Cool Car of the week

“When things get so big, I don’t trust them at all. You want some control. You’ve got to keep it small”

Peter Gabriel, D.I.Y, 1977, the “Scratch” album

In 1968 the Commission Sportive Internationale (CSI or International Sport Commission), a branch of the Fédération Internationale du Sport Automobile (FIA or International Sports Car Federation), concluded that, once again, cars had become too fast and dangerous in the unlimited capacity Group 6 prototypes class.

This category had seen the titanic battles between Ford and Ferrari (the 7 L V8 Ford GT40 against the 4 L V12 Ferrari P2 and P3, featured in the “Ford vs Ferrari“ movie, btw if you are reading this post and don’t know what I’m talking about then you must log into Netflix, watch it and then come back. It is one hell of a good movie).

These monsters of a racecar were reaching speeds of more than 336 km/h (210 mph) in the Mulsanne straight at the 24 Hours of Le Mans. Considering that they still used steel disc brakes to stop these things, racing in those cars was not a particularly healthy activity.

So for the 1968 to 1971 seasons, the CSI limited engine displacement to 3 liters, and extended it later to 5 liters after receiving too few applications for the series. This change of rules tempted Porsche to return to the category and to Le Mans with a new design named 917 that turned the current Porsche 908 into obsolescence.

But Porsche could not get its act together, due to the car’s tendency to generate lift in the rear wheels. The ground effect and the downforce concepts were in an early stage in those days. 917s were fast but also were tail-happy in the corners. This, as you can imagine, is not the most adequate behavior for a car going at 200 km/h (125 mph) in 90 degrees curves.

In 1970, while doing more tests (Germans have a long-standing tendency to overengineering) at the Österreichring circuit in Austria, one of the Porsche engineers discovered that although the car was full of dead insects that had been caught in the 917’s trajectory, the car’s tail was clean. That meant that there was no airflow over the tail, hence no downforce on the rear wheels. Using advanced German engineering, (some aluminum sheets joined together with duct tape) they modified the tail to generate the required downforce and the short tail (Kurzcheck) 917 was created.

The development was complicated since many new technologies were employed in the car design. The engine was a 4,5 L flat 12 cylinder. Basically, two 911 flat sixes joined together. This air-cooled beast generated 520 hp. The 917 employed all kind of low weight exotic materials, like titanium and magnesium alloys. The body was made of a thin aluminum sheet. So thin, that the bodywork was constantly pressurized to detect any cracks in the welding. The car’s race weight was just 800 kg (1764 lb). In a test, the long tail (Langcheck) version reached 362 km/h (225 mph). Some significantly safe speed reduction, indeed.

Porsche won 9 of the 10 races of the 1970 season. After being an underdog at Le Mans for 20 years, they were the category leaders. That superiority continued in 1971 when the bodywork was rebuilt using magnesium alloys. In 1972 the FIA once again limited engine displacement to 3 liters, making the 917 unsuitable for Europe.

Porsche refocused and went to America to participate in the Can-Am series, where the 917 was equipped with a turbocharged flat 12 engine with 750 hp. Porsche dominated the 72 and 73 Can-Am series. The 1973 917/30 had a turbocharged 5.4 l flat 12 with 1100 hp.

Then came the oil crisis, a series of tragic accidents, and the fact that few teams were interested in racing against an invulnerable, overpowered, overengineered, and really expensive factory-backed group of teams racing 917s.

If you want to watch actual footage of these cars on Le Mans, you must find the 1971 movie obviously titled Le Mans, where one of the coolest guys ever, Steve McQueen, actually drives the cars and performs all the stunts, in front of the terrified eyes of the film producers. McQueen’s 917 was sold in an auction in 2009 for 14 million USD, a Porsche record. For those readers that were born later, now you know where does the name Lightning McQueen come from.