Group C - History

History

The roots of the Group C category lie in both FIA Group 6 and particularly in the GTP category introduced by the ACO at Le Mans in the mid-1970s. GTP was a class for roofed prototypes with certain dimensional restrictions, but instead of the more usual limits on engine capacity, it placed limits on fuel consumption. The FIA applied the same concept in its Group C rules. It limited cars to a minimum weight of 800 kg and a maximum fuel capacity of 100 litres. With competitors restricted to five refueling stops within a 1000 kilometer distance, the cars were effectively allowed 600 litres per 1000 kilometers. The FIA hoped this would prevent manufacturers from concentrating solely on engine development; in the late 1970s, a few manufacturers (especially Porsche and Lancia) had dominated sports car racing by simply increasing turbocharger boost pressure, especially in qualifying trim — the 3.2 L Porsche 935 was capable of more than 800 hp. Engines had to be from a recognized manufacturer which had cars homologated in the FIA's Group A Touring Car or Group B GT Car categories.

While the consumption requirement meant that cars needed to conserve fuel early in the race, manufacturer support for the new regulations grew steadily with each make adding to the diversity of the series. With the new rules, it was theoretically possible for large naturally aspirated engines to compete with small forced induction engines. In addition, all races were to be contested over at least 1000 km — usually lasting more than six hours — so it was possible to emphasize the "endurance" aspect of the competition as well.

Ford (with the C100) and Porsche (with the 956) were the first constructors to join the series. The traditional turbocharged boxer engine in the 956 was already tested in the 1981 version of the Group 6 936. Eventually, several other makes joined the series, including Lancia, Jaguar, Mercedes, Nissan, Toyota, Mazda and Aston Martin. Many of these also took part in the IMSA championship, as its GTP class had similar regulations.

With costs increasing, the FIA introduced a new Group C Junior class for 1983. This was intended for privateer teams and small manufacturers and it limited cars to a minimum weight of 700 kg and a maximum fuel capacity of 55 liters. With competitors limited to five refueling stops within a 1000 kilometer distance, the cars were effectively allowed 330 liters per 1000 kilometers. As in Group C, engines had to be from a recognized manufacturer which had cars homologated in Group A or Group B. Although it was originally expected that C Junior cars would use two-litre normally aspirated engines, in practice most cars used either the 3.5l BMW M1 engine or the new 3.3l Cosworth DFL, but, like in the main class, a variety of solutions was employed by each individual manufacturer. Alba with a small, lightweight turbo, Tiga, Spice and Ecurie Ecosse with Austin-Rover and later Cosworth-powered cars were among the most competitive in this class. The low cost of these cars even lead to the notion of their use in national championships, such as the short-lived British BRDC C2 Championship. Group C Junior was formally renamed Group C2 for 1985.