Rule changes for the World Championship of Makes eliminated the stunning Porsche 917 during the early 1970s allowing the factory to develop the car for the open-top CanAm championship in North America. Teams from McLaren, Lola and Chaparrals were attracted to the 200 mile Sprint races of the formula and the rule book permitted almost anything, including free engine displacement and the use of turbochargers.
Porsche used its new found skills with forced induction to attach two exhaust-driven turbochargers to the flat-twelve engine of the 917. The result had a displacement of 5.4 litres and produced between 1,100 bhp and 1,400 bhp making it one of the most powerful racing cars ever built.
The car, which weighs a mere 800kg, accelerates from a standstill to 100km/h (62mph) in just 2.4 seconds, by which time the driver has not even shifted into second gear! It reaches 200 km/h (124mph) in 5.6 secs, and passes the 300 km/h (186mph) mark in 11.3 secs.
The 917/30 went on to dominate in the 1973 CanAm with the top four places in the final points being taken back to Stuttgart and Porsche factory driver, Mark Donohue, setting a closed circuit record of 222 mph (355.85km/h) around the Talladega Oval, Alabama. A time that still ranks as one of the fastest race laps ever.
Only two examples of the 917/30 were built, and one of them has been the star of the Porsche Museum since 1975. It was completely restored in 2000, with the work not confined to the plastic body. Experts from Bosch optimised the engine’s throttle response by updating the control units. This also meant that the 24 spark plugs do not need to be changed so often. Purists may regret this departure from the original specification, but it does mean that the 917/30 can participate fully in renowned historic car events such as the Festival of Speed at Goodwood.
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