Offenhauser

Offenhauser was a Formula One engine manufacturer from 1950 through 1960 for the Indianapolis 500.

The Offenhauser engine, familiarly known as the "Offy", was developed by Fred Offenhauser and his employer Harry Arminius Miller, after having spent some time maintaining and repairing a 1913 Peugeot Grand Prix car of the type which had won the Indianapolis 500. Impressed by the double overhead cam, four valve per cylinder design, which was a great leap forward at the time and would not be out of place even today, they designed an engine on similar principles. Originally sold as a marine engine, in 1930, a four-cylinder, 151 cubic inch (2.5 L) Miller engine installed in a race car set a new international speed record of 144.895 mph. Miller developed this engine into a twin overhead cam, four cylinder, four valve per cylinder 220 cubic inch (3.6 L) racing engine. When Miller went bankrupt in 1933, Offenhauser and another Miller employee, Leo Goossen, bought the shop and the rights to the engine, which they further developed into the Offenhauser engine.

One of the keys to the Offenhauser's success was, as might be expected, sheer power. Thus a 251.89 cubic inch (4128 cm³) twin-cam four-cylinder racing Offy with a 15:1 compression ratio and a 4.28 x 4.38 bore and stroke, could produce 420 horsepower (313 kW) at 6,600 rpm; 1.77 horsepower per cubic inch (81 kW/L). Other variants of the engine produced up to 3 horsepower per cubic inch (137 kW/L).

From 1934 through 1960 the Offenhauser engine dominated American open wheel racing, winning the Indianapolis 500 24 times. From 1950 through 1960, Offenhauser-powered cars won the Indy 500 and achieved all three podium positions, winning the pole position in 10 of the 11 years.