Last year, Audi ran two versions of its R18 e-tron quattro racecars: one more aerodynamic than the other. This year, though, Audi will be testing a third variant it’s calling the “long-tail,” which has been optimized for high-speed Le Mans tracks.

The idea of the long-tail is not to see which version goes around the entire circuit fastest but rather which performs best in differing sections of the raceway. Audi will take that information and tweak the cars it intends to enter in the Le Mans 24 Hour.

But what is underneath the long-tail, carbon fiber body? Believe it or not, it’s a hybrid diesel car.

Audi’s R18 e-tron quattro is powered by a 3.7-liter V6 turbocharged TDI diesel engine, which produces 510 horsepower and upwards of 626 pound-feet of torque. Additionally, the specially built racecars feature an electric flywheel and a water-cooled motor generator unit in the front axle. In the middle of the system is a sequential, electronically activated six-speed transmission.

Distinctively, the cars are rear-wheel drive up until around 75mph. Then, the electric unit kicks in, which powers the front wheels for improved traction and power delivery. Although it’s not a traditionally quattro system that customers might find underneath the Audi models at their local dealership, systems like that of the R18 might someday soon make their way into production cars.
If you have a chance to watch the Spa race somewhere, we recommend you do. Audi has quite a competition going on with the Toyota team right now. Audi R18 e-tron quattro driver, André Lotterer, considers the Spa track his ‘home’ so it should be an exciting showdown.

We’ll bring you more about the long-tail R18 after the race is done so check back for a deeper dive into its distinctive long body design and unusual drive systems.