Are you new to Sports Cars Racing? Curious about the differences between LM GTE & GT3? Curious about the difference between LM GTE? No worries, we’ve got you covered. Ahead of the resumption of motorsport worldwide, we’ve decided to produce articles introducing Sports Car Racing to our readers. Part 3 is an in-depth introduction to the main GT classes used in Sports Car Racing today.
GT, or Grand Touring racing, is by far the most common form of sports car racing, and can be found globally, in both international and national series. Unlike Prototypes, GT Race cars must be based upon a production vehicle. In addition, to be eligible to race, a minimum production number must be met. Currently, GT Racing comprises of 6 main categories:
- GT300 & JAF GT300 Mother Chassis
- LM GTE
GT500 cars are built to the JAF/ITR Class One regulations, shared with the DTM. GT500 cars are the fastest GT class in the world, being faster than even the LMP2 Prototypes. GT500 cars are the most aerodynamically advanced GT cars, being silhouettes built atop a common chassis.
All cars are front engine-d and have a single element rear-wing. Previously, the regulations allowed for mid-engine designs, but for 2020, that has been outlawed, and the NSX GT500 is now front-engine. All cars use a 2 litre in-line 4 engine paired with a 6-speed paddle shift gearbox producing between 700-600 horsepower.
GT500 uses success ballast, capped at 100kg. Despite this, cars only carry 50 kg in physical ballast. Fuel flow restrictors represented the additional ballast, applied in three-stage increments. GT500 is an open-tyre class.
GT300 is a name that is applied to 2 different sub-classes, GT300 and GT300 Mother Chassis (MC). JAF GT300 cars are heavily modified versions of their road going counterparts, and use the original car’s engine. JAF/GTA GT300 MC Cars are silhouettes, built atop a common mother chassis built by DOME Racing, and utilise a common V8 GT Association badged Nissan V8 engine. In both sub-classes, engines must be in the original position as that in the road going car. Previously, this rule did not exist, and several cars, most notably the Prius GT300 took advantage of it. Despite the GT300 tag, most engines produce a power output exceeding 400 horsepower
GT300 cars compete against FIA GT3 cars in the Super GT Championship with Balance of Performance applied. Compared to FIA GT3 cars in Super GT, JAF GT300 cars have more downforce, and are lighter, but have less horsepower.
GT300 uses Success ballast capped at 100kg of physical ballast. GT300 is an Open Tyre class, with a tyre war between Yokohama, Bridgestone and Dunlop. This tyre war is also one of the reasons why the Super GT GT3 cars are much faster than the standard GT3 cars.
The GTE class is used in the FIA WEC, IMSA WeatherTech Sports Car Championship (run as GTLM), ELMS. The class had its origins in the N-GT class of the FIA GT Championship, which was renamed as GT2 in 2005. The GT2 class was later renamed as LM GTE in 2011, after the ACO removed the GT1 category from ACO sanctioned competition.
The class is split into 2 categories, GTE-Pro and GTE-Am, with the Pro class having no restrictions on driver line-ups, while Am class requires the use of 2 Amateur drivers, with 1 driver being Bronze rated, and a second driver being either silver or bronze rated. GTE Am class teams are also only allowed to run cars that are at least one year old. For example, the Porsche 911 RSR 2017 can only be run in 2018 in the Am class)
Engine size is limited to 5.5L for Naturally Aspirated engines, and 4L for Forced Induction engines, although waivers may be given. Engine based Traction Control is allowed, and is the only driver aid allowed. Four-wheel drive is banned. Balance of Performance is applied, and success ballast is also applicable for the GTE Am class
- Maximum dimensions:
- Overall length: 4800 mm
- Front overhang: 1250 mm
- Rear overhang: 1100 mm
- Overall width: 2050 mm (excluding rear view mirrors)
- Minimum weight of 1245kg excluding BoP
- Fuel Capacity of 90 Litres excluding BoP
- Cars must also have a rear-view camera, in addition to side mirrors
GT3 is the most popular GT class globally, used by major and national GT Championships globally, such as the Intercontinental GT Challenge, GT World Challenge Europe/Asia/North America, British GT Championship, and the ADAC GT Masters. GT3 was introduced in 2005 by the FIA and the Stephane Ratel Organisation (SRO) as the third rung on the GT racing ladder, below the GT1 and GT2 categories which were used in the FIA GT Championship. GT3 was originally designed as a Pro-Am class. However, it is used today as both a Pro-Pro and Pro-Am class
GT3 technical regulations are relatively open compared to other classes, and are designed for manufacturers to easily adapt their cars for racing, pegged back with Balance of Performance. As such, GT3 grids can boast diverse fields, with Bentley Continental GTs competing against Honda NSXs, with car performance equalised through Balance of Performance measures, which can include mandatory wing angles and additional ballast. Compared to GTE, less bespoke racing components are allowed, while ABS is also allowed, and GT3 cars are less aerodynamically complex. Like GTE, Four Wheel drive is prohibited
GT2 is a relatively new class of racing introduced in 2019. Despite its name, it is slower than GT3 and sits between GT3 and GT4 pace wise. Targeted at amateur drivers.
Compared to GT3, it GT2 cars have a higher power output, higher top speeds than GT3 cars, with simpler aerodynamics. Homologation is done by the Stephane Ratel Organisation (SRO), and it is used mainly in the SRO GT Sports Club.
Currently, only 3 cars are homologated in the class, the Porsche 911 GT2 RS Clubsport, the Porsche 935 & the Audi R8 GT2
GT4 is currently the lowest rung on the GT racing ladder, and it was introduced in 2007 in the GT4 European Cup. It is the second most common GT Class globally, used in national and regional GT Championships.
It is an amateur class for those starting out in GT racing, having the lowest power output, and the highest number of driver aids. It features substantially cut-down aerodynamics compared to GT3. The homologation is held by the Royal Automobile Club of Belgium