This year's 24 Hours of Le Mans was shaping up to be a second straight flag-to-flag romp for the Peugeot 908 diesels, right up to the point where they all started dropping like flies. Needless to say, the Peugeot Sport engineers have taken a long, hard look at why all four cars failed to finish – and in the case of three of them, it basically comes down to perfect race conditions leading them to be running too fast.
The first car to go out was the #3 entrant that was built up from the tub that won the 2009 race. After two-and-a-half hours of racing, a suspension mounting point separated from the carbon fiber tub as the result of an undetected structural problem.
The other three cars all went out later in the race with what turned out to be an identical connecting rod failure. A combination of circumstances led to all of the cars running faster this year and putting increased stress on their engines. Not mentioned by Peugeot in its report is the fact that the new Audi R15+ ran considerably faster in 2010, pushing the Peugeots to the limit. At the same time, cool temperatures and a grippy track, blended with air-to-air intercoolers that didn't clog up as much as they did in the past led to more air going into the combustion chamber. More air means more power and an increased load on the pistons – especially late in the race. No doubt Peugeot will be looking to increase its safety margins as the engineers prepare their all-new 2011 challenger.
Three weeks after the 2010 Le Mans 24 Hours, and after inspecting the cars that contested this year's event, Peugeot Sport looks back at the problems that affected the 908 HDi FAPs in the French race and provides details of its plans for its Intercontinental Le Mans Cup programme during the second half of the season.
Looking back to the 2010 Le Mans 24 Hours
Bruno Famin (Technical Director, Peugeot Sport): "To begin with, with regard to the N°3 908 HDi FAP which retired 2½ hours into the race, we have found a quality-related problem concerning the production of the tub at the point where the lower front-right suspension wishbone is attached to the chassis. This is the same tub that won the 2009 Le Mans 24 Hours and the 2010 1,000km de Spa-Francorchamps, and – like every 908 chassis – is regularly inspected at the factory using sophisticated tools that enable us to detect ageing or damage to the carbon. The problem in this case, however, was due to a totally undetectable defect which resulted in a premature and sudden failure of the mounting point.
As far as the engines are concerned, it didn't take us long to confirm that all three engines suffered the same problem, i.e. conrod failure, although the cylinders that were affected were different. Further investigation has just revealed that the particularly severe conditions encountered at Le Mans in June led to excessive overload of the V12s in question.
Indeed, the track benefited from high levels of grip this year, so the engines spent longer at full throttle than we expected. At the same time, the weather stayed cool and, unlike previous years, the air/air intercoolers did not become clogged up. The filling of the combustion chambers remained extremely efficient throughout, which in turn meant that the performance delivered by the engines was particularly high. Okay, the conditions were the same for all competitors, but we were running new conrods this year. That said, they had undergone thorough testing on the bench and during the numerous on-track simulations we carried out upstream of the race.
We didn't observe the slightest problem with them during any of these test sessions, so there was nothing to suggest that we were closer to the limit than we had imagined. As it turned out, the race conditions tipped us to the wrong side of that limit. Having contested the Le Mans 24 Hours three times, we had every faith in our processes. The evidence now points to the fact that this wasn't the case and that despite our growing experience, it is very difficult to master absolutely everything. The conditions we face at Le Mans differ every year, as do the constraints to which the cars are subjected. It is clear that we need to reinforce our validation procedures."
The second half of the season: the 2010 Intercontinental Le Mans Cup
Peugeot Sport's programme for the second part of the season will focus on the team's participation in the Intercontinental Le Mans Cup. Either one or two cars will take part in the three races that make up this series and Peugeot Sport's Director Olivier Quesnel has divided up the 'drives' amongst Team Peugeot Total's nine drivers as equally as possible: