Page 1 of 2 Next >> With the all-new Group C sports car regulations due to be introduced the following year, the 1981 season turned out to be an interim year. The leash on the Group 6 prototypes was already loosened to allow manufacturers to run new engines and/or cars a year early. Porsche used this opportunity to test the engine for the upcoming 956 Group C car in anger during the 24 Hours of Le Mans. One of their privateers, Kremer Racing used the same loophole for Le Mans, not to look ahead but to bring an old legend out of retirement; the Porsche 917.
The Group 6 regulations of 1972, which stipulated a three-litre displacement limit, had rendered the 917 obsolete from World Championship event. In the following decade, Kremer Racing actually restored one of the original 917s for a customer, so they had intimate knowledge of the twelve-cylinder engined racer. The two Kremer brothers reckoned there was life left in the design, especially if it was updated to suit the latest tyre technology. So, instead of bringing one of the existing cars out of retirement, Kremer Racing decided to build a brand new 917, with support from Porsche.
One of the main reasons to start from scratch was that Kremer reckoned the original all-aluminium spaceframe chassis would no longer be up to the task. Already stressed to and at times beyond its limits, the lightweight frame was likely not capable of dealing with the much higher loads produced by 1981-specification, slick tyres. Using the drawings supplied by Porsche and a higher gauge material, a new, sturdier frame was built. The new chassis tipped the scales at 65 kg compared to 50 kg of the original. The suspension geometry was also altered to make the most of the latest tyre technology.
Porsche offered Kremer Racing a choice of two versions of the Type 912 engine. The first was the 4.5-litre unit of the flat-12 that had powered the 917 early in its career and the second was the larger, 5-litre engine fitted to the later developments. While the second option was obviously more powerful, it was also thirstier. Taking into consideration the particular needs of the Le Mans track with its long straights, the Kremers understandably opted for power over frugality. Producing around 600 bhp, the big engine was mated to the tried and trusted five-speed gearbox. Page 1 of 2 Next >>