Audi R10 TDI Development

The idea to develop a diesel sportscar for the 24 Hours of Le Mans had already emerged in 2002 with the internal project name “R10” which ultimately became the new Le Mans sportscar’s official type designation – just like its successful predecessor the R8.

Things became very serious in September 2003 when the concept guidelines for the new Audi R10 TDI were determined.

“That was the most important stage,” says Ulrich Baretzky, Head of Engine Technology at Audi Sport. “You have to define the number of cylinders, the engine’s length, bore and stroke. Everything else results from these basic dimensions. If you make a mistake at this stage, it is almost impossible to correct later. That’s why we considered every facet very carefully before we fixed the package.”

In Spring 2004, the decision was made to select a twelve-cylinder engine with the maximum permissible cubic capacity of 5.5 liters allowed for Le Mans, which also affected the chassis. “Compared with the R8, the engine’s length has grown through the number of cylinders, and because of a diesel’s typical power and strength,” explains Wolfgang Appel, Head of Vehicle Technology at Audi Sport. “In this respect we had to react by making everything as light as possible on the chassis side.” The R10 TDI has a significantly longer wheelbase as a direct result of the large capacity engine.

The Le Mans V12 TDI ran for the first time on the test bed in July 2005. “It was incredibly interesting, because we really have explored completely new territory with this engine,” says Ulrich Baretzky. “Previously, together with our colleagues from the production car development, we had made basic tests with modified production engines and a single-cylinder model. That was all!”

The new power unit had already clocked-up approximately 1000 test-bench hours, including several endurance runs, before the R10 TDI prototype’s roll-out on 29 November 2005. The V12 TDI will have almost 3000 test-bench hours to its credit and several thousand test kilometers in the back of the R10 TDI before Le Mans.