Audi R10 TDI Wins Le Mans 24 Hour Race

It was not clear in the story, are the fuel tanks limited by volume or weight of fuel. Diesel fuel weighs more than gas (petrol) by volume. BTU's per pound for diesel and gas are close, but BTU's per gallon gives a big advantage to the diesel powered car.

Diesel has more energy by volume then gasoline. Gasoline has less density, 6.34 lbs/gal versus 7.01 lbs/gal for diesel. That's what happens w/ additional refining. The fuel tanks for Prototype 1 & 2 cars is 90 liters (23.78 gals.). The Audi is a Prototype 1 class car w/ a minimum weight of 925 kg (2,040 lbs.) The advantage to the diesel powered Audi comes from many factors. The type of engine, fuel and the money that was needed to develope it. The Audi R10 is only 200 days old from the time its wheels first touched the ground. The main factor to the R10 success is the KNOWLEDGE gained in developing the R10's predecessor, the R8, which was gasoline powered. Don't read anything into that fact. Any type of motorsport, but especially endurance roadracing, must have an incredible amount of attention to detail, race preperation and component reliability. The sister car to the winning Audi came in third because of mechanical gremlins. The diesel's viability in todays cars come's from the advances in electronics and computers. The engine has always been a viable alternative source of power but only to a limited extent, till now. It's not a silver bullet. Hybrid (electric or hydraulic), E85 ethonal and even an all electric car will have a place in our future commute and transportation needs.

The diesel powered car can carry over 10% more fuel by weight for the same size gas tank. A significant advantage. Maybe they should limit the size of the fuel tank to keep the weight of the fuel the same. However that would really shortchange an E85 car.

I don't see your point. The diesel has its fuel delivered dy direct-injection, that is the big advantage. Gasoline engines use indirect-injection, although VW is selling the 2.0L turbo engine in their GTI and Jetta models w/ the injectors in the combustion chamber, ie direct-injection. As I stated, there were many factors in the Audi's win. Preparation, engineering, MONEY and racing luck.

My point is that the rules seem to permit a diesel powered car to carry more fuel (by weight), therefore it loses less time refueling. I had glanced at an MSN article about the race and don't remember the exact numbers, but I think the diesel cars were getting about 15% better mpg. If you go by fuel weight, the advantage would shrink to maybe 5%.

The technology that can utilize this type of energy, ie fuel as opposed to gasoline, has not recieved any performance restrictions by a race organizing body. 90 liters for all P1 & P2 competitors. I understand your point. It's the kind of technology the diesel is that gives it an advantage, it's not just the energy source. If any restrictions are applied to Audi, it will come for the 2007 season. However there will be Peugeot entering a diesel powered P1 car at that time. We'll see how that plays out. It may also turn out that instead of restricting the diesel powered cars there may be less restriction on the gasoline cars instead.