheever achieving the old BMW engines last podium finish with third place in the 1988 Italian Grand Prix at Monza. The race was also significant as it was the first time Heini Mader had solved the problem caused by the FIA's pop-off valve which limited turbo power to 4.0 Bar in 1987 and 2.5 Bar in 1988. By moving the valve closer to the engine, the problem of the turbo not delivering enough boost had been solved and the Arrows A10B's were among the fastest on the long Monza straights, faster even than the all-conquering McLaren-Hondas which effectively incorporated Gordon Murray's lowline Brabham design as well as featuring a more powerful V6 engine.
The Formula 2 M12 was also the basis for the highly successful BMW M3 Group A touring car. The 2.3 liter engine powered the M3 (which really was a middle class car compared to its rivals such as the Ford Sierra RS500) to the 1987 World Touring Car Championship, the 1987 and 1988 European Touring Car Championship's, the 1987 Australian Touring Car Championship, the 1988 British Touring Car Championship, and the 1987 and 1989-93 Italian Touring Car Championships.
- "BMW Turbo F1 Engine". Gurneyflap.com. Retrieved 2010-09-13.
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