Diesels finish 1,2,3 again at 24 Hours of Le Mans!
by Sam Abuelsamid on Jun 15th 2009 at 8:42AM 
At this weekend's 24 Hours of Le Mans, the Peugeot 908 HDi finally broke Audi's decade long stranglehold on the endurance classic. For the past two years, Peugeot had clearly had the speed advantage over the Audi R10 TDI but the team failed to keep the cars running reliably enough to beat the more reliable and fuel-efficient Germans. This year, Audi - expecting Peugeot to up their game - introduced an all-new and faster car, the R15 TDI that won at Sebring in March. Unfortunately, the R15 hasn't run in a race since then, and when they arrived in France they didn't have either the speed of the Peugeots or the trouble-free run of past years. One of the three Audi's crashed early in the race while the others both had difficulties during the remaining 24 hours. The #9 908 of Marc Gene, David Brabham & Alexander Wurz ran largely trouble free all day and night to take the victory a lap ahead of the #8 Peugeot of Sébastien Bourdais, Franck Montagny & Stéphane Sarrazin. The lone competitive Audi of last years winners, McNish, Capello and Kristensen was 6 laps down in third place. The third Peugeot finished 6th overall and followed its sister cars across the line on Sunday afternoon.
Reader Comments (Page 1 of 1)
jharlan 10:03AM (6/15/2009)
Diesels again. I love it! It's just hard to beat superior technology.
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Ian 2:11PM (6/15/2009)
The ACO made the rules to firmly advantage diesels some years ago and the tweaks have yet to dent that massive advantage.
Summary: The ACO get what they want.
If Ferrari show interest in returning to the LMP1 category they would only do so using regular gasoline so they would insist upon a more level race track.
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downtoearth 12:07PM (6/15/2009)
There are two dirty little secrets about why diesels win in Le Mans. Sam, why don't you write about them?
1. Diesels are given unfair weight advantage.
This is the Le Mans prototypes specification regulation paper:
http://www.lemans.org/sport/sport/reglements/ressources/2009/auto/reglement_lmp_2009.pdf
Now when we look at the page 9 article 4, there is no differenation in weight between gasoline and diesel cars.
Diesel cars are always heavier than comparable gasoline ones due to necessary larger displacement engines, heavier engine blocks (to sustain higher compression), heavier clutches and gearboxes (diesels transfer given power at lower revs so driveline needs to sustain higher torques, hence added weight) and additional components like particulate filters.
Yet the regulation enforces gasoline cars to abandon their weight advantage (a crucial aspect in racing) and carry a BALLAST to comply with minimum weight.
Sadly, engineers of gasoline cars cannot get rid of the ballast and turn the weight to spare into larger displacement and more power because... as you can see at the page 10 article 5, the displacement is strictly limited :-)
This is how you do it. Create a biased regulation and you have diesel cars winning races. Simple.
2. In the LM P1 class there are virtually no contenders except diesels. No significant large budget team races there. So basically, rich factory teams racing diesels compete with nobody, with ghosts. It's easy to win when a similarly stong contender is simply absent.
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ale 12:13PM (6/15/2009)
while I love that diesels are winning, its an old story... Id like to see Audi get their stuff together next year and see some diesels in GT2... i think there, some progress can be made...
i want peugoet and audi to keep racing diesel, that technology improves diesels sold on the street, but id like to see diesel power expanded and do more...
jharlan 12:35PM (6/15/2009)
Aren't the rules the same for all cars in a particular class? I don't understand the whining. The innovations in diesel tech benefit all, and have forced innovations in gasoline technology to be able to compete. Most breakthroughs come off the race track.
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wxman 1:14PM (6/15/2009)
>1. Diesels are given unfair weight advantage.<
And petrol LMP1 cars are given an unfair fuel capacity advantage. See Page 13, Article 6.5 of the link you provided. Petrol fuel tanks are 90 liters, diesel fuel tanks are 81 liters. Why should diesels be penalized just because the fuel inherently has more energy per unit volume than gasoline?
Besides, the weight issue was tried years ago (2006) and the diesels still beat the gassers (the petrol cars were allowed to be 65 kg lighter than the diesels AND the gassers also had a fuel capacity advantage - see http://www.paddocktalk.com/news/html/modules.php?op=modload&name=News&file=article&sid=39173 ). The Audi R10s finished 1-2 at Road America that year and the fastest R10 TDI beat the fastest Dyson Lola in qualifying by over 2 seconds.
>2. In the LM P1 class there are virtually no contenders except diesels.<
There were 19 entries in LMP1 for this year's Lemans race and 10 of them were petrol. How does that equate to "virtually no contenders"?
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why not the LS2LS7? 4:25PM (6/15/2009)
No, the question is why should Diesels not have the same amount of energy in their tank just because it would require a smaller tank. Ethanol cars are given more fuel because it has less energy, why should Diesels not get less? The point of limiting tank size is so that cars take an approximately equivalent number of pit stops, Diesel should be no exception.
You don't know what you're talking about vis-a-vis 2006, the R10 got the same size fuel cell as the gas cars and the gas and Diesels were speced at the same weight, the minimum weight on an LMP1 car was raised because the R10 couldn't make the minimum. The R10 was still 10kg over minimum. When the minimum weight was restored in LMP1 later, the R10 could not keep up with the lighter gas cars on the road courses.
http://en.wikipedia.org/wiki/Audi_R10#Weight
wxman 6:26PM (6/15/2009)
>You don't know what you're talking about vis-a-vis 2006<
Did you even look at the link I provided? I'm just reiterating what the article said...
"...At Road America the LM P1 Lolas entered by the Dyson team can race with 65 kilograms less than the Audi R10 TDI. Furthermore, from the following race at Mosport, the Dyson Lolas will be granted a five-litre larger fuel tank...."
Maybe they don't know what they're talking about but I do recall they changed the rules late in the 2006 ALMS season (i.e., just before the "Road America" race in Wisconsin) because the R10s were so dominant up til then.
why not the LS2LS7? 7:11PM (6/15/2009)
You are stating American Le Mans (ALMS) rules, not Le Mans rules. ALMS is run by IMSA, not the ACO, and they at times differ. Sometimes they even fight a bit.
IMSA was looking for more competition for the overall win, so they gave some LMP1 cars leeway to race with less weight in hopes they could compete for the overall win against the Diesels. And it worked to a limited extent. The ACO did not bend and at Le Mans gas cars still ran at the higher weight.
Also, the larger gas tank you quote was before the R10 was lowered to 81 liters. So the gas cars were running 95L (IIRC) versus the 90L of the R10. The next year, both ACO and IMSA went to 81L for Diesel, and IMSA returned the gas cars to 90L. Note that even at 81L the Diesels still have an energy advantage (not disadvantage) with their tank.
2006 is a great example of why the fuel cell size was an issue. At Le Mans the R10s were going 14 laps on a tank, while the gas cars went 11 or 12. And it was quite likely Audi was sandbagging. If you stop your car for 2 minutes 30% more often than your competitor, you're going to lose, period.
I don't recall the changes you speak of later in the 2006 IMSA season, but I know IMSA was trying things to try to let non-Diesels compete for the overall win. The ACO doesn't care if Le Mans is a runaway. It's only once a year and it's so prestigious that manufacturers line up to show up. But you won't have enough teams showing up for the entire ALMS season if they know they can't even make a good showing.
Ian 2:18PM (6/15/2009)
So the Aston Martin Lola multiple team effort wasn't a serious professional attempt?
So the Pescarola petrol engined cars were not run by professionals?
CLEARLY the present rules STILL favor diesel engines over petrol engines and by a WIDE margin. Diesels ran away with qualifying and were all some 5+ seconds a lap faster than the best petrol engine.
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Jospeh 2:52PM (6/15/2009)
The diesels are turbo charged I believe, are the gasoline cars equipped with turbo's? I don't think so.... thought this is not allowed for gasoline cars. Take the turbo's off the diesel cars and they lose 40% of their power....
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why not the LS2LS7? 4:54PM (6/15/2009)
The ACO allows turbochargers on gas engines up to 4.0L, although the boost is heavily restricted (1.5bar at 4.0L, 1.58bar at 3.6L). The 5.5L R10/R15/908 FAP are allowed 2.75bar of boost (down from 3.00bar last year), almost quadrupling the effective displacement of the already large Diesel engines. The largest gas engine that is allowed 2.75bar of boost is 2.2L*.
A turbocharged gas engine uses 32.9mm restrictors (assuming a two bank config), for a (0.00170m^2 total cross section) (slightly more for a closed top car). The R10/R15 gets two 37.9mm restrictors (0.00225m^2 total cross section), the 908 FAP gets two 38.3mm restrictors (0.00230m^2 total cross section). So the Diesel is breathing through a 35% larger straw.
The largest normally aspirated open top gas engine allowed (used in the Zyteks I believe) is 6L and gets two 32.5mm restrictors, total cross section (0.00165m^2 total cross section). The Diesel gets a 38% larger restrictor than this car.
The asterisk above applies to all gas engines. There are slightly looser regs for 2V/cylinder pushrod gas motors. I ignored these in all calculations because there are no pushrod LMPs right now and there won't be any time soon as the regs aren't favorable enough to overcome the lower revs developed by a pushrod motor in an LMP.
Marshall 4:34PM (6/15/2009)
As a diesel Golf driver it's understandable why gasoline powered LeMans cars are losing. My TDI is my first diesel and I'll never go back to a low torque, low efficiency, low fun gasser again!
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