Group C

Did You Know?

• Group C was designed to replace both Group 5 special production cars and Group 6 two-seat racing cars.
• Group C Junior was introduced for 1983 and formally renamed Group C2 for 1984.
• The 1993 World Sportscar Championship was canceled before the first race due to a lack of entries.
• The Dauer 962 Le Mans, a modified Group C car disguised as a road-legal GT, won the 1994 24 Hours of Le Mans.

History

The origins of Group C trace back to the GTP class introduced by the ACO at Le Mans in the mid-1970s, which placed restrictions on fuel consumption rather than engine size. The FIA applied this concept to Group C, setting a minimum weight of 800 kg and a maximum fuel capacity of 100 litres. Competitors were limited to five refueling stops per 1000 kilometers, effectively allowing 600 litres of fuel for that distance. This approach aimed to curb the trend of manufacturers relying solely on engine development, as seen in the late 1970s when cars like the Porsche 935 could exceed 800 hp. Engines had to come from a manufacturer with cars homologated in Group A or Group B. The rules allowed large naturally aspirated engines to compete with smaller forced induction units. All races were at least 1000 km long, emphasizing endurance. Ford with the C100 and Porsche with the 956 were the first constructors. Other manufacturers including Lancia, Jaguar, Mercedes, Nissan, Toyota, Mazda, and Aston Martin later joined. Many also competed in the IMSA GTP championship.

Rise and fall

By 1989, Group C's popularity rivaled that of Formula One. After C1 cars reached speeds over 400 km/h on the Mulsanne Straight—the WM-Peugeot recorded 405 km/h in 1988—the FIA overhauled the class, aiming to replace the C2 category. The new formula restricted cars built to original rules, such as the Porsche 962, and favored teams using F1-sourced 3.5 L engines, which were more expensive and largely affordable only by large manufacturers. This led to a rapid decline, as privateer teams like Spice and ADA could not afford the new engines. The 1993 championship was canceled before the first race. The ACO still allowed Group C cars at Le Mans with restrictions, but spectators protested. The 1994 Le Mans was the last to permit Group C cars. A modified Group C car disguised as a road-legal GT, the Dauer 962 Le Mans, won after a leading Toyota 94C-V had transmission problems; the 962 was subsequently banned. The Toyota received a special dispensation for the Suzuka 1000km, and some C1 cars competed in the new Japanese GT Championship. Modified open-top Group C cars continued until they were crashed, broke, or retired; the Porsche WSC-95, using a Jaguar XJR-14 monocoque and Porsche 962 mechanicals, won Le Mans races.

Group C series

The FIA's Group C formula was primarily for the World Endurance Championship, which included the 24 Hours of Le Mans. The Deutsche Rennsport Meisterschaft allowed Group C cars alongside other types from 1982 to 1985, after which the series became the ADAC Supercup, exclusively for Group C cars until 1989. In Great Britain, the Thundersports championship combined various cars with C Junior (later C2) class cars, later replaced by the BRDC C2 Championship, which lasted until 1990. The European Interserie also allowed Group C cars without using the same class structure. In Japan, the All Japan Sports Prototype Championship began in 1983, and the Fuji Long Distance Series also admitted Group C cars; both concentrated solely on Group C from 1989 until they were canceled in 1992.