FEATURE AUDI R18 TDI
more critical,’ says Audi’s technical director, Ralf Juttner. ‘Parallel to that, there have been some rule changes in the last few years which have changed the balance between the pros and the cons of open or closed cars, and that made us take the opinion that closed was the right way to go.’ Dr Wolfgang Ullrich, head of Audi’s Motorsport
division since 1993, was a firm advocate of the open design, with its increased appeal to American audiences who could easily identify a driver, and the faster driver changes during the pit stops. With information from the Bentley programme in 2001-2003, it re-affirmed Ullrich’s belief in the open car. However, Audi pulled out of the ALMS after the 2008
season, and new tyre changing regulations reduced the emphasis on fast driver changes. By the time the new engine regulations were
announced for 2011, even he had to concede that closed was better: ‘About one and a half years ago, we put a bubble over the cockpit of the R15 and put it in the wind tunnel. Te result was clear. It was going to be better, so we knew we had to make its successor a closed car.’
Testing times Te car rolled out for the first time at the end of November 2011, four months after the Peugeot 908 had its first track test, and since then testing has been both extensive and thorough. From the outset, the Audi R18 has given the team the speed needed to compete with Peugeot, and for the drivers, the confidence to constantly
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www.racecarengineering.com • August 2011
Audi’s mono-turbo V6 engine reduces losses as the air flows straight from the roof-mounted intake through the turbo and out through the single exhaust. Has Audi found an advantage by not loading the suspension through the gearbox casing, therefore potentially allowing a rapid change?
push to find the limits. ‘If out of the box, the lap times are quick, you know
that it is a good car,’ says driver Romain Dumas, ‘[but] if out of the box you are missing two seconds, you have to find a set up to find that time. Tis car had a first roll out and was already quick, and there is still a lot to go.’ By producing a closed car, the drag figures immediately
improved over the open-cockpit R15, and the reduction in downforce has not been a major factor in the performance of the car. Trough the Porsche Curves, and through Eau Rouge, the car is planted, solid and stable. ‘You have got to have a balance,’ says driver Allan
“a huge reduction in performance compared with the V10”
McNish. ‘When you have balanced aero, if you take aero off you have the same balance, but less grip. Te worst thing, whether in high or low aero spec, is if the car is imbalanced, then you will be slow.’ With less grip, the tyre characteristics are different,
and at the Spa 6-hours the difference between Audi and Peugeot was startling. Audi had a big problem with the pick up going off line to pass the slower cars, to the extent that Benoit Treluyer had a hole punched through the wheel arch of his car, and the Peugeot was simply better in the second stint on the same set of medium compound tyres. As a result, Audi went away to re-think its strategy.
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