GT Racing Insights
By Ben H. September 2 2020
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 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.
GT3 is the most common spec of professional race cars globally. The cars compete in series like IMSA under the GTD name and SRO championships worldwide, including GT World Challenge Europe, America, and Asia, and smaller championships such as British GT and ADAC GT. The idea of GT3 regulations is for a manufacturer to turn one of the existing models into a pure-bred race car.
With changes in engine, gearbox, suspension geometry, and track width, all permitted, the manufacturer can invest as much as they want to develop the car and make a return on the investment by selling them to customer teams around the world. GT3 cars boast infinitely adjustable ABS and traction control systems specifically designed for the racetrack along with significant aerodynamic grip. Compared to their GT4 siblings, they are typically close to 10 seconds a lap quicker.
The most common GT3 cars racing around the world are the Aston Martin Vantage GT3, Lamborghini Huracan GT3, McLaren 720 GT3, Audi R8 GT3, Porsche 911R, and Bentley Continental GT3. Each of these utilizes different engines. These engines range from the naturally aspirated V10 in the Audi and Lamborghini to the twin-turbo V8 in the McLaren, Bentley, and Aston Martin. Of course, you can’t leave out the naturally aspirated flat 6 in the 911R. All cars utilize a paddle operated semi-automatic gearbox equipped with a foot clutch for pulling away from a stationary position in the pitlane or grid.
GT3 cars are the Gentlemen/Lady driver’s target, typically racing in the larger endurance races around the world, such as the Daytona 24-hour and the Bathurst 12-hour. They can have up to 3 teammates, a mix of pro and amateur drivers, to compete in the races. GT3 is the perfect platform after graduating from GT4 cars.
GTE or Grand Touring Endurance cars are the highest level of GT racing cars in motorsport and are specifically designed to tackle the 24 hours of Le Mans. These are typically run by factory teams only with professional drivers as the budgets are generally too large for a gentlemen driver. However, there is the GTE AM class in the World Endurance Championship that requires a single gentlemen driver in each car in the category.
The cars race in the World Endurance Championship (WEC) and IMSA (under the GTLM name). For a car to meet the GTE regulations, it needs to fulfill specific requirements. They are faster than GT3 cars with more horsepower and significantly more downforce. Traction control is permitted; however, the use of ABS is not. The engine must be a derivative from a series production engine with at least 300 units produced and fitted to a series of vehicles made by the manufacturer.
Direct Injection is also forbidden unless fitted to the series-production engine of the manufacturer. If the manufacturer chooses to use a turbocharged engine, an anti-lag system is permissible to spool up the turbos to eliminate turbo lag. The Ford GT GTE car has an anti-lag system fitted onboard and can be heard in onboard footage when the driver lifts off the throttle.
The suspension geometry can be changed entirely from the road-going version of the car to get the best performance in the race. Examples of GTE cars include the Ferrari 488 GTE, the Porsche 911RSR, the Corvette GTLM, the BMW M8 GTE, and the Aston Martin Vantage GTE.
The Ultimate Car Race
The idea of the GTE regulations is to create a “halo” car for each manufacturer competing, which also has a similar counterpart driving on the road. With each manufacturer demonstrating the best engineering they can offer, the competition reveals who has done the best job.
Any GT team competing in the European Le Mans Series, the Michelin Le Mans Cup, the IMSA WeatherTech SportsCar Championship, and the Asian Le Mans series can be invited to compete in the 24 hours of Le Mans. Each year invitations are sent out based on the previous season’s results in their respective championships.
As Le Mans is the ultimate test of man and machine, it is imperative to ensure everyone competing is up to the task of the world’s greatest endurance race.
In conclusion, the ladder that the FIA has created with GT racing has become an effective way to bring professional and amateur drivers from their first steps in professional racing all the way to the 24 hours of Le Mans, the ultimate car race.