In 1991, the World Sportscar Championship, which includes Le Mans, was renamed the FIA Sportscar World Championship. The change included revised regulations that bunched the various existing classes, such as C, C2 and GTP, into just two classes: Category 1 and Category 2. Category 1 stipulated naturally aspirated 3.5 liter engines with no fuel limit. Mazda entered Category 2, which allowed greater freedom in terms of displacement, number of cylinders and turbos, yet restricted cars to just 2,550 liters of fuel. The governing body had decided, however, that Category 2 was to be discontinued from 1992. After 16 years and 12 attempts, the 1991 Le Mans was to be the final chance for Mazda and the rotary engine.