Group GT3

Group GT3, known technically as Cup Grand Touring Cars and commonly referred to as simply GT3, is a set of regulations maintained by the Fédération Internationale de l'Automobile (FIA) for grand tourer racing cars designed for use in various auto racing series throughout the world. The GT3 category was initially created in 2005 by the SRO Group as a third rung in the ladder of grand touring motorsport, below the Group GT1 and Group GT2 categories which were utilized in the SRO's FIA GT Championship, and launched its own series in 2006, the FIA GT3 European Championship. Since then, Group GT3 has expanded to become the de facto category for many national and international grand touring series, although some series modify the ruleset from the FIA standard. By 2013, nearly 20 automobile manufacturers have built or been represented with GT3 machines.

Group GT3 allows for a wide variety of car types to be homologated with almost no limit on engine sizes and configurations or chassis construction or layout. GT3 cars must be based on production road car models in mass production. Performance of all the Group GT3 cars are regulated, either by the GT Bureau of the FIA or by a series' specific ruling body, through a Balance of Performance that adjusts limits on horsepower, weight, engine management, and aerodynamics to prevent a single manufacturer from becoming dominant in the class. The cars in GT3 are designed to have a weight between 1200kg and 1300kg with horsepower between 500hp and 600hp. All cars have a very similar power to weight ratio but achieved either by high power and high weight such as the Mercedes-Benz SLS AMG or low power and low weight such as the Porsche 911 GT3. GT3 cars also have traction control, ABS and built in air jacks for quick pit stops.

The concept behind Group GT3 was introduced by Stéphane Ratel, head of the SRO Group and promoter of the FIA GT Championship in 2005. The Group GT1 and Group GT2 cars in the FIA GT Championship required manufacturers to build a car based on regulations, and then develop that car to increase its performance, thus increasing the cost for the manufacturers and the customers wanting to race the cars. GT3 was envisioned as a category that would simplify the process by combining several existing cars from one-make series, such as the Porsche Supercup or Ferrari Challenge, as well as other race cars available from manufacturers that did not fit in GT1 or GT2, such as the Aston Martin DBRS9 or Dodge Viper Competition Coupe, and allow them to all compete on a level playing field through strict control of their performance by the FIA. This would allow drivers a bridge between smaller national series and the professional international FIA GT Championship. Further, the category was conceived to use sprint formats for races, but manufacturers could develop and sell an upgrade kit for their cars to allow GT3 cars to be used in endurance races. A similar category, under the same name, had been in use in the British GT Championship which the SRO Group also organized.

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