The first supercharged car to win a Grand Prix was the 1923 Fiat 805-405. Other early adopters included the 1924 Alfa Romeo P2, the 1924 Sunbeam Grand Prix car, the 1925 Delage, and the 1926 Bugatti Type 35C. These cars demonstrated that a mechanically driven compressor could dramatically increase the power output achievable from a given engine displacement, making supercharging standard practice in serious Grand Prix machinery through the late 1920s and into the 1930s.
The world's first series-produced supercharged cars had appeared from Mercedes-Benz in 1923, marketed as Kompressor models, establishing the German manufacturer's early familiarity with the technology.
The AIACR's 750 kg formula, introduced in 1934, set a maximum car weight without imposing any limit on engine capacity. Regulators believed the weight constraint would naturally restrict engine size to around 2.5 litres, but the German manufacturers — Mercedes-Benz and Auto Union — demonstrated that metallurgical advances and lightweight construction could accommodate supercharged engines of vastly greater displacement within the weight allowance.
Auto Union's cars, designed by Ferdinand Porsche, used a supercharged V16 engine that began at 4,360 cc in 1934 and grew to six litres by 1936, producing 520 bhp (388 kW). The engine used a Roots-type blower and was designed to provide optimum torque at low engine speeds rather than peak power at high revs. Mercedes-Benz responded with a series of supercharged inline-eight engines, culminating in the M125 of 1937, which displaced 5,662 cc and produced between 560 and 595 horsepower at 5,800 rpm. The M125 used a Roots-type supercharger and exotic fuel blends including methyl alcohol, benzene, and ethyl alcohol — mixtures tailored to allow higher boost pressures without detonation.
These power outputs made the 750 kg formula cars the fastest road racing cars of their time, reaching race speeds above 300 km/h (190 mph) on fast circuits. The fumes from the exotic fuel mixtures were so potent that spectators and mechanics near the pits complained of headaches, nausea, and respiratory problems.
Prewar Grand Prix superchargers were predominantly of the Roots-type positive-displacement design, which delivers a near-constant volume of air per revolution regardless of engine speed. This provided strong low-end torque but limited efficiency at high boost levels compared to centrifugal designs. Mercedes-Benz experimented with a suction carburettor supercharger system during the 1937 season, introducing it at the Eifelrennen and subsequently fitting it to all W125s after its advantages were demonstrated.
The development of high-octane fuel, pioneered in the United States during the 1930s, was critically linked to supercharger performance. Higher-octane fuels resisted detonation under greater boost pressures, enabling manufacturers to extract more power from their engines. The custom fuel blends used by the German teams — formulated in partnership with chemical companies — were a direct response to this relationship between octane rating and available boost.
The catastrophic speeds generated under the 750 kg formula, and the frequency of serious accidents, prompted the AIACR to introduce new regulations for 1938 that limited supercharged engines to 3,000 cc and unsupercharged engines to 4,500 cc, while also specifying a minimum car weight. This directly forced the retirement of the six-litre Auto Union V16 and the 5.7-litre Mercedes M125. Both manufacturers developed new, smaller supercharged engines for the revised formula — Mercedes with the W154's 3-litre V12, and Auto Union with the Type D's 3-litre V12 — which continued to produce substantial power, with the Auto Union V12 developing close to 550 horsepower.
The prewar supercharger era established the technical and regulatory logic that has shaped motor racing ever since. The pattern of manufacturers finding unintended performance headroom within ostensibly restrictive rules — and regulators responding with tighter constraints — repeated itself through the turbocharger era of the 1980s and beyond. The Silver Arrows' supercharged engines also demonstrated the potential of forced induction for road cars; Mercedes-Benz's Kompressor production models of the early 2000s were a direct descendant of that lineage. The power figures achieved in 1937, exceeding 600 horsepower from a road racing engine, were not surpassed in Grand Prix racing until the turbocharged engines of the early 1980s.