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 led 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 1984. Rise and fall By 1989, the Group C series popularity was nearly as great as Formula One. When C1 cars were found to be breaking over the 400 kilometres per hour mark at Le Mans' Mulsanne Straight — the WM-Peugeot recorded the highest during the 1988 event — the FIA revolutionized the class by attempting to turn it into a formula series to replace the C2 category (after they proved to be unreliable at endurance races). The new formula restricted the performance of cars built to the original rules (such as the Porsche 962 used by many privateers) and benefited teams using F1-sourced 3.5 L engines — these latter teams being effectively the large manufacturers alone, as the new formula cars were more expensive than the C1 cars. What followed was