Porsche 917 Racing
Porsche first revealed the 917 to the press at the 1969 Geneva Motorshow. This was followed by an intense CSI homologation inspection, demanding that all the cars needed to be complete before the car could race. Remarkably, Porsche produced eight more cars in three weeks to complete the necessary 25 cars. On April 1st, 1969 the 917 was homologated just in time for Le Mans.
During initial tests, the 917 was found to be particularly unstable and many driver’s began to have doubts about its design. At the 1000km of Spa, a long tail 908 was chosen in favor over the 917. Before the 917 hit Le Mans, it debuted at the 1969 Nürburgring 1000km and in the hands of David Piper and Frank Gardner. No factory drivers would chose the 917 and instead piloted 908 Spyders to a 1-2-3-4-5 victory. The 917 trailed in eighth place.
Leading up to Le Mans, many drivers were cautious about the 917. 917s set the fastest lap in practice and looked to have all the right ingredients to win. Three cars were entered in the race, two factory entries and one loaned to John Woolfe Racing. Unfortunately, John Woolfe suffered a fatal crash on the very first lap which was later attributed to his seat belt and lack of experience. The remaining 917 team cars led for around 300 laps before both dropped out with clutch bell housing problems.
For the 1970 season, 917s were sold to Martini Racing, JWA Gulf Racing and Porsche Salzburg—all private teams that would be supported by the factory. Under the direction of John Wyer, the engineers at JWA tackled the handling problems first discovered in testing. Wyer’s engineer, John Horsmann, came up with a solution to hack off the rear section of the bodywork and replace it with a new aluminum section. This greatly improved stability. Porsche later made revised tail sections for most of the cars and called the cars Kurzheck or 917K. Surprisingly, another low-drag version was designed by Robert Choulet. Known as the Langheck, it was intended to achieve big top speeds down Mulsane Straight.
Porsche also experimented with the boring out the engine to a new 4.9 liter configuration which produced 20 additional horsepower. Later, it was found that these engines put too much strain on the gearbox.
For the 1970 season, Porsche faced Ferrari’s own 512S which was underpowered and overweight by comparison. Even though Ferrari brought out eleven cars, Porsche success through quazi-works teams was practically guaranteed. Only an hour and half into the race, the Ferraris were trailing. Through heavy rain and storms two 917s finished ahead of a 3.0-liter 908. Hans Herrmann and Richard Attwood drove their Salzburg red and white 917K to Porsche’s first overall victory at LeMans.
For the 1971 Season, Porsche faced some new competition including Roger Penske’s 600 bhp 512S and the Alfa Romeo T33/3. To prepare, Porsche revised both the short and long versions of the 917. Both had slight body changes that included vertical fins on the K and LH was changed to reach speeds up to 248 mph.
One of the most radical developments for 1971 was a single magnesium frame that was fitted to chassis 053 and raced by JWA/Martini. Painted white, this car placed first overall at Le Mans. It was driven by Helmut Marko and Gijs van Lennep to set an overall distance record. After winning LeMans twice and accomplishing their goals, Porsche had become a power in sports car racing over a three year period. The CSI abandoned Group 4 leaving the 917s to contest other series. Later versions of the 917 were prepared for CanAm and featured turbocharged engines that could produce in excess of 1100 bhp.