Porsche 917: Twenty-Five Cars, One Very Nervous Inspection
When the Rulebook Asked Porsche to Prove It Was Serious
Ferdinand Piëch wanted Porsche to win Le Mans. Not its class. Not a respectable finish behind somebody with a larger engine and a happier accountant. He wanted the whole thing.
Then the 1969 rules handed Porsche an opening big enough to drive a five-liter sports car through. A Group 4 car could compete if the manufacturer could prove it had built 25 examples.
The requirement was supposed to discourage somebody from building one outrageous prototype, calling it a production car and turning up with enough machinery to ruin everybody else’s weekend.
Piëch found another interpretation.
Build the outrageous prototype 25 times.
Twenty-Five Is a Lot of Prototype
Hans Mezger and Porsche’s engineering group were already developing what became the 917: a tiny, lightweight race car wrapped around an entirely new flat-twelve engine. Building one would have been serious work. Porsche now needed a small parking lot full of them.
And the homologation people wanted cars, not twenty-five promising collections of tubing, engines and body panels accompanied by a note saying the rest would be along shortly. The examples had to exist when the inspector arrived.
Hermann Burst organized construction of the homologation batch while engineers, mechanics, fabricators and body specialists tried to turn prototype-race-car building into something resembling mass production.
“Mass production” was doing some heavy lifting there.
No dealers were waiting for truckloads of identical 917s. Porsche was building twenty-five very expensive race cars at once because somebody with a clipboard intended to count them.
Nothing improves factory productivity quite like an inspection date that can kill the entire racing program.
Bring a Rope. Make It Look Organized.
On April 21, 1969, Porsche lined all 25 cars outside Plant 1 in Zuffenhausen for the FIA inspection. Hermann Burst later remembered that the crew even used a rope to get the line straight.
That was smart. If you’re asking officials to believe you have just produced twenty-five five-liter racing prototypes, presentation is no time to get casual.
From across the yard, the argument was magnificent. One Porsche 917. Another Porsche 917. Then another, and another, until the rulebook ran out of fingers and had to admit there were twenty-five.
The regulation had asked Porsche to build the cars.
Porsche had built the cars.
There was only a slight disagreement over what “finished” ought to mean.
Please Point at Number 12
Burst later described all 25 as ready to drive, then corrected that description. Ready to roll was closer.
The factory had been assembling the cars so quickly that there were not enough suspension springs available for every chassis. Some of the 917s standing proudly in that perfect line were being held up with pieces of water pipe.
They looked finished.
They rolled.
Driving one would have introduced several additional questions.
Then the inspector decided to choose a car and see whether Porsche’s impressive collection could do more than decorate the pavement.
He picked number 12.
Fuel was poured into the intake funnels, the flat-twelve fired, and number 12 drove out toward the factory gates and returned under its own power. The inspector had his demonstration.
Porsche had its luck.
Number 12 happened to be one of the cars equipped with actual suspension springs.
There were twenty-four other numbers available. Some of them would have made the afternoon considerably more interesting.
Close Enough for Homologation
The 917 was approved. The inspectors had seen the required twenty-five cars, and Porsche had demonstrated that the one they selected could start, move and return without leaving its suspension plumbing in the parking lot.
That is what makes the story better than some cheap inspection dodge. Porsche did not run one car through twenty-five times. It really built the entire batch. The company simply reached inspection day with some examples more enthusiastic about being race cars than others.
The rule had been designed to make an outrageous one-off prototype economically unattractive.
Porsche responded by making the outrageous one-off prototype economically unattractive twenty-five times.
Then the Ridiculous Idea Won Le Mans
Homologation did not instantly turn the 917 into the car Piëch wanted. The early version was difficult to drive and initially unreliable. Porsche had won the argument with the rulebook; it still had some arguing left to do with the race car.
That part eventually got sorted out too. The 917 won Le Mans in 1970 and again in 1971.
So the regulation intended to keep wild five-liter prototypes from becoming somebody’s private science project produced one of racing’s most famous machines instead.
The FIA asked for twenty-five cars, Piëch built twenty-five, and Burst lined them up with a rope. Some had suspension springs. Some had plumbing.
The inspector chose number 12.
Sometimes the difference between a brilliant racing program and a very expensive explanation is one fellow pointing at the right car.