Hall of Fame: Porsche 917 I

Many are the legends forged at Le Mans, but one stands out above the rest. The name of the winning driver often goes down in history, but this time it was the car, the incomparable Porsche 917.

By the middle of the last century, the Porsche team was carving out its place in the world of motorsport, moving forward with a firm and steady stride toward a fixed goal: winning the 24 Hours of Le Mans. In 1952, with the Porsche 356, it achieved victory in the 751–1100cc class.

As it gathered success, its hunger for the title grew ever greater, just as the competition did. Racing cars increasingly diverged from their road-going versions, engines produced ever more power, and levels of preparation became extremely high.

The French round was dominated by Lola, Ford and Ferrari, Porsche, with its small engines, could only match them on twisty circuits, but at Le Mans the long straights reign, where raw power is paramount.

With the aim of storming La Sarthe, Porsche designed a revolutionary concept of racing car, the Porsche 908. A flat-8 engine (opposed cylinders) was to propel a steel tubular chassis. On its first attempt they could not beat the powerful Ford GT40s, but they stood up to them. Despite having less power, behind the Ford GT40 “Gulf”, two Porsche 908s finished. They laid the foundations for success, and were getting ever closer to victory.

In 1969, with a change in regulations, the prototype category disappeared in favour of Group 4: limited-production sports cars (25 units) with engines of up to 5,000cc. This was a great challenge for the marque, which had never embarked on a project of such magnitude. They got to work, as they had to build the successor to the 908.

Ferdinand Piech knew that developing a new model would mean an extra cost, but he was convinced he could make it pay off by selling the cars to private teams at the end of the season. To this was added the support of Volkswagen, which would finance two-thirds of the project, on the sole condition that the Porsche 917 used an air-cooled engine, the hallmark of Volkswagen, which fitted that technology to all its models of the time.

Starting from the 908’s base, Porsche poured all its knowledge of exotic alloys into reducing the car’s weight to the absolute minimum. Magnesium, titanium and aluminium alloys were found everywhere, from the suspension wishbones to internal and external engine parts.
The goal was to have far less weight than the competition, without forgetting power. Starting from its predecessor’s flat-8, they added 4 cylinders, which raised displacement to 4,500cc, and the crankshaft was raised as much as possible to make the engine as compact as possible. The power figure was a respectable 580 horsepower. The bodywork was made of fibreglass with polyester resin, which greatly helped the lightness of the whole, reaching a weight of 800 kg, almost 200 kg less than the Ford.

But complications were not long in coming. First came homologation: under the regulations, the team had to build 25 road-going units, which could later be converted into racing cars. When the inspection arrived, Porsche had 3 assembled, 18 on the assembly line, and parts needed to assemble another 7. They said it would be no problem to assemble them, but it would be an unnecessary expense, as they would later have to be disassembled to be prepared for circuit racing. This did not please the CSI homologation commission, who told them they would return but expected to see all 25 Porsche 917s perfectly assembled.

They took them at their word and three months later returned to request homologation. The inspectors could not believe what they saw on arrival: 25 Porsche 917s awaited them outside the factory. On 1 April the Porsche 917 was homologated.

(As a curiosity, Ferrari had the 512 homologated a year later with only 18 units assembled)

TO BE CONTINUED…

Via | Ultimatecarpage