Smaller fuel tanks for diesel cars

The race's organisers, the Automobile Club de l'Ouest, have completed initial studies on the performance of the different categories in this year's race and concluded that the rules for diesel-powered cars give them an advantage when compared with petrol equivalents.

They deduced that the Audi R10 TDI lapped on average 3.2 seconds quicker than the Pescarolo Sport cars, the leading petrol entry.

The new R10 dominated this year's race, leading Henri Pescarolo to slam the technical regulations that he believed favoured diesel-powered cars.

In an attempt to redress this balance, the ACO will now mandate a smaller fuel tank for diesel cars.

"Concerning consumption, the tank capacity will have to be adjusted in such a way that the cars receive the same quantity of energy at each refuelling stop," said an official statement.

The R10s were able to last two to three laps longer between pitstops than the fastest Pescarolo sport cars, meaning they had to spend less time over the 24 hours in the pits, seen as a key advantage.

The final changes in rules for next year will be announced in September in consultation with the International Motor Sports Association, sanctioning body of the American Le Mans Series.

However, after their initial findings, the ACO is not likely to introduce anymore technical changes for diesel-powered cars, because they believe it was impossible to tell whether it was the engine or a new and better chassis that gave the R10 its extra pace.

"Starting from a blank page, and without any help whatsoever, (there being no such thing as a diesel engine in racing cars), we had to lay down the basis of a rule system acceptable to all the entrants," continued the statement.

"When considering this difference, we must take into account the improvements in performance which are linked to the chassis, the suspension, the aerodynamics, and of course to the engine.

"Only the advantage linked to the engine performance can lead us to take steps to reduce its performance, since all the other elements of the car are constructed according to the same specifications. It is therefore up to the manufacturer to produce the best car."

Peugeot will join Audi with a diesel-powered prototype at next year's race.