The Super GT series is without a doubt one of the most exciting GT racing series in the world. You might think there’s a particular spot of success to it due to a single factor but if you’ve been for even a single race, it’s clearer than transparent cam pulley covers that the profound success of the Super GT is due to a cocktail of Japanese elements that accompany it and pull in the fans to create a carnival-like atmosphere that is somehow lacking in other racing series’.
While the GT Queens and pit walk as well as the circuit safari would definitely be crowd pullers, at the end of the day, the GT machines of the series are what keep the fans coming back for more. Super GT regulations are one of the most lenient or relaxed compared to other GT racing series. As a result, the top tier GT500 cars are possibly the fastest GT racing cars in the world.
As you would already know, there are two tiers in the Super GT series, the GT500 and the GT300. As the name suggests, the GT500 cars are capped at 500hp while the GT300 cars at 300hp, meaning that once the air restrictors are put into effect, no car will make over the stated horsepower figures.
Here we will be taking a look at the Nissan GT-R that is raced in the GT500 class and some of the differences that sets it apart from its road-going counterpart. With the more relaxed regulations employed in the GT500 class, participants are allowed to make a plethora of changes ranging from using different engines as the road car but from the same manufacturer to completely changing the alignment of the engine such as from front-mounted to mid-mounted.
However, the GT300 class, being contested more by privateers, is much more regulated, hence keeping the cars much more similar to their road-going versions.
To begin with, the Nissan GT-R used in the GT500 class is no longer powered by 3.8-liter twin-turbocharged mill that has seen catapulted it to the supercar status. Instead, as regulations require a 3.4-liter naturally-aspirated V8 lump to be used, the VRH34A engine is used. Based on a production engine, it has been extensively modified to cope with the rigours of Super GT racing and produces in access of 450hp although the exact figure is unknown. The engine configuration though s maintained as well, giving it a front-engine, rear-wheel drive layout.
Super GT regulations prohibit all-wheel drive, hence the switch to the more traditional racing layout of rear-wheel drive. Furthermore, the twin-clutch setup used in the road car has been ditched for a more race-worthy six-speed sequential that is mounted in the rear by a transaxle that is connected to the driveshaft via 5.5-inch carbon triple plate clutch.
Although engine limitations aren’t tight, there are a number of systems used to maintain parity between the teams. The primary one, as we mentioned earlier, is the use of air restrictors to limit the power of the car to keep things competitive. As an example, a car that is more powerful or considerably faster will be given a larger air restrictor to lower its power and keep it on a level playing field with the other machines. Similarly, if a car is struggling to keep up, a smaller restrictor will be used to give it more power. All this is done during testing and scrutineering in the pre-season.
Under the carbon fiber that extensively clads the body, the Super GT GT-Rs share almost no resemblance to their ones that roll off the Nissan assembly line. The gist of it is that it shares the same cockpit shape, headlights, tail lights, front grille and door knobs. That’s where the similarities end.
Interestingly, the wheels used measure 18-inches up front, wrapped in 330/40-R18 sticky Bridgestone slicks while the rear goes a size smaller at 17-inches, wrapped in the same 330/45-R17 rubbers. Perhaps there’s a reason to this but it definitely strays far from the norm of running larger wheels at the rear for rear-wheel drive machines.
Weight is a race engineer’s worst nightmare and the Super GT GT-R has undergone a rabid diet to shed over 500kg by means of removing all unnecessary parts and systems as well as the healthy use of carbon fiber almost everywhere.
Even though the GT-R was introduced as a new car in the 2008 series, it went on to dominate the opening round by claiming a one-two finish, leading to an immediate weight penalty, part of the system to maintain parity. The additional 50kg, which when added to the weight penalty from qualifying made it closer to 100kg, still didn’t hinder the car one bit as it took the win in the second round as well, proving the racing history and know-how of Nissan was a force to be reckoned with.
Source: Nissan Motorsports
