Porsche’s 959 supercar included a racing program with this spectacular 961 which placed 7th overall at the 24 Hours of Le Mans. It was one of the few cars to race the event in 4WD and the only 959 that raced on track.
As early as 1983, Porsche was modelling different shapes for the 961 race car for possible inclusion into Group B racing. Project manager Helmuth Bott decided on modifying a sole 959, chassis 959, chassis 10016, by adding larger 19 wheels and numerous aerodynamic upgrades. This would make the build relatively easy and promote the new Porsche flagship better than a more radical design.
Engine design was trusted to Valentin Schaffer who created the 961/70. He used the 959 flat-6 with 9.5 compression and 19 psi of boost to produce 680 bhp at 7500 rpm. For endurance purposed this was scaled back to 640 bhp. Each bank of cylinders had its own turbocharger and air-to-water intercooler. Water was fed from the cylinder-head cooling system and the block was exclusively air-cooled.1
Modifications to the body and under tray focused on aerodynamics. At the rear was large adjustable wing. The wider fender flares accommodated 11-inch wide wheels.
After the 1986 Paris-Dakar was over, Porsche focused their efforts on the 961 for Le Mans. All new body panels were formed out of resin. The brakes were the larger 956 rotors with standard 959 calipers.1
At Le Mans the 4WD Porsche was a sensation. It retained the complex torque-splitting PSK system with about 80% of the available power going to the locked rear differential. With Le Mans gearing a theoretical 213 mph was possible. The 961 was the only car entered in the experimental IMSA GTX category of racing. Drivers René Metge and Claude Ballot-Lena were responsible for all-white Porsche number 180. It was reliable enough to finish seventh overall.1
After Le Mans, Porsche flew the only 961 to America and contested the last round of the IMSA championship at Daytona. During the three hour race, the car suffered tire problems and finished 24th overall.
In 1987, the car made its second appearance at Le Mans in classic Rothman’s livery. Wider tires were fitted and power was up to 650 bhp. In the hands of Kees Nierop it suffered an accident and was rear-end was extensively burned. This was a the last race for the 961. Porsche retained and restored the 961 for their private collection.
Sources & Further Reading
1. Ludvigsen, Karl.Excellence Was Expected. Princeton Publishing Inc. Princeton, 1977.