Christopher Reinke, Manager of Audi's Le Mans program, sat with our motorsports guru, Marshall Pruett, to give us an inside look at what makes the 200-mph Audi R18 e-tron LMP1 racer tick. Read on for a point-by-point breakdown of what's going on beneath the car's carbon fiber skin.
The numbers below match up to the points highlighted in the cutaway image posted above.
1. Routing the exhaust along the top of the gearbox made Audi look to F1 for answers. The result is a pullrod rear-suspension design similar to the back of Sebastian Vettel's championship-winning Red Bull RB8.
2. At 90 mm, the R18's inconel (a high-performance metal alloy) exhaust is large enough to hurl anti-tank shells. It houses a particulate filter to keep it from puking clouds of black smoke.
3. Audi introduced the P1 class's first carbon gearbox housing. "Because we added the hybrid system, we had to look at [saving grams] to bring weight back down. This tech has been used in F1, but it's never had to deal with diesel torque or last for 24 hours. We'll use this case for the entire season."
4. What looks like a carbon-fiber oil bottle actually houses the variable-turbine-geometry (VTG) controller. "We have only one turbo, and it's quite big. With this, we can change its geometry and achieve performance across a wide range."
5. The exhaust on the 3.7-liter turbodiesel V-6 recalls the "bundle of snakes" headers on 1960s open-wheelers. "The request came from the aero department," Reinke says. "By turning around the cylinder heads, we were able to have a narrower package on the bottom of the engine, which let us feed more air cleanly out of the radiators."
6. "Aerodynamics are critical in F1, and many of the same decisions are now being made in endurance racing," says Reinke. "There is a minor [center of gravity] penalty by moving the exhaust higher, but it's grossly outweighed by the effects of feeding air into the engine from below, which cleans up the airflow inside the R18." Routing the exhaust along the top of the gearbox made Audi look to F1 for answers. The result is a pullrod rear-suspension design similar to the back of Sebastian Vettel's championship-winning Red Bull RB8.
7. "700 lb-ft, more than 500 hp, and 40.6 psi of boost."
That's the first seven points. For the latter half of the rundown, head over to Road & Track.