

Car of the Day - Audi R15 TDI
Audi followed the enormously successful R10 TDi with the R15 TDi in its campaign for a ninth outright win at Le Mans in 2009. The R15 is more aerodynamiclly efficient, lighter and utilises a more compact, lighter and efficient engine.
For Audi's second generation turbo-diesel sportscar, gone was the 5.5 litre V12 to be replaced by a 5.5 litre V10. Audi have always stated they are more interested in Le Mans and Sportscar racing than Formula 1 as it provides a series where the cars are more relevant to standard production road cars and development is primarily about efficiency. The new V10 delivered improvements in both fuel consumption and CO2 emissions.
The R15's output is reduced by 50 hp from the R10, now down to 600 and torques matches that down from 1100 nM to 1050 Changes to the turbo-charging and fuel injection improved engine response and that coupled with the lighter weight resulted in a much more nimble car. The focus of Audi's diesel program with the R10 had been efficiency over speed, with the R15 Audi wanted to re-introduce the speed factor, not that the R10 was any slouch..
Dr. Wolfgang Ullrich, Head of Audi Motorsport states, "The R15 TDI has many detailed technical solutions never seen before on a sports prototype. To a certain extent we followed entirely new routes." The use of CFD (Computational Fluid Dynamics), which Audi had used for aerodynamcially tuning the 2008 DTM Championship winning A4 resulted in a rear wing suspended from the top, an elevated nose and suspension and numerous other aero details to reduce drag, improve airflow where required and increase downforce when needed.
The electrics sees the introduction of a lightweight lithium-ion battery as used in some hybrid vehicles. That battery powers light emitting diodes for low bean in the headlights. The use of LEDs is becoming a distinct design feature across the Audi line.
2009 was the year that car manufacturers were pulling out of race services left right and centre and Audi was no different. Management decided to forgo the American LMP1 series in favour of an all out effort for Le Mans with the Sebring 12 hour being used for testing and development. Full race results, drivers and chassis rundown for Sebring and Le Mans will follow in part 2 of this car of the day. While the R15 proved successful at Sebring we all know that Peogoet really upset the apple cart with their win at Le Mans.
Rod Halligan























































