Speculation has been growing in recent weeks that the result of the 2015 Le Mans 24 Hours was decided at least in part by fuel flow metering rather than the out right speed of the Audi R18 and Porsche 919. During the race the challenge from Audi, the pre race favourites, faded for no clear reason.

Porsche LMP Technical Director Alex Hitzinger spoke to Racecar Engineering following the race and revealed that he too was not clear why the Audi’s faded.

“The biggest surprise for me was that the Audi was slow. I expected them to be much faster during the night, and I don’t know why they were not. The engine performance gets better in the cooler temperatures” he explains in the August edition of Racecar Engineering magazine.

But even during the race Paul Truswell of Radio Le Mans identified the loss in pace of the R18’s and was contacted by well known engineer Howden Haynes who speculated that the loss in pace may relate to the fuel flow meters used on the R18’s. Indeed this has happened before at Spa in 2014 the Le Mans spec Audi R18 was slow, and the fuel flow meter readings were blamed in the cool temperatures.

At Le Mans in 2015, it seems that the team, the only one to be running a diesel engine and running with particularly hot sensors, experienced a similar occurrence but it impacted all three cars.

Paul Truswell and Andrew Cotton have investigated the real reasons behind the result at Le Mans this year and have published their findings in the August 2015 edition of Racecar Engineering.



Meanwhile following Le Mans a new fuel flow meter was homologated for use in LMP1 and Formula 1 by British company Sentronics (part owned by Reventec). While the sensor has yet to be used in competition in either category it has been tested extensively both on track and on the dynos at the FIA test house Calibra technology in Cambridge, England.

Teams in both LMP1 and Formula 1 will now have a free choice of two different sensors.