Audi LMP1 Discussion

[gwyllion]

[chernaudi]

Rhetorical question: If so, why didn't Peugeot run the new bodywork at Sebring? After all, Sebring is a high downforce track, and I certianly don't think that the nose would be used outside of Le Mans. And if the tests at Paul Ricard were with the LM bodywork, it certianly could've been used, at least if logicistics issues didn't cause problems.

We also have to remember how much Highcroft stuggled in the ALMS last year when they ran their LM aero package in the hopes that it'd help them in traffic with higher straightline speeds. Didn't really pan out, as it at times made the car undriveable, meaning that compormises made for LM don't neccesarily work elsewhere (though Strakka ran a similar setup everywhere and didn't have such issues).

If such things would make for an improvment across the board, why waste 6 months with their Sebring spec cars? After all, the R15 taught us that it's easier to add downforce to a slippery car than to take downforce/drag off a car built for downforce circuits. Of course, much of this is rhetorical and academic, but whey not fight and wring out every advantage you can find when you know how to make them?

And if the R18 is faster in deed than the sprint spec 908 (a possibility, though by now much isn't entirely clear, as Peugeot may've been sandbagging a tad), it's probably not by a huge gap in one area. It's probably by little gains in multiple areas. Peugeot's big advantage over anything that Audi has had in recent years has been straightline speed, partly down to power, and partly due to the closed car. Now that Audi has a closed car and new regs that favor smaller capacity/less powerful engines are in effect, it'll be interesting to see how much Audi has closed the gap or gained the inititive and how they've done it.

However, if we go back to the R15 (which it's claimed that the R18 was about 1.5 second faster than on a flying lap), it's partly down to the tires, improved aero, and having an engine built to the new regs. Little differences in multiple areas that can add up to a lot. However, as we've seen in F1, which is now a sport that's decided by fractions of a second, a lot of work has to be done to make even a little gain.

[JAG]

I would have thought the 908 LM is the basis for their sprint car post Le Mans.

[chernaudi]

Or a hybrid specification? I can't see them using all of it due to the fact that aero considerations for LM and about everywhere else is different. But some of the stuff on the LM package should, at least in theory, be usable.

Which of course leads to wonder if Audi will make additonal changes to the R18 for Le Mans?

[gwyllion]

Originally Posted by chernaudi

Peugeot's big advantage over anything that Audi has had in recent years has been straightline speed, partly down to power, and partly due to the closed car. Now that Audi has a closed car and new regs that favor smaller capacity/less powerful engines are in effect, it'll be interesting to see how much Audi has closed the gap or gained the inititive and how they've done it.

I doubt that Audi has closed the gap in the engine department.

The reasons that Baretzky gave regarding the choice for a V6, did not include better performance nor better efficiency than the more conventional V8 configuation. The V6 was chosen for chassis reasons (light, short, compact, short, low cfg, ...).

Originally Posted by chernaudi

Or a hybrid specification? I can't see them using all of it due to the fact that aero considerations for LM and about everywhere else is different. But some of the stuff on the LM package should, at least in theory, be usable.

Above I already have a list of elements that can easily be carried over.

BTW you still have not provide a source why ASR is more difficult with diesel engines.

[MihokS5]

Gwyllion, you don't think that there is a chance Audi's engine will be just as powerful as Peugeots? I know it seems impossible with a V6 and a single turbo but you never know I guess...

[chernaudi]

Baretzky said that the R18's engine is making more power than the R15's performance ballanced engine, and we know that Peugeot commented at Sebring (on the race highlights broadcast) that the R15 was making plenty of power down the straights, enough that the Pug's best hope for a pass attempt was to get on the R15's tail and try for a slingshot/drafting pass.

Either Peugeot was sandbagging in their engine department (reliability or posturing?), or with the current regs, they've lost a bit of their edge, or Audi may have the better aero and/or chassis (on the R18).

However, the biggest thing that Peugeot said about the Audi R15's straightline speeds at Sebring wasn't so much top end (where the cars seemed to be equal), but under accelleration. And that's down, at least from what I've seen, to the R15 having a slight torque advantage, or the R15's VTG turbos, and obviously, Audi have invested in 1-2 VTGs for the R18's V6.

That makes me wonder if it's down to the turbos, and if it is I'd have to say that I'd be shocked that Peugeot hasn't adopted VTGs if they haven't (the fairly small size of the Pug's turbos has been referenced), since the principal is now proven and that Audi and Peugeot share Garrett/Honeywell as turbocharger suppliers.

And for the ASR, that's the only legal form of TC legal under ACO/IMSA rules. And ASR is governed by sensors that track the wheel or axle, which cut power. Which is fine on gasoline engines, as they have spark plugs--pretty simple.

Things aren't as easy on diesel engines, as the only way to cut power is, as you've suggested, cutting the injectors. However, I don't know if it's any more effective than killing spark plugs/coils. Part of the reason why Audi didn't run ASR on the R10 in most of '06 was because of reliability reasons and that it took them forever to get it to work in the first place, and Audi has made ASR systems for gasoline engines for years, though it was often teamed with ESP (which is currently illegal under the present regs).

[gwyllion]

Originally Posted by MihokS5

Gwyllion, you don't think that there is a chance Audi's engine will be just as powerful as Peugeots? I know it seems impossible with a V6 and a single turbo but you never know I guess...

Other persons on this forum like knighy are in a better position to answer this question.

I can only give a comment from Baretzky in 2005:

So why did you choose 12 cylinders? (perhaps the first question should have been – Why did you choose to build a diesel? – but we’ll get to that answer in due course)

“We carried out a feasibility study with 10 and 12 cylinder engines. Because the combustion pressures are so high, it is better to distribute those pressures across 12 cylinders rather than eight or ten.”

Ulrich Baretzky mentioned a figure for the pressures within a production diesel of 160 bar, “but we are far beyond that with the R10.”

source: http://archive.dailysportscar.com/su...rs/audir10.htm

I don't see why this rule would no longer hold.

As I mentioned in the 908 topic, the V12 TDI produced around 60 bhp per cilinder. Audi's V6 TDI has to make more than 90 bhp per cilinder, whereas Peugeot's V8 HDI only around 70 bhp per cilinder. This signifies that the Peugeot engine will have more manageable combustion pressures and temperatures.

[gwyllion]

Originally Posted by chernaudi

Things aren't as easy on diesel engines, as the only way to cut power is, as you've suggested, cutting the injectors. However, I don't know if it's any more effective than killing spark plugs/coils.

No diesel is injected and hence no combustion can take place.

With a petrol engine, no spark is given and hence the fuel that has been injected, will not burn in the combustion chamber.

Both techniques have the same effect: engine combustion and hence power delivery to the wheels is interrupted.

Originally Posted by chernaudi

Part of the reason why Audi didn't run ASR on the R10 in most of '06 was because of reliability reasons and that it took them forever to get it to work in the first place.

So Audi toke things safe in the first year, where it did not have any real competition. That does not mean that much. Peugeot has had ASR since the beginning.

BTW in your earlier post you speculated that:

Originally Posted by chernaudi

The big rumor about the McLaren MP4-23's wheel and it's extra paddles is that they were used to increase/decrease the amount of torque/power available at the rear wheels.

According to http://www.f1technical.net/developme...fe7bb435bd8409 the system you mention, functions as follows:

The new system enables the driver to change gears and simultaneously change to a different engine mapping by pulling the paddles at the same time. Most importantly, it looks to be allowed by current regulations as these only stipulate that engine mappings can only be changed by the driver. Any automatic change acting upon a gear shift is forbidden.

The LMP rules explicitely allow traction control system operating on the engine (article 1.10.4). It is known that Audi and Peugeot limit the torque of the engine in the lower gears. Therefore there is no need for this manual engine mapping change paddle.

[chernaudi]

It was speculated that McLaren were using such a system in '08 in part because of TC being banned in F1, and that selecting engine maps would dictate the power and torque flow to the rear wheels.

Of course, with ASR being legal, Audi and Peugeot tending to have engine maps that restrict power in the lowest couple of gears (though we don't know if that's of much use now with the reduced power--if the old gearboxes can handle 700+hp and 900 ft/lbs of torque, they should easily handle the 550+hp and 600+ft/lbs of torque that the R18 and the 908 now make--Corvette's gearboxes in the GT1 cars had to deal with 650hp and 600+ft/lbs, and did so easily) should make such a system redundant on their new cars.

But if it's not for something like that, it seems that a hand clutch is an obvious choice unless forbidden by the regulations. And if that's the case, what else are they for? Redundancy for the normal paddles?

[gwyllion]

Originally Posted by chernaudi

But if it's not for something like that, it seems that a hand clutch is an obvious choice unless forbidden by the regulations.

Why do you never check the rules yourself?

9.5 - Clutch :
Only one clutch is authorised for the combustion engine.
The only energy which can operate the clutch is the one provided by the driver. This one must exert with its foot all the pressure necessary to operate and control the mechanism of the clutch.

That rules out that a hand clutch theory. I should have read the rules before making this suggestion

[Fogelhund]

Originally Posted by gwyllion

Why do you never check the rules yourself?

Takes too much time away from simply making things up.

[chernaudi]

Obviously they have to be for something, considering that Peugeot likely have a similar set up. KERS and clutch are ruled out. As I've said, it could be a back up system for the gear shift, but how often are gear shift failures related to electronics in the engine bay electronics and they're in sort of an awakward position for gear change paddles.

I guess that we'll have to wait for an explanation from Audi or Peugeot on this, unless anyone else can make a guess on what they could be for. Of course, there's the McLaren MP4-23 system, which we know is to select engine maps to govern torque and power at the rear wheels. But with TC that does seem to have some semblance of functionality (especially with the decreased power outputs), why use it for that?

Problem is, like the R18's engine and transaxle layout, we'll probably have to wait until at least the LM test day, which is almost a month away from now.

[gwyllion]

Originally Posted by chernaudi

As I've said, it could be a back up system for the gear shift, but how often are gear shift failures related to electronics in the engine bay electronics and they're in sort of an awakward position for gear change paddles.

Which of the paddles do you think, are positioned awkwardly?

The paddle shifters of the R15 were positioned in the middle of the steering wheel (see here), but on the 908 they much higher (see here). In F1 cars the top levers are for gearshifts and the bottom ones for the clutch (e.g., see here).

I have another theory about the function of the extra paddles. They were added to annoy you

[JAG]

Originally Posted by chernaudi

Or a hybrid specification? I can't see them using all of it due to the fact that aero considerations for LM and about everywhere else is different. But some of the stuff on the LM package should, at least in theory, be usable.

Which of course leads to wonder if Audi will make additonal changes to the R18 for Le Mans?

It could just be Peugeot always planned to phase in new aero at a later date whereas Audi had no choice given the switch to a coupe.

[chernaudi]

Originally Posted by gwyllion

Which of the paddles do you think, are positioned awkwardly?

The paddle shifters of the R15 were positioned in the middle of the steering wheel (see here), but on the 908 they much higher (see here). In F1 cars the top levers are for gearshifts and the bottom ones for the clutch (e.g., see here).

I have another theory about the function of the extra paddles. They were added to annoy you

The Audi deal seems (in the past) to use the two middle fingers to opperate the paddles (immediately behind the wheel spokes). I don't know what Peugeot is up to, though their wheel seems to be similar in concept overall, though it seems that the Audis' wheel has a telem. screen on it, while on the 908, it seems to be mounted on the dashboard to the left of the driver.

I'm starting to wonder if controling the TC could be a function, as, even though it might be a bit awakward (reaching up with the index finger to flip a paddle), it's got to be better than trying to find it on the dash, as the R18 is RHD, remember, and they can't really put a lot of the controls within reach of the driver's right hand with that style of cockpit. It doesn't help that 90% of all people (and hence about 90% of race car drivers) are right handed.

If it is to control the TC, it might not be the first thing to think of as far as the TC's control and off/on function, but Audi may've not have had much of a choice with the R18 being RHD and those paddles might be the best compormise that Audi Sport could find.

Of course, TC control could be one of the numerous dials on the wheel itself, and the extra paddles could be useless or have a yet to be disclosed use that we haven't thought of.

And there's one more piece on the car that bears similarities to a recent McLaren F1 design--the R18's roof snorkel bears similarities to the McLaren MP4-26's engine intake in that there's a carbon fiber collar around the intake Could that collar be used to try and accellerate air flow into the engine/cockpit intakes or does it serve another purpose.

[CTD]

The paddles could be for:
Lighting and or Pit speed control, maybe even engine start.

[cmk]

Anyone ever do paddle-operated brake balance adjustment? That is the sort of control you could make use of multiple times every lap.

[gwyllion]

A much longer HD video of the R18: http://www.quattroworld.com/r18/audi...gh-definition/

The V6 TDI engine seems to produce quite some smoke under heavy acceleration

[Félix]

Now, if the diesels have an advantage (yeah, that can happen!), why not enforce the "no smoke" regulation a tad more strictly?

[gwyllion]

Originally Posted by gwyllion

A much longer HD video of the R18: http://www.quattroworld.com/r18/audi...gh-definition/

An interview with Ullrich, H and Baretzky has shown up at

Vlad1977 already posted this link in the 908 topic, but it belongs better over here.

H joked that "if Darth Vader had a car, this (the R18) would be his."

[gwyllion]

Originally Posted by vlad1977

Baretzky says that 'if you make an engine like the V6, you don't do it just for one year'.
So Audi might have chosen the V6 in regard of a future plan to add an electric engine to it, even if it means that for the first year, it has less power than a V8. Perhaps the V6 is better suited to form the base of a hybrid engine (less mass, better center of gravity).

As you can read in an earlier message of me in this topic, Baretzky gave two reasons for the V6 choice: more room for the future addition of KERS and experience with high combustion pressures, which is relevant for road engines.

[gucom]

just a silly idea, but do you guys think we could petition Audi to keep it in black / carbon? it would really be a massive shame to see it lose some of the badness it has now!

[chernaudi]

Originally Posted by gwyllion

A much longer HD video of the R18: http://www.quattroworld.com/r18/audi...gh-definition/

The V6 TDI engine seems to produce quite some smoke under heavy acceleration

Probably no worse than the Pug would if they were at full song and certinaly no worse than the R15s did at Sebring--they smoked a lot at low speed, namely during the pace laps and from either a dead stop or going from minimal load to full load in a short period.

Of course, that sooty exhaust smoke was proof positive of how much power the old 908s were making at full rich.

And it's interesting that Baretzky doesn't have a hugely high opinion on KERS, but Audi Sport themselves have said in attitude, if not words, that the R18 was designed for KERS at some stage, possibly late this year depending on when/how they test it. You don't have that short engine and a fairly long wheelbase without having plans to put something back there soon (wheelbase is more to control weight distribution than anything else on the current cars).

And Pruett in his early write up about the R18 said that Baretzky wasn't a fan of the V6 layout either, but was convinced to have faith in it, and has also brought about the discussion of the turbo/turbos in the V induction arrangement. Of course, Marshall also said that the R15 would run wider wheels and tires at Sebring, which that appears to have not happened.

Also in the video, the R18s seemed at times to be louder than in the other videos posted here, but then again, you can clearly hear the cars bouncing off the curbs and engine noises from presumably the HPD ARX-01 in the distance even when the R18 was close by.

And it does seem to be cornering quite a bit faster than we've seen the R15 or the old 908 do at times as well, even with less downforce.

Of course, I'm still waiting for the Fourtitude write up and additional videos that they've gotten. But since they've only posted a link to their long awaited '10 LM24 review (though it's not up on their site yet, nor have they updated their incomplete race gallery), it may be a while before they get all their R18 stuff up.

[chernaudi]

Similar to one of the previous videos, but includes about a minute and a half of slow motion footage:

http://www.youtube.com/watch?v=0rXf0F3S_1M

Shows how really god-awfully bumpy Sebring is, and shows a new light in full screen HD on the smoke. It doesn't seem to be doing it a lot compared to the R15 or the old 908, but it does seem to eject a puff of smoke out the exhaust immediately after up shifts and going from partial to full throttle in a sudden burst--could there be some diesel fuel or vapor getting to the exhaust system on overrun, which in theory shouldn't really happen?