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Porsche 917

The early years

The Porsche 917 took advantage of a loophole in the rules that was actually only supposed to allow the use more powerful engines from mostly British small volume manufacturers, like the Lola T70 with an American V8. According to Formula 1 rules for the Manufacture’s Championship, only three liter engine prototypes could be used, but these were of course, expensive and rare. In 1968 the international motor sports authorities (FIA) expanded the limits for engines from 3 to 5 liters and lowered the necessary volume for these production volume of the cars from 50 to 25 in the assumption, that no manufacturer could neither develop so many race cars, nor build and sell them.

For the Swabian-Germans who are known to be tight and who stopped their F1 involvement after their first successes because of cash problems in 1962, this was the starting flag for the construction the Porsche 917. Based on the 908, which had a 3 liter, eight cylinder and 258 kw (350 hp) engine, a bullish coupe with a 4.5 liter 12 cylinder engine was created. Contrary to popular opinion, it wasn’t a boxer motor but a 180 degree angled V12 which cranked out 427 (580 hp). The typical Porsche cooling system was used. "Air can't be lost along the way" was the justification Ferdinand Piëch used (although another reason was certainly a VW marketing one), for implementing VW's air cooling system. The grandson of the company founder and later VW boss was working at that time as a constructor at Porsche in Stuttgart Zuffenhausen and was a driving force behind the investment, which posed a big risk for the small producer at that time.

In spring 1969, the 917 surprised the car world at the Geneva Auto Show and, even more surprising were the needed 25 vehicles displayed on the grounds in Zuffenhausen (although they allegedly they had brakes drums made out of wood and other necessary improvisations.)

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Attention: All photographs are original black/white images from the original "Le Mans" photographer
(Lion André de Lourmel). Buy Steve McQueen photographs in the GPO Boutique

The long and short versions

On the back end of the 917 a movable flap was originally mounted to exert more pressure on the back tires. The movable spoiler was forbidden in 1969 by the FIA, after it was the cause of some serious accidnets in the F1. The longer back end, that should allow for a higher top speed in Le Mans, showed itself to be problematic in test drives because of the lack of wheel grip, so much so that the Porsche drivers refused to drive the 917 at its first race, the 1000 kilometer race at the Nürburgring. Porsche’s troubles didn’t end there, they also had to prove they’d sold the other produced cars to private customers and that they had made a profit. Britsh drivers David Piper and Frank Gardner were eventually hired to drive the 917 to seventh place, the factory drivers preferred the more successful and agile 908.

At Le Mans the 917s went into the race as the favorites, although the first round ended deadly for one of the drivers John Woolfe. The other 917 drove for longer time but ultimately, due to gear problems, couldn’t fight for the overall title which was won by Jacky Ickx and his 5 liter Ford GTO in a close race with Hans Herrmann and his 3 liter 908. In the same year Jo Siffert and Kurt Ahrens celebrated their 1000 their first overall victory for the 917, albeit with the short ended coupe version, at the 1000. Ferrari joined in on the manufacturing race as it sold Fiat and invested in the production of 25 expensive super race cars and then introduced the Ferrari 512 giving Porsche a more powerful opponent thanks to the water cooling and the four valve technology. The weight was, however, higher because a steel frame was used. The Swabians by participating in smaller classes had a lot of experience in building light frames by using new materials and manufacturing techniques, like using air pressure for cracking or testing aluminum frames.

The first overall victory for Porsche

For the racing season of 1970 the team work with John Wyer’s Gulf team resulted in a reworked back end. Two versions were created, a reworked longer version and a wedge-formed shorter version that had improved handling, the so called 917K.

Even with the less suitable version, which still hadn't been equipped with the new more powerful 4.9 liter engine, Porsche registered its greatest victory up to that point at the 24 hours of Le Mans. In the red and white colors from Porsche Salzburg Hans Herrmann and Richard Attwood fought their way from 23rd to first. The 917 long version from Martini painted blue and yellow with a psychedelic design took second behind the driving of Gérard Larrouse and Willy Kauhsen. A sweep at the Sarthe for Porsche!

 

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1971 was also a stellar year for the 917. The 917 motor produced 442 kw (600 hp) from 4.9 liters of cubic capacity. A later face-lifted version with Nikasil coated cylinders and the maximum 4.99 liter capacity was able to crank out 630 hp. It also sported improved aerodynamics were improved, especially up front. These were necessary because Ferrari had already proved to be faster although it was still unreliable and cursed by bad luck as evidenced by a massive crash, which eliminated the whole team in 1970. In comparison with the 512S, the 512M showed some strong similarities with the 917K.

In the course of that season, Ferrari immediately tried the 3 liter 312 PB without prior plant testing. The American Penske team used a powerful Sunoco blue painted 512M equipped with a fast-filling tank system that made the Porsche team shake their heads. Alfa Romeo collected with the 33/3 wins at Brand Hatch and at Targa Florio. At Le Mans, Porsche repeated its success of the previous year, but the long version came up short again, although it reached speeds of 396 km/h in training rounds because the white Martini Porsche 917K from Helmut Marko and Gijs van Lennep number 22 wasn’t to be stopped. The winning car was equipped with a frame made out of magnesium pipes that proved to be a few kilograms lighter than aluminum, but a lot more dangerous in accidents due to their flammability.

The Little Pink Pig

In 1971 at Le Mans more than half of the cars at the pole were Porsches. The most photographed of these cars was definitely “the pig”. The 917/20, a mix between the short and long versions with reworked aerodynamics and a wider body, was so nicknamed because of the pink paint job and butcher-style cuts it had. In the race itself, the car was eliminated, although it had a great start position because of its success in the preliminary race. By the end of the 1971 season the special regulations for the 5 liter race cars expired and the 917, the Ferrari 512, the Lola t70, the Ford GT40 etc., were not allowed to race in the ‘72 season. In the Inter Series as well as in the CanAm, there was still a place for these bad boys to play. Production of the 3 liter Porsche 908 was given up by the company and it was sold. Steve McQueen subsequently used these monuments of racing history in his film Le Mans. The subdued star of the film was the open Porsche 908/2 that competed in the race and despite the mounted cameras and frequent stops finished in the top ten.

The 917 in North America

In the popular Canadian-American race series CanAm, Porsche found a new playground for the 917. With a 917 coupe, a derivative from the Spyder version, Jo Siffert finished in fourth place in the overall standings in 1969. The motor proved to be too weak in comparison with the V8 monsters from Chevrolet which had up to 9 liter (800 hp) engines. In Zuffenhausen, Ferdinand Piëch, following in the footsteps of his grandfather at Auto-Union, pushed for a 16 cylinder variant with approx. 552 kw (750 hp).

The new use of compressors developed by the Porsche founder, which had already been used at Mercedes-Benz and Auto-Union for decades, unleashed more power out of the same compact motor block: the new Spyder had a 5 liter 12 cylinder engine and two turbochargers at its disposal. The performance surpassed the expected maximum of a 16 cylinder inductor. The American Penske team agreed on a contract for the Porsche 917/10, in which driver and engineer Mark Donohue had considerable stake in. The delayed response time, that until then had only made it sensible to use in full gas oval races like Indy, were improved for to make them suitable for other kinds of race. The resulting 850 to 1000 hp (736 kw in training) were taken advantage of by Donohue and his modified driving style. The big spoiler and the specially shoveled front end maximized output. This, however, increased the drag coefficient and so that the top speed was “only” 343 km/h.

In 1972 George Follmer became the CanAm champion after Donohue had to pull out with injuries. The series leader up to this point had been McLaren, who had given the CanAm the nickname “The Bruce and Denny Show”, concentrated on the Formula One after the death of its founder.

In Jahr 1972 wird George Follmer CanAm-Meister, nachdem Donohue verletzungbedingt ausfiel. Die bisherigen Seriensieger von McLaren, die der CanAm den Spitznamen "Bruce und Denny Show" eingebracht hatten, konzentrierten sich nach dem Tod des Gründers 1970 allerdings zunehmend auf die Formel 1.

From O to 300 in 11.3 seconds

The Penske team used the revamped Porsche 917/30 in 1973. The motor with 5400cm³ produced an unbelievable 810kw (1100 hp) and 1140 kw (1500 hp) for short periods during testing. Thanks to this output the 800 kilogram car was able to go from 0 to 100 km/h in 2.1 seconds, 0 to 200 in 5.3 seconds, and 0 to 300 in 11.3 seconds. The car could reach a top speed of over 400 km/h thanks to a wider wheel base and a stable suspension system. The consumption was between 76 and 97 liters for every 100 kilometers, which made a 400 liter tank a must. In 1973 Porsche won the CanAm Championship again and even more decisively than the year before with Mark Donohue at the wheel.

In 1974 the career of the 917 turbo in North America was bridled because of rule changes. Under pressure form the oil crisis and from horrible fiery accidents like Roger Williamson’s in Zandvoort in 1973 the fuel limits were decreased. With these measures were aimed at breaking Porsche’s one-sided dominance. The 917/30 was only used by Penske in one race. Although only a few 917/10s were still found in the hands of customers in North America, in Europe they were used in the Inter Series, both the Turbo and the Inductor (with a rounded front) version.

Racing Versions

The Porsche 917 was produced and used from 1968 to 1971 in the following versions:

917 Long versions (Coupe)

  •  4494 cm³ 12 cylinder induction motor, 427 kW/580 hp
  •  4907 cm³ 12 cylinder induction motor, 442 kW/600 hp
  •  Top speed approx. 380 km/h
  •  Rear-wheel drive
  •  Permanent rear spoiler

917 Short version (Coupe)

  •  4494 cm³ 12 cylinder induction motor, 427 kW/580 hp
  •  Top speed approx. 340 km/h
  •  4907 cm³ 12 cylinder induction motor, 442 kW/600 hp
  •  Top speed approx. 360 km/h
  •  Rear-wheel drive
  •  Wedged-back, vertical rear fins (1971)

917/20 (Coupé)

  •  4907 cm³ 12 cylinder induction motor, 442 kW/600 hp
  •  HTop speed approx. 360 km/h
  •  Rear-wheel drive
  •  Reworked body
  •  Permanent rear spoiler

source: http://www.grandprix-originals.com/english/index.php?action=porsche917