Le Mans Diary: Wednesday June 13 Le Mans, Wednesday June 13, 10.30 Amongst contenders for the title "greatest race in the world," Le Mans has one ace - a multi-class format creating not one race but many races in one. In 2012 that means four distinct classes, LMP1, LMP2, GTE Pro and GTE Am, plus the subtler distinctions in LMP1 of "conventional" petrol versus diesel, and now petrol Hybrid versus diesel Hybrid. Both "P" classes define (notionally) two-seat "Prototype" cars, open or closed, with any chassis/engine layout. LMP1, province of manufacturer teams Audi and Toyota, inevitably provides the outright winner, and includes the recently all-conquering diesels and now Hybrids. The defining limits are minimum weight (900kg), maximum engine size (depending on fuel, and turbo or non-turbo), plus fuel capacity (significantly less for diesels, fractionally less again for either species of Hybrid). "P2," realm of privately entered (and currently petrol-only) Prototypes, is cost-capped (at €355,000 for the chassis, €75,000 for the engine), shares P1"s 900kg limit, has its own turbo/non-turbo capacity and number-of-cylinder rules, and a 75-litre fuel limit. Each P2 also has to include one "amateur" in its three-driver complement - but LM's definition of "amateur" probably differs from yours or mine. Driver status also differentiates the latest GT classes, GTE Pro (E for Endurance) and GTE Am. Pro and Am cars (from Corvette, Ferrari, Porsche, Aston Martin) are essentially similar: racing developments of series-built GT cars, minimum weight 1,245kg, capacity according to turbo or non-turbo, fuel 90 litres. Pro has no driver constraints, and like P1 is effectively manufacturer-supported; Am allows only one "Platinum" driver, and Am cars have to have been available for at least a year in the same specification. Usefully, each class is identifiable by headlamp and number-background colours - which means that, even with many races in one, you can usually tell what's what.