All Japan Grand Touring Car Championship
All Japan Grand Touring Car Championship is a grand touring car racing series that began in 1993. Originally titled as the Zen Nihon GT Senshuken, the series was renamed to Super GT in 2005. It was the top level of sports car racing in Japan.
The series was sanctioned by the Japan Automobile Federation and ran by the GT Association. Autobacs has served as the title sponsor of the series since 1998.
History
The JGTC was established in 1993 by the Japan Automobile Federation via its subsidiary company the GTA, replacing the defunct All Japan [Sports Prototype Championship] for Group C cars and the Japanese [Touring Car Championship] for Group A touring cars, which instead would adopt the supertouring formula. Seeking to prevent the spiraling budgets and one-team/make domination of both series, JGTC imposed strict limits on horsepower, and heavy weight penalties on race winners in an openly stated objective to keep on-track action close with an emphasis on keeping fans happy.Image:R34 Xanavi Skyline 001.JPG|250px|thumb|left|2003 Xanavi nismo GT-R (R34).
In its first season, the JGTC grid mostly consisted of cars, with the only genuine JGTC cars being a Nismo-entered Nissan Skyline GT-R and Nissan Silvia S13, of which the GT-R was a modified AWD Group A car. An exception was the first race of the season, which was also an exhibition race of the IMSA GT Championship, and therefore saw a contingent of GTS and GTU cars from the American series join the field. The 1000 km Suzuka also saw a greater variety of competitors, with Group C prototypes, Group N touring cars, and GT cars from Europe and IMSA all joining the field.
For the following season, the series would undergo a rules overhaul, creating a class for the FIA's GT1 category, and another for the GT2 category. The JSS series would altogether dissolve into the latter category. What made the series more significant was that compared to other racing series, JGTC teams at the time had the freedom to enter whichever cars they preferred, even if it was the JSS cars from the inaugural season or spaceframe racers from the IMSA GTS class. However, the Group C prototypes, whilst easily showing dominant form, were banned from the series from the 1995 All Japan [Grand Touring Car Championship|1995 season] onwards.
By the end of the 1995 season, as the cost of obtaining and running a GT1 car had dramatically increased, the JGTC would go through another rules overhaul in order to lower costs and avoid the fate of the JSPC series it had replaced. The newly formed GT500 and GT300 regulations were adopted, which capped cars with air restrictors depending on their amount of weight and horsepower. While the regulations would continuously evolve, the GT500 and GT300 classes continue to form the top level of Japanese sports car racing today.
The cars
The cars are divided into two groups: GT300 and GT500. The names of the categories derive from their traditional maximum horsepower limit - in the early years of the series, GT500 cars would have no more than 500 horsepower while GT300 cars would max out at around 300 hp and have far less downforce than their GT500 counterparts. While the current generation of engines in GT500 and GT300 cars produced a horsepower output in excess of the traditional limit, the limit stayed in place throughout the entirety of the JGTC era.In both groups, the car number is assigned to the team, in which each team is allowed to choose whichever number they want as long as the number isn't already used by any other team. The number assigned to each team is permanent, and may only change hands when the team exits the series. In addition, only defending team champions in GT500 are allowed to use number 1, although it isn't mandatory for defending champions to use that number.
For easy identification, GT500 cars run white headlight covers, windshield decals, and number panels, while GT300 cars run yellow versions of those items.