The Alfa Romeo 158/159, also known as the Alfetta or the small Alfa in Italy, is one of the most successful racing cars ever built. These chic cars made racing history with their 47 victories at 54 Grand Prix starts. The single-seater Voiturette, commissioned by Enzo Ferrari and designed by Gioacchino Colombo, was built in 1937 and had an in-line engine with 1479 cc and a single-stage Roots compressor; during the first tests, the machine already delivered a remarkable 190 hp at 6500 rpm.
After a modification in 1938 the small engine produced 220 hp, further modifications increased the power over the years to 350 hp at 8500 rpm. The eight originally stood for 8 cylinders in the 15 Series. Until the “Tipo 159” replaced the Voiturette, the race car received two plain bearings for the transverse leaf suspension, among other things, and the design engineers lowered the centre of gravity. Thus, the 158 reached an agility that made him one of the biggest competitors for the giants of his time.
As Tipo 159, Alfa Romeo used the modified 158cc 1951 in Formula 1, after which the Italian withdrew from racing for the time being. The 159 continued to pull its 310 km/h out of the small engine, but Alfa Romeo replaced the single-stage compressor with a two-stage compressor and stored the crankshaft nine times. In addition, the racing car was fitted with a de Dion rear axle, a driven rigid axle with separately installed differential. The 159 was driven by a fuel mixture of 98.5 percent methanol, 0.5 percent water and one percent castor oil. The last version of the racing car had 420 hp at 9600 rpm with a power transmission of 382 Nm.