Audi LMP1 Discussion

[hcl123]

Originally Posted by Bentley03

Audi were unable to match Porsche in cooler conditions, was it just tyres or was it something else. Audi did 'something' to the car when Lotterer handed over to Treluyer which improved the car's pace. Bodywork issues, Audi had them, Porsche did not. I would list these things under 'preparation', or lack of.

I hear and see all the arguments regarding pace, the 'what ifs', the 'yes buts', but ultimately, a clean run from a Porsche was enough to undo Audi, because of things which I would file under 'not prepared'.

I don't buy this 'unprepared story' a bit, if there is race traditionally they prepare the most is Le Mans... only this year was not to be Audi's year (call it ghosts, bad luck, whatever, and perhaps human error in bad tires choices by more than 1 set change is at play, or perhaps they didn't have tires for unexpected daylight winter like temperatures and moister at night, and had to adapt, and this human error and or adapting is part of the race)... again... no team can win always.

[hcl123]

opps! repeat

[hcl123]

Originally Posted by GasperG

I said it numerous times, weight, weight, weight, with low revs you can not avoid being over weight be it gasoline or diesel, both will gain efficiency with weight, making a race car less efficient and slower. Why not race with a coal power plant it's 45% efficient, why not gas turbine power plant it's 60% efficient?

And I think by the rules petrol engine must be spark ignition, is rotary engine allowed? When compression ignitoin gasoline engine comes (to meet half way with diesel) they will once again have to adjust the rules, that is how this works, rules are always adjusting to make racing competitive

I will say it once again it's not efficiency racing it's endurance racing with power restrictions through fuel flow.

FIA/ACO says its an "efficiency formula" adapted to endurance racing (who is more efficient has an advantage)...

And exactly the part i contest is this 'fuel allocation' management for the 'equivalence of performances', that apply only to diesel compared with petrol... which is clearly biased against diesel, at least energetic content per lap is almost 17% lower for diesel, which by itself doesn't imply efficiency at all (Audi is only there because they forcibly had to be that much more efficient and are, other possible diesel contenders might not be so good) and goes against the spirit of the rules because it doen's restrict likewise petrol turbo techs, compression ignition etc against other petrol techs... you only have restrictions if you are diesel, though engine rules are open to all, they could be much more open (avoid possible complains against engines)...

The fair would be spark ignition, microwave or compression ignition etc, would run with exactly the same energetic content per lap, so fuel flows allowance would be calculated attending the energetic content of the fuel, which would be inspected and enforced...

*If* rules were like this, you could even have LNG cars(perhaps not cause of safety concerns), what ignition process whatever engine (inside some rules) doesn't matter, and rules could be the same for many many more years independent of what contender brings what engine tech.

Weight is a pretty obvious way of 'performance equivalence'... leave the engine alone... is not applied that way because perhaps some gentleman with decision making power doesn't sleep thinking diesel techs due to their much more torque abilities could walk allover weight increases as if they were not indicating in the scales (FEAR and PREJUDICES are terrible flaws)...

[cokata]

Originally Posted by GasperG

I said it numerous times, weight, weight, weight, with low revs you can not avoid being over weight be it gasoline or diesel, both will gain efficiency with weight, making a race car less efficient and slower. Why not race with a coal power plant it's 45% efficient, why not gas turbine power plant it's 60% efficient?

And I think by the rules petrol engine must be spark ignition, is rotary engine allowed? When compression ignitoin gasoline engine comes (to meet half way with diesel) they will once again have to adjust the rules, that is how this works, rules are always adjusting to make racing competitive

I will say it once again it's not efficiency racing it's endurance racing with power restrictions through fuel flow.

What i have been saying for some time now. Diesel is more efficient - great, but it is also substantially heavier then a Petrol equivalent. And more weight is the one thing that you want to avoid for both efficiency and performance.

[hcl123]

Thicker engine walls and covers don't imply nothing of efficiency, and the moving parts being substantially more heavy in diesel than in petrol is a urban myth... the are indeed heavier because have to be more resistant, but substantial is a myth (small urban utilitaries 'minis' can have up to 2L diesel engines)...

This same argument and similar were repeated 'ad obnoxium' upon the bigger V12 diesels, Audi itself said, IIRC, that their engine was 20kg heavier compared with an equivalent V12 petrol(5.5L bi-turbo)... and since most of the diff is in the moving parts, the less the cylinder number, the shorter the crankshaft, the less the difference... which upon a V6 might very well be inside the single digit number(kind of irrelevant).

[chernaudi]

I wonder what issues that Pruett is referring to by saying that Audi rarely made it much past 12 hours in their 30 hour tests without a garage visit/repair that took longer than a normal pit stop.

After all, Audi did a 30 hour test at Sebring with no major issues, but that was with the sprint spec car.

Sort of sounds as if the LM spec R18s had the bending/breaking engine cover issue all along possibly. And Audi weren't able to come up even with a jury-rigged fix for it like last year when the front floors were breaking off on curbs.

And I've been wondering if the issue wasn't with the engine covers' own durability in and of itself alone. I didn't like the tall rear fender leading edges at first, simply because they looked awkward. Now though, I wonder if they were influencing the aero and causing the rear fenders to twist/bend, and being the main factor in the problem.

You do have to remember that in head-on shots, the rear fenders LE's were taller than the highest point of the front fenders.

[chernaudi]

Detail shots and HQ press photos here--also includes interior photos:

http://fourtitude.com/galleries/?c=s...attro%2FPhotos

At some point, I'll probably post this link again if the writers/photographers from Fourtitude go to COTA, especially if Audi run the sprint bodywork there.

Interior teaser shot:

[Ephaeton]

Isn't it absurd that nowadays professional photographers make photographs that look more like renders than real photographs? This one, even after magnifying, looked more like a screenshot from a current-gen racing game to me than the real thing.

[Akrapovic]

There's a lot of photoshopping in it, that's for sure.

[hcl123]

Originally Posted by chernaudi

I wonder what issues that Pruett is referring to by saying that Audi rarely made it much past 12 hours in their 30 hour tests without a garage visit/repair that took longer than a normal pit stop.

After all, Audi did a 30 hour test at Sebring with no major issues, but that was with the sprint spec car.

Sort of sounds as if the LM spec R18s had the bending/breaking engine cover issue all along possibly. And Audi weren't able to come up even with a jury-rigged fix for it like last year when the front floors were breaking off on curbs.

And I've been wondering if the issue wasn't with the engine covers' own durability in and of itself alone. I didn't like the tall rear fender leading edges at first, simply because they looked awkward. Now though, I wonder if they were influencing the aero and causing the rear fenders to twist/bend, and being the main factor in the problem.

You do have to remember that in head-on shots, the rear fenders LE's were taller than the highest point of the front fenders.

Neither #8 #9 had any problems with covers... and #8 had an accident, fixed in 4 minutes, that if were another car most likely had stayed on the spot and retired, which attests the strength of the all car (way it impacted with rails was lucky, though).

A tiny micro-crack is enough for with racing time beating the car, resulting in what resulted to #7, most likely an origin defect in that piece, very hard to detect, that almost never passes upon quality checks(all it takes once, for bad results).

Was unfortunate yes... but it is no good starting to chase scape goats... every year we see cars losing entire wheels all of a sudden, part that requires immensely more rigorous tests and quality checks... in short, sh*t happens, this year it happened to #7... as a 'cliché' often used; 'that's racing'...

About the 'taller' rear fenders i'm very positive its a more efficient aero shape... the all bodywork was tunned that way, even the rear view mirrors disappeared into the bodywork for the same effects... taller rear fenders had nothing to do with happen to #7.

[bobec]

Originally Posted by chernaudi

In the briefing all drivers were told that if there was an issue of difference between the light boxes and the corner workers' flags, the corner workers' flags should take precedent.

That's what Loic was going by, and ironically he got bit by basically doing what the race director said was the right thing to do.

Granted, it'd been better if the light vs flag faux paux didn't happen, but it seemed like there was a line of pro-am drivers slowing down and causing a traffic jam, with some pros who wanted to heed the advice given by race control left with no other choice but to pile in and make things worse.

Yes, exactly. Why isn't anyone getting penalized? Does someone need to die first? Amateurs shouldn't be allowed to get away with messing with safety and the race outcome.

For me the Aston on the right of the track is most to blame. Not only is he not obeying the directions from the briefing, he is single-handedly blocking half the track, with the left half being blocked by a line of GT cars.

And did Fisichella (presume it was him in the 458) have to be so aggressive in his overtaking move and take so much room? Duval was almost making it. Did Fisichella even check his mirrors.....

[Starfish Primer]

Originally Posted by hcl123

Neither #8 #9 had any problems with covers... and #8 had an accident, fixed in 4 minutes, that if were another car most likely had stayed on the spot and retired, which attests the strength of the all car (way it impacted with rails was lucky, though).

A tiny micro-crack is enough for with racing time beating the car, resulting in what resulted to #7, most likely an origin defect in that piece, very hard to detect, that almost never passes upon quality checks(all it takes once, for bad results).

Was unfortunate yes... but it is no good starting to chase scape goats... every year we see cars losing entire wheels all of a sudden, part that requires immensely more rigorous tests and quality checks... in short, sh*t happens, this year it happened to #7... as a 'cliché' often used; 'that's racing'...

About the 'taller' rear fenders i'm very positive its a more efficient aero shape... the all bodywork was tunned that way, even the rear view mirrors disappeared into the bodywork for the same effects... taller rear fenders had nothing to do with happen to #7.

One comment on the #7. At the start I was at the grandstand exactly in front of the #7, when the cars were serviced before the rolling start many mechanics were still working on the rear left side and looked a bit nervous.

[Victor_RO]

Sam Collins told us at the Ten-Tenths meeting that the Audis were in quite serious technical issues between warm-up and the race; his comments were at around 11:30-12:00 (about 3 hrs before the race), and he mentioned that he had come straight from the pitlane and he saw the Audis in bits in the garage.

[chernaudi]

Audi Sport before the race said that the #7 had a coolant leak. Could easily explain Sam's observations--one car for sure had the problem, and the others were examined to make sure they didn't have a similar problem.

Could it be an issue with the LM spec cooling system (reportedly a bit different than the sprint spec version)? A bit strange, though, since Audi didn't seem to have the issue at Spa with nearly identical cars and presumably identical cooling systems.

[Articus]

A coolant leak is just that, a coolant leak. I wouldn't read too much into it. Just sounds like a slip up in vehicle assembly and leaking somewhere deep in the engine bay.It's not like the designers put holes in the lines without anyone noticing.

Timing was poor so naturally everyone is worried.

[chernaudi]

Marshall Pruett was the guy who got the ball rolling by stating that he heard that Audi hadn't made much past half way in their 30 hour tests with the LM spec car without some issue that caused a significant delay.

Granted, he didn't disclose if it was early occurrences of the bodywork issues that plauged Audi in the last third of the race at LM, or the cars had cooling issues, or whatever the problem he was made aware of was.

Fact is this: Audi ran a 2015 sprint race spec car at Sebring for a 30 hour test and it didn't have any significant issues. Audi ran the LM spec cars at Spa with no reports of issues beyond the #8's ECU issue during the race.

What ever the issue is that Marshall found out that had the Audi guys a bit concerned at LM seems/seemed to be unique to the LM spec package, and the problems didn't show up in early tests or at Spa or Monza. They showed in the last 1 or 2 30 hour pre-LM endurance tests, and they might have showed up in someway during the LM race week.

[Bentley03]

What intrigues me most is the inability of the Audi's to match the pace of the Porsche's in cooler conditions. It was not that cold overnight this year, yet the Porsche's were able to put in the sort of stints you would expect during the night at Le Mans, and the Audi's were not. Maybe it was just a tyre issue, maybe, but my gut feeling is that there was something else contributing to their lack of performance. And maybe this '12 hours before hitting problems' is related to running at cooler temperatures during the 24 hour tests, it would make some sort of sense (assuming the test starts in warm conditions and conditions are cooler 12 hours in). But maybe that's me putting 2 and 2 together and coming up with 'wrong!'. And surely Audi would have tested different tyre compounds in cooler conditions, and would have been aware of any drop off in performance on certain compounds, thus being prepared for the overnight stints at Le Mans. Same tyre supplier, Porsche maintained their performance, Audi did not. I know it's impossible to replicate Le Mans at night in testing, but, really, just a tyre issue?

[chernaudi]

That was a performance issue with not being able to make the tires work at night they way that that they wanted them to. I don't think it was a flaw in the car itself, just a flaw in set up or Audi guessed wrong when they asked Michelin to concoct the tires that they wanted for LM.

Doesn't really explain the bodywork issues or the glitches that Marshall was hinting at. Those by far were a much bigger problem. And so far, there's been no definite explanation for the issues aside from the fact that Audi knew of some issues and they were trying to work around them. All we can do is speculate until we find out for sure what had the Audi Sport guys sort of scratching their heads with car issues.

Only things that seem clear is that the sprint spec cars haven't had very many issues in racing or testing what so ever, and the issues seem to be confined to the LM spec machines.

Of course, the fact that Audi didn't have any major issues early in testing or at Spa during the whole race weekend aside from the #8's ECU failure does muddy things up.

It's certainly not clear why the issues seemed to suddenly pop up so close to LM time that Audi sort of had to hope for the best and prepare for the worst, and according to Pruett, Audi team members did seem to admit to him off the record that all things considered, they got out of LM relatively scot-free.

But it might be a bit telling that the #7 Audi had a coolant leak and Audi Sport were examining the other cars. This was just a few hours before the race, and it might have been a fluke occurrence. Still, it seems that circumstances might add up.

[Artur]

About the tires being the possible explanation for Audi not performing as expected, at night, I guess that maybe can be related to the restriction that was imposed this year.

Previously, there was no limits regarding tire sets for the race. This year, ACO came up with a 12 sets limit for the race(FP/QLFs not included, nor any kind of wet weather tire). I don't know how that worked out, ie, did they have to choose the compounds before the race(ie, 8 Mediums, 2 Softs, 2 Hards) or could they select the compounds as the race was unfolding?

As far as I know(I can be wrong), rules allowed for 3 different dry compounds in previous years(don't know the situation for 2015). Michelin brough one more conservative one which we could refer to as Hard, then there was the compound expected to be the one suited for most part of the race(we could call it Medium) and finally there was a softer compound made to work on the cooler conditions of the night

Maybe, depending how the tire rules were, Porsche had the softer compounds choosen so that they could use during the night, while Audi could've made a choice mistake and ended up without the softer tire to use during the night?

[Artur]

Forget all I wrote there, I just checked Michelin's PR and everybody used the same single compound for the entire race.

All the LM P1 manufacturer teams used a single type of tire for the 2015 Le Mans 24 Hours: namely the MICHELIN 'soft hot weather' slick, which is designed to give its best at temperatures ranging from 18°C to 40°C.

http://www.michelin.com/eng/media-ro...-Hours-victory

Now I guess Porsche has a more aggressive suspension setup which puts more heat into the tires, which will make them wear more during the day(Audi and Toyota were quadruple stinting all the way through, while Porsche was tripple stinting) but will put them in more optimal temperatures during the night, providing more grip.

Quite surprising that everybody just used one compound for the entire race, though.

[chernaudi]

Anyone think that yet another Audi R18 headlight cluster redesign is underway considering that the new A4 was launched Monday morning?

[tomazy]

Reading about the new A4, there is an interesting statistic regarding the 272hp, 3.0 TDI six-cylinder engine.

The three-liter diesel engine, which weighs only 190 kilograms..

I wonder how much lighter the engine in the R18 is.

http://fourtitude.com/news/Audi_News...-and-a4-avant/

[TF110]

Probably near 150kg?

[hcl123]

Hard to tell, it doesn't say if its all aluminium or what parts if not all(the head most likely is aluminium)... but i tend to believe the WEC version though 4L can be even quite lighter than those 190kg ( different species really).

What amazes (again) is the torque, 600Nm (powerful > 5L V8 petrol territory)... for that *only* 272 hp, that is achieved at the 3228 RPM only... which makes to believe the engine is terribly under stated or terribly *cut* in its potential, IIRC VW older 4IH diesels, red line begins at 4K RPM, this is a V6 it could be beyond that... at 4200rpm if pushed that way power would be 353 hp...

This engine could be a dream for after-market tuners... if only they start making transmissions that don't fight against the engine.

[ the WEC version probable torque is above the 1000Nm... again ]

[Pole2Win]

My biggest gripe with diesels is that they simply aren't competitive without turbos. IIRC the regs don't state a maximum displacement for NA diesel engines. Why? Because they aren't powerful enough at high rpm, and possibly because they'd be too heavy as well.