Types of Sports Car Racing

There are many kinds of sports car racing that can be broadly broken down into two categories: Prototype racing and Grand Touring (GT) racing. These two categories are often mixed together in a single race.

Prototype racing is the highest level of competition in the classification of the Automobile Club de l'Ouest (ACO), the sanctioning body for Le Mans and the model for the American Le Mans Series. Prototypes are purpose-built racing cars, with enclosed wheels, and either open or closed cockpits. Regulations regarding bodywork, engine style and size, tyres and aerodynamics are comparatively open. Prototypes may be (and often are) one-of-a-kind machines, and need bear no relation to any road-going vehicle.

In the ACO classification system, two categories are recognised: P1 and P2. Cars competing in the P1 category must weigh no less than 900kg and are limited to 6000cc naturally aspirated and 3600cc turbocharged engines. P2 cars can weigh much less - 750kg - but are restricted to 3400cc aspirated or 2000cc turbocharged powerplants. On paper, the P2 cars are able to challenge the supposedly faster P1 cars due to their lighter weight, at the expense of less power. However, as of recent years the P2 cars entered have raced with debilitating reliability problems and in 2005 actually finished behind the slower GT1 class at Le Mans.

Grand Touring (from the Italian word Gran Turismo) racing is the most common form of sports car racing, and is found all over the world, in both international and national series. Under the ACO rules, Grand Touring cars are divided into two categories, Gran Turing 1 (GT1, formerly GTS) and Grand Touring 2 (GT2, formerly GT). GT1 cars are purpose-built race machines based upon production exotic cars with homologation production limits of 25 cars (for small manufacturers, such as Saleen) or 100 cars (for major manufacturers like DaimlerChrysler). As the name of the class implies, the exterior of the car closely resembles that of the production version, while the internal fittings may differ greatly. GT2 cars are very similar to the FIA GT3 classification, and are 'pure' GT cars; that is production exotic cars with relatively few internal modifications for racing. The Porsche 911 is currently the most popular car in the GT2 class.

FIA divides GT cars into 2 categories, called GT and N-GT. These divisions are very close to the ACO rules outlined above, and again some crossover racing does occur, particularly in the N-GT class. Historically, these are the GT2 and GT3 classes, merely renamed.

In 1998, FIA dropped the old GT1 category because of rising costs. The GT1 class was for the purebred supercars and purpose-built race cars, such as the McLaren F1. Rising costs coupled with declining entries led to the death of this class, and it was replaced by GT2 (FIA) and Le Mans Prototype (ACO).