The Super GT series, formerly known as the All-Japan Grand Touring Car Championship or JGT (全日本GT選手権, Zen Nihon GT Sensyuken), is a grand touring car race series promoted by the GT-Association (GT-A). Though the JGTC was authorized by the Japan Automobile Federation and recognized by the FIA, the Super GT is authorized directly by FIA.
The cars are divided into two groups: GT500 and GT300 (cars with no more than 500 and 300 horsepower (374 and 224 kW), respectively). These power outputs are capped via the use of intake restrictors although some heavier cars are given allowances to run larger restrictors to maintain parity.
In order to ensure maximum excitement, both GT500 and GT300 groups are run at the same time although points are awarded separately for each group.
GT500Regulations in GT500 are considerably looser than most GT classifications, and teams are free to change engines with other models made by the manufacturer, change the alignment of the engine, or add forced induction systems to models which do not normally have it. The chassis may also be heavily modified, with lightweight tube-frame "clips" being allowed forward and back of the main cockpit, although the car must overall look similar to its road-going variant. These regulations result in cars which are possibly the fastest GT racing cars in the world. The rationale for this was to allow manufacturers to field competitive cars without having to spend large amounts of money for homologation versions of the race car's road car counterparts (although some companies, notably Honda and Nissan, have still developed homologation specials).
GT300 cars are much more regulated than their GT500 counterparts, and much more closely resemble road-going versions. Chassis clips and realignments are not allowed (except the latter in the case of front-wheel drive cars), which results in a much more affordable racing experience for privateers. While engine outputs and modifications are at a lower level than the GT500 cars, the GT300 cars still post competitive times and races are very competitive.