July 15, 2006
Tooele, Utah IMSA today published a bulletin that affects the refueling rig restrictor of the diesel cars participating in the American Le Mans Series, specifically the Audi R10 TDI cars. The change limits the refueling restrictor from the current 38mm permitted under the regulations to 33mm, effective immediately.
“As was highlighted in today’s press bulletin issued by the ACO, there is an overall desire by the organizing bodies to work toward a situation where all cars, no matter what fuel they choose to use, have the same amount of energy on board,” said Tim Mayer, Chief Operating Officer of IMSA. “However, that is not the situation with the current regulations. So as an interim step, we have restricted the R10 so that it cannot receive more energy in the tank in a given time frame.
“We notified the team of this change at the Lime Rock Park event. However, because of a variety of test and calculation methods that are possible to determine the energy content of fuels, we chose to hold the public release of the bulletin until we had verification of the numbers,” added Mayer.
The current regulations permit the same 90-liter tank on both diesel and gasoline cars but permit the larger restrictor on the refueling rig of diesel cars because of the different viscosities of the fuel.
“The original intent was to permit the full volume of the tanks to be filled in the same time,” said Mayer. “However, diesel is a more energy-rich fuel for any given volume. The change that we have implemented means that the energy delivered will be similar, for the diesel versus gasoline, for the same length of refueling. The goal is to ensure that competitors have the opportunity to compete without a quirk in the physics of the fuels creating a particular advantage. We are currently working with the ACO to come up with a formula for tank sizes for a variety of different fuels.”