Since its creation in 1923, the 24 Hours of Le Mans Race has emerged as a true technical laboratory for carmakers as well as their partners. This vocation has been such over the years, that it has had an influence on the regulations – and thus the very nature – of endurance racing. The creation of an energy efficiency index in 1959 soon became an important feature of the race.
In the same spirit, endurance racing quickly embraced various types of cars: on the same grid we can find racers derived from road cars, as well as pure purpose-built racing machines. At present, two distinct families of cars are racing in the 24 Hours of Le Mans and the World Endurance Championship (WEC): prototypes and GT cars. Both are divided into two categories.
LMP1 is considered to be the elite among the prototypes of endurance racing. Since 2014, this category has benefited from bold technical innovations that have made the hybrid a worthy contender. By now the LMP1 category has become the research model in studying energy efficiency. Each car is allocated a specific amount of fuel for each lap.
In endurance racing a wide variety of engines is permitted. The V6 turbo diesel engines of Audi are battling it out with the turbo hybrid V8 of Toyota, or the 4-cylinder 2 liter turbo of Porsche. By combining combustion engines and hybrid systems, the power of the LMP1 can increase up to 1000 Hp.
The LMP2 class is intended to be accessible to amateurs. At least one amateur driver must be registered as part of the line-up. Costs are strictly controlled by the rulebook. Similarly, the number of engine is limited (3 for a WEC season). This year, six types of chassis and three types of engines will be fiercely joined in battle. Ten competitors are registered in this category in the World Championship and there will be 23 of them at the 24 Hours of Le Mans!
Symbolizing the link with the manufacturers, the GTs include two categories: GTE Pro and GTE Am (E meaning Endurance). A GT car is derived from a road car that has already been produced at a minimum of 100 units. The shape of the road version should be respected, and the engine's position is regulated. However the GT class includes cars in very different forms. Aston Martin and Corvette have a front engine (aspirated V8), while Porsche has a rear mounted 6 cylinders boxer, Ferrari a mid mounted twin turbo V8 and Ford GT a mid mounted twin turbo V6. Fifty years after winning the 24 Hours of Le Mans Race with the legendary GT 40, the American company is making its comeback with a new generation of cars.
If the GTE Pro category is the prerogative of the factory squads, then the GTE Am class is that of the amateur teams. The cars are at least one year old, and do not benefit from the latest enhancements fitted to official cars.
Visual codes distinguish the four types of cars. Prototypes are fitted with white headlights while the GT's have yellow lenses. Each category has race numbers on a specific coloured background: red for LMP1, blue for LMP2, green for GTE Pro and orange for GTE Am.