Sports car racing is one of the most popular forms of racing in the world. The races contain different specification Grand Touring cars called GT for short. Compared to other motorsports, GT racing is a complex category with multiple different specifications of cars often competing in the same race. If you have ever watched an IMSA race, you will be familiar with the GTLM and GTD cars. Each car specification category usually has its own standings within the race itself.
We will help you understand what you need to know about the three most popular specs of GT cars that race around the world. The FIA has created a GT racing ladder that begins with GT4 race cars, which share the most components with road cars, GT3 cars in the middle, and GTE or GTLM at the top of the ladder. GTE cars are fully-optimized for professional racing.
GT4 cars are the entry-level to the professional racing world, often with their own series such as European or American GT4, or shared races with GT3 cars like British GT and the 24-Hour series. GT4 cars are the closest relative to their road-going counterparts, which share the same engine, gearbox, and differential for reliability and simplicity purposes.
The major changes made for a car to compete in the GT4 category are adjustable dampers and revisions to the suspension geometry, electronics, cooling, and braking systems. The braking system is often carried over from a GT3 car to ensure consistent brake life, along with the same basic traction control and ABS. However, they are significantly less adjustable in a GT4 car than their GT3 counterparts.
GT4 cars often have lower cornering speeds, due to having less aerodynamic grip than GT3 cars, and slightly less power, usually developing between 380-450 horsepower. The electronics you would expect to find in a GT4 differ from model to model. For example, the BMW M4 has the same wiring loom as the road car, and it is just the programming that is modified, but the Aston Martin GT4 has a race car specific wiring loom. The 2018 BMW M4 GT4 car takes a lot of its interior design from its faster brothers, the M6 GT3 and M8 GTE. The interior has been replaced with a carbon dash and central control panel with a multi-function racing steering wheel.
The BMW’s interior has a similar layout to the Aston Martin Vantage GT4 and Toyota Supra GT4. The McLaren 570s GT4 has the most in common with the road cars as it shares the same dash and center console found in the road car equivalent, along with very similar traction control and ABS. On the other hand, the BMW and Aston Martin have upgraded traction control and ABS compared to their road-going cousins.
All GT4 cars come standard with a rear-view camera to ensure the driver has the best visibility behind them. The road cars’ fancy interiors are gone and are replaced with a roll-cage, five-point harness, racing seat, central dash, and fire suppression system required in all FIA homologated cars.
GT4 cars are typically where a Gentlemen or Lady driver would begin their professional motorsports career. The idea is that they hire a team and an experienced driver to work with them as a pro-am driver pairing. The professional driver acts both as a coach to help the Gentlemen/ Lady driver improve, and as a co-driver during the races, typically completing 50-60% of the race distance. GT4 cars are the perfect starting platform because they are the simplest to understand technically, helping a beginner set-up their car exactly how they want it.