The North American Can-Am series, a tournament series with racing stages in Canada and the USA. In the FIA Group 7 racing events with no regulation on engine displacement of very fewer restrictions at all, it was the most rebellious FIA class ever.
The Porsche racing department was responsible for the assembly of a single Porsche 917 Spyder variant designated as the Porsche 917 P+A. Its body style resembled the body shape of the fourth-generation Porsche 908/3 Spyder which was yet to be developed.
P+A designation was a reference to the Porsche and Audi dealer’s relationship in the United States. The Porsche 917 P+A was powered with a 4.5-liter Type 912/00 engine derived from the Porsche 917. The 560hp maximum power delivery wasn’t powerful enough to carry its 1710 pound overall ready to race weight while carrying 47.6 gallons of fuel.
Porsche team driver, Jo Siffert finished third in his debut event at Bridgehampton, New York.
This was his best finish for all seasons.
It was evident that the car needed more power.
Porsche 917K the Rennwagen Wunder
In 1970, the FIA introduced its own version of the Can-Am series in Europe. The Interserie also featured fewer restrictions following the liberal attitude of the Can-Am Series.
Porsche ran five Porsche 917 K cars at Watkins Glen for the North American Cam-Am Series. Jo Stiffert finished second the day before the FIA WCM event, and since the WCM event was more important to the factory, Porsche decided to ignore the rest of the Can-Am season.
Ferrari and Porsche dominating the FIA racing events using the full advantage of the 5.0-liter engine displacement restriction for sports cars. Ferrari 512 and Porsche 917 led every major FIA event in Europe.
FIA decided to put an end to this war between Porsche and Ferrari for absolute dominance by restricting the maximum engine displacement to 3.0-liter for the 1972 racing season. The cars were supposed to retain a minimum weight of 1433 pounds as well.
Porsche concluded that it wasn’t possible to win the FIA events, then the Can-Am series began as a manufacturer’s racing event, with WCM championships in 1970 and 1971, Porsche refocused its attention to North America for the 1972 season.
Hans Mezger and his engineers increased the displacement of the engine Type 912/10 from 4.9-liter to 5.4-liter. The new 5.4-liter V12 was designated as the Type 912/12. Power output was 660hp as a result. However, this power output wasn’t enough to give a proper competition against the 8.0-liter V12 powered McLaren packing 750hp.
With McLaren dominating the Can-Am events, Porsche engineers decided to do something that they did a few years ago.
How they created the 4.5-liter V12 was by merging a 3.0-liter V8 with another half of a V8, thus resulting in a 4.5-liter V12. Engineer Valentin Schaffer just mated another half of an engine to the mix to create a V16 engine. The power output was now 760hp. But, the 6543cc V16 engine weighed too much because it was practically two V8 engines combined to perform as one powerplant.
Ferdinand Piech asked Valentin Schaffer to experiment on turbocharging which proved to be challenging and uncharted territory for Porsche.
Porsche engineers had to configure pressure levels, and plumbing along with wastegates to get rid of the extra boost that may result in the engine explosion. Eventually, Valentin Schaffer got the system in working order. The new twin-turbocharged 4.5-liter V12 was now designated as the Type 912/50. The maximum power output was now measured at 850hp.
A 4.9-liter V12 engine with twin-turbocharging delivered an astonishing 1000hp.
Increased power also meant a new body with better aerodynamic efficiency was needed to keep the car grounded without lifting off.
Helmut Flegi, the body engineer, with his experience regarding the wind tunnels and aerodynamics, carried on extensive wind tunnel tests to create a functional wedge style body shape with a protruding nose front fascia and an extended rear wing.
This new car had bold looks and with the experience of Porsche competition director John Wyer and the backing of his Gulf Oil Sponsorship, Porsche decided that they needed one of the best drivers to pilot their car. Former Porsche team driver Roger Penske was chosen with hi backed by the Liggett and Myers Tobacco.
Porsche 917/10 was unveiled for the 1972 racing season and the trio of Porsche driver, Roger Penske, George Follmer, and Mark Donohue went on to dominate the events. These victories gave Porsche the Championship title. Drivers’ Championship titles were won by Penske and Follmer.
For the 1973 racing season, Valentin Schaffer came up with an even more capable engine design.
The new Type 912/50 was a 5.4-liter V12 with twin-turbocharging delivered more than 1000 horsepower and according to Schaffer, it could deliver up to 1200hp with a 1.3-atmosphere boost.
Helmut Flegi went on to lengthen the Porsche 917/10’s 2300 mm wheelbase up to 2500 mm, to make the car more stable. The whole body was tested in a wind tunnel again to make it more aerodynamically efficient. Regular tests on the wind tunnel as well as on the Weissach test track resulted in a dozen of body modifications and revisions.
The new engine-equipped car was designated as Porsche 917/30.
The Porsche 917/30 was an excellent car, and it was an all-time great for Porsche due to its superb handling and performance. Roger Penske and Mark Donahue went on to win the event after the other.
Mark Donahue won six of the eight races of the 1973 season, and he may have won the other two if it wasn’t for the middle eastern political crisis that straddled the seventh race.
The war between Egypt and Israel and the role played by the USA and the Soviet Union during the war until a ceasefire agreement was signed on 25th October, resulted in strong anti-western sentiments among the Arabic countries.
OPEC (Organization of Arab Petroleum Exporting Countries) decided to decrease oil production and shipments by five percent per month until specific political and territorial demands were met. OPEC also raised the price of crude oil by almost 80%, from $2.90 to $5.11 per barrel.
This resulted in increased prices of raw materials and an eventual economic downturn. To cope with limited oil supply, Western Germany decided to take active measures to limit the use of oil from November 1973.
1974 Can-Am season ended after five races and did not resume until the 1977 racing season due to increased cost and the economic impact created by the OPEC decision.
The European version of the Can-Am, the Interserie continued despite the political and economic situation. Porsche team driver Herbert Muller won the 1973, 1974, and 1975 World Championships behind the wheel of a Porsche 917/30.
Without a doubt, Porsche 917/10 and Porsche 917/30 are among the most successful racing cars of all time. Three consecutive World Championship winning Porsche 917/30 was exactly what Porsche needed at the time.
Due to the increasing economic difficulties, Porsche withdrew from racing for a while