A Diesel Wins at Le Mans
A Diesel Wins at Le Mans
(OP)
Well, it looks like my original question from thread108-64541 has been answered; An Audi R10 car with a V12 5.5L turbo diesel convincingly won the 2006 Le Mans 24 hour race:
htt p://www.le mans.org/2 4heuresdum ans/live/p ages/chron os_gb.html
The second team car had a number of problems, and came in third. Now the question is: how many other racing classes will diesels be competitive in? I note that PSA are preparing a V12 diesel to compete with the Audi, and now JCB are preparing a diesel world land speed record car using their 4.4L industrial diesel engine!
PJGD
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The second team car had a number of problems, and came in third. Now the question is: how many other racing classes will diesels be competitive in? I note that PSA are preparing a V12 diesel to compete with the Audi, and now JCB are preparing a diesel world land speed record car using their 4.4L industrial diesel engine!
PJGD





RE: A Diesel Wins at Le Mans
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: A Diesel Wins at Le Mans
I must admit I've always found mixed-rules racing a little difficult to take seriously. The rule makers try to jiggle with details in the rules to level the playing field, but there's always one clear best package. Take the dominance of Ducati in the 90s WSB. They had a bigger engine and less weight. And the two strokes in MotoGP when engines had to be the same size (500cc).
RE: A Diesel Wins at Le Mans
Special rules are just as often made for marketing, smog, and popularity as they are to level the playing field.
2-strokes really got hammered for marketing and smog. They have to race against 4's nearly twice their size.
RE: A Diesel Wins at Le Mans
These days yes, in the 80'2/90's no. And that reinforces my point (and Greg's). In a mixed field the winners are determined by the rules. Remember the oval piston "v8" NR500 that Honda made to try to get even with the strokers?
RE: A Diesel Wins at Le Mans
I am not familiar with the specifics of the rule change, but any views on how significant it was to this race? Who would have won if the rules had not been changed, and by how much?
PJGD
RE: A Diesel Wins at Le Mans
These cars are going around in circles! Their efficiency in real-world terms is zero.
RE: A Diesel Wins at Le Mans
I don't know what the rules are now or what they were in the past, but a quick look at the website gave me this file.
http://ww
Just glancing at a couple of sections (and maybe taking them out of context) gives me the impression you could race say (examples)
a 4 litre gasoline engine with more than two valves per cylinder and about 1/2 an atmosphere of boost,
or
a 5 1/2 litre diesel engine with nearly 2 atmospheres of boost.
RE: A Diesel Wins at Le Mans
The rules also state that the fuel tank must be no more than 90l in size, regardless of what's in it. Gasoline and diesel have similar lower heats of combustion based on mass (within 1%), but diesel is about 11% denser. So a full tank of diesel contains slightly more than 10% more energy than a full tank of gasoline. That's a bit of a head start in endurance racing - at least 10% less pit stops.
RE: A Diesel Wins at Le Mans
The Judd has a rated speed of about 8K vs 5K rev/min for the Audi.
As for fuel efficiency, well yes, the Judd had to make 29 fueling stops as against 25 for the winning Audi. Obviously, the fewer the stops, the better.
PJGD
RE: A Diesel Wins at Le Mans
Another rule exception the Audis got was that they were allowed a larger diameter restrictor (38mm for diesel vs 33 for gasoline) on their fuel filling rig because diesel flows slower than gasoline, and the ACO didn't think they should have slower pit stops than everyone else just because they're using a different fuel.
Granted, this is the first year for a diesel endurance racer so the ACO can't be expected to have the rules perfect yet to equalize the competition, but it certainly seems like they tried to give plenty of help to diesels to make up for their shortfalls, but didn't give them any restrictions to lessen their natural advantages.
Bob
RE: A Diesel Wins at Le Mans
PJGD