Let’s ignore four out of five segments here, and deal solely with one. The Porsche 956 is arguably the most influential racecar of the last 35 years. It was not only dominant, a 956 or 962 would win Le Mans every year from 1982 through 1987, it changed the shape of racecars. The 956 was the first sports prototype constructed around an aluminum monocoque chassis. All prior cars, including Porsche’s own 936/81, used tubular construction. This meant that any aerodynamic element added weight by design, as it had to be attached to the chassis rather than integrated with it. With the 956, Porsche created a chassis that was not just strong, but formed part of the car’s aerodynamic shape as an integral component of the ground-effect enhancing underbody.
Building to the Regulations
Group C regulations were exceptionally broad, especially compared to the relatively narrow constraints imposed on modern LMP1 teams. The regulations forced teams to adhere to the same standards as Formula 1 for frontal and side impacts, and imposed a dimensional box for all cars. The most serious constraint was on fuel consumption. As the Type 96C engine used in 1981’s Porsche 936/81 already met that regulation, the game was on to make a racing car which took full advantage of the rest of the regulations.
Aerodynamically, Porsche benchmarked the 917/30 Can-Am car. Thanks to its prodigious power the 917/30 could create an alarming amount of downforce without concern for drag. As the 956 would be less powerful, roughly 620 horsepower in race trim rather than 1000 horsepower as in the 917, Porsche needed to take care to keep the 956 from creating too much drag. The resulting car was a radical design, with venturi-type undertrays integrated into the aluminum chassis. To understand what a radical departure the aluminum chassis was, compare the structure of the 956 to its immediate predecessor, the 936. Where the 956 looks thoroughly modern, the tubular construction of the 936 resembles a Maserati Birdcage more than a modern sports prototype.
What made the 956 so successful
The monocoque didn’t just make the 956 strong, it made it aerodynamically efficient. The shape of the chassis could be tightly controlled to manage airflow. Even the rear suspension was designed to optimize airflow through the underbody venturi tunnels. All of this helped to suck the Porsche to the ground, while using relatively small wings to minimize drag. The slippery carbon-kevlar bodywork gave the 956 a drag coefficient of just 0.36cd; a shockingly low figure for a racing car with a high level of downforce. For reference, a modern F1 car has a drag coefficient of between 0.7cd and 1.1cd depending on setup.
This made for a highly competitive car. The 956 won the FIA World Sportscar Championship three times on the trot(1982-1984), Le Mans four times(1982-1985), set the Nurburgring lap record(set by Stefan Bellof in 1983, 6:11.13, a record which still stands), and it debuted Porsche’s first PDK transmission in the early 1980s.
Denouement For a Legend
Of course, the 956 wasn’t perfect. In 1983 it claimed just nine of the top ten spots at Le Mans. More seriously, the 956 steadily gained a reputation for being unsafe. While it fit the regulations concerning impact safety, incidents like Stefan Bellof’s accident at the 1985 1000km of Spa led to Porsche retiring the car and replacing it with the largely-similar 962.
The 962 continued on the same principles as its predecessor, but lengthened the wheelbase to move the driver’s feet aft of the front axle centerline. Following this change, the 956’s DNA would remain competitive into the 1990s. The final Le Mans win for the 962 came at the hands of a Dauer-Porsche 962C running in GT1 in 1994.
Even following its final triumphs in top-level series, the 962 lives on. The chassis remains popular with historic racers thanks to its relatively simple drivetrain and extremely high performance. A select few exist as road cars, converted by Koenig, Dauer and Schuppan. Long live the 956.
