1973 Porsche 917/10 and 917/30: Turbochargers
Turbochargers — exhaust gas driven superchargers — were proven elements in aircraft engines during World War II, and had been used with frustratingly mixed results on such production cars as the Chevrolet Corvair by the early 1960s. It was the development of electronic ignition controls and advanced fuel injection systems that finally made turbos effective in racing and on the street.
The car that got the mix right first was the 1972 Porsche 917/10 that competed in the North American Can-Am Challenge prototype racing series. Using Bosch mechanical fuel injection and two turbochargers, the 917/10's 4.5-liter flat-12 could produce up to 1,100-horsepower in qualifying trim. Its successor, the longer wheelbase 917/30 used a 5.4-liter version of the flat-12 that made over 1,500-horsepower during qualifying — the most powerful sports car ever raced.
During the 1973 Can Am season, 917/10s would win the first of the eight races, while Mark Donohue driving for Penske would take the other six driving a 917/30. "We’re far from having too much horsepower,” Donohue once said. "My definition of too much horsepower is when all four wheels are spinning in every gear." It was a performance so overwhelming it essentially killed the Can-Am.
But Porsche took the turbocharging lessons it had learned with these beasts and applied them to the six-cylinder 911 in both racing and street trim. The Porsche 911 Turbo became a legend, and turbos today are used on everything from some Ford Fiestas and F-150 pickups to the new Ferrari 488.