Audi LMP1 Discussion

[Lola T70]

Originally Posted by vyselegend

Once again, if Aston can have their new car race ready for Sebring, Audi has no excuse IMO.

I think the critical word here is if. I do not think Aston Martin will make it and if by surprise they do will be unprepared for a Sebring 12 Hours.

[gwyllion]

More comments on the R18, this time by Treluyer: http://www.endurance-info.com/versio...ance-6313.html Same story: easy to drive, faster in the corner but slower on the straights, worse visibility so traffic will be a bit more complicated.

[chernaudi]

Originally Posted by gwyllion

More comments on the R18, this time by Treluyer: http://www.endurance-info.com/versio...ance-6313.html Same story: easy to drive, faster in the corner but slower on the straights, worse visibility so traffic will be a bit more complicated.

Oddly when I translated the article, Ben seems to prefer the closed car from a safety and comfort standpoint. Could he be toeing the Audi AG company line (after all, he is technically an employee of their organization), or does it harken back to his GT/Super GT/Pescarolo 908 experiences? He also seems to infer that the R18 isn't much different from the old 908, and is in someways better than the GT cars that he's driven, so it's not much more difficult than what he's accustomed to.

He does say that the car is plenty fast over a lap, but like Peugeot, lacks straightline speed due to the 150 horsepower cut, but is much easier to drive than the R15 often was last year.

A more accurate inference is that Audi plans to bring 3 cars and if possible all drivers to the Le Mans test.

[Lola T70]

Originally Posted by chernaudi

A more accurate inference is that Audi plans to bring 3 cars and if possible all drivers to the Le Mans test.

Why would they not? Seems pretty standard practice and logical to bring the team that are going to race to the Le Mans test.

[chernaudi]

ACO requires that only one car show up, and the LM test is manditory if a team has a new rules cars. Teams with grandfathered cars or new cars/packages homologated as a pre-2011 car only show up on a voluntary basis. Also teams can volunteer to send more than one car to the test.

I wonder if Peugeot feel that they're up on their test program if we'll see only one car or two, as they have a 3 car team or if Oreca will turn out with their 2010 908.

As well as how many cars AMR will send to the LM test, as it seems that they're cutting close to make Sebring as it stands now.

[Victor_RO]

Originally Posted by chernaudi

I wonder if Peugeot feel that they're up on their test program if we'll see only one car or two, as they have a 3 car team or if Oreca will turn out with their 2010 908.

Utter BS. Bringing three cars to the test day means that they'll have a potential of 24-30 hours of car time instead of 16-20 for two cars (this is for 8-10 hours of running on the test day). And a serious race team that wants to win Le Mans will want as much running as possible and as much data as possible, and the best way to achieve that is to bring all three cars.

If Audi bring all three cars, Peugeot will bring all three cars. And all 6 factory diesels are entered for Spa for the exact same reason.

[Lola T70]

Originally Posted by chernaudi

ACO requires that only one car show up, and the LM test is manditory if a team has a new rules cars. Teams with grandfathered cars or new cars/packages homologated as a pre-2011 car only show up on a voluntary basis. Also teams can volunteer to send more than one car to the test.

I wonder if Peugeot feel that they're up on their test program if we'll see only one car or two, as they have a 3 car team or if Oreca will turn out with their 2010 908.

As well as how many cars AMR will send to the LM test, as it seems that they're cutting close to make Sebring as it stands now.

Every team will take all cars and drivers available to the test. Not a discussion point never mind a speculation point.

[chernaudi]

It depends on what each team wants to do, just as some teams sat out the ALMS Sebring test, and some LMS teams will sit out the Paul Ricard test.

Audi and Peugeot, as well as AMR will have to attend the LM test with at least one car per rules because they're whole new cars. Whether or not Highcroft will, as bodywork and suspension modifications (for wider LMP1 tires) will take place, is a matter of discussion for the Acura/HPD thread, but it does bring up one point--if a car if modified, like the Highcroft car, or the Rebellion Lolas (new engine), would it need to be tested at the LM test?

That's not to say that Peugeot is complacant, anything but after last year at LM, when 10-12 30 hour tests yeilded no results after the engine formula was tinkered with too much.

And that speaks as to why Audi won't run the R18 at Sebring. Audi got away with rushed test programs with the R8 and R10 because of a lack of serious, well sorted factory competition, as did Peugeot early in the 908's life--it was only when the two cars met in '08 did the R10 prove to be slow, especially at Le Mans, and the 908 fragile.

Audi finally bit the bullet enivitable with a rushed test program with the R15 at LM. And Audi have decided that it's probably better, unless like Peugeot that they've been testing their since last summer (which we know that they haven't), to save the R18 until they know that it's sorted, and they will try to make it faster.

And even if Audi were to know that the R18 would be reliable and fast going into Sebring, Audi have stated that logisitics could pose an issue, as they have plenty of spares for the R15, but maybe not so many for the R18.

Speaking of which, does anyone have an idea if the R18's curved windshield has any advantages/disadvantages over the 908's optically flat item?

[Victor_RO]

Originally Posted by chernaudi

It depends on what each team wants to do, just as some teams sat out the ALMS Sebring test, and some LMS teams will sit out the Paul Ricard test.

Private teams that sit out this kind of test session are not the same thing as big-money three-car factory teams. The teams that want to win Le Mans want mileage in testing. And at the Le Mans test day the best way to gather it is to bring all the cars that they have entered in the race. What's so difficult to understand?

[gwyllion]

Originally Posted by chernaudi

It depends on what each team wants to do, just as some teams sat out the ALMS Sebring test, and some LMS teams will sit out the Paul Ricard test.

Teams can test in Sebring and Paul Ricard as often as they like, because they are permanent race tracks. On the other hand there is only one opportunity to test on the Le Mans circuit once before the race week. So it is obvious that Audi and Peugeot will do the test day with all cars and all drivers.

Originally Posted by chernaudi

Speaking of which, does anyone have an idea if the R18's curved windshield has any advantages/disadvantages over the 908's optically flat item?

Intuitively I would say that a curved windshield produces slightly less drag, but suffers from more visual distortion.

[gwyllion]

Originally Posted by Victor_RO

What's so difficult to understand?

It is often difficult to understand how chernaudi comes to certain speculations

[chernaudi]

Here's a question about the R18 I thought of as a result of watching, of all things, the Daytona 500 and it's associated races.

It regards the R18's front diffuser again, but this time, it regards how it's attacted to the car vs the R15's. On the NASCAR COT, the splitter on it was attached to the car mostly by adjustable stays, with the attendant problems if the car went off the track (usually a busted splitter). On current version of the COT, which doesn't have the indent between the splitter and the bumper, the splitter is attached directly to the nose of the car, and has proven to be more durable.

Going to the R18, in photos where it's been seen with the R15, the whole of the R18's chassis seems to be shorter in height to reduce drag. However, that also means that the nose isn't as high up as on the R15, which means that with the front diffuser the same height off the ground, that the R18's nose box is lower to the ground. And that's also clear when one looks at the splitter stays that connect the diffuser to the nosebox--they're shorter and beefier than on the R15.

It's clear that Audi knew that there'd likely be issues with the R15 in that area, and wanted to fix it for the R18, so the took advantage of lowering the front of the car to strengthen the diffuser stays. That, along with the diffuser being more modular (probably to change the profile of certian sections via interchangeable parts) seems to be hoped to avert the issues that the R15 had at PLM last year, or at least minimize the damage should such issues occur again.

Also, wouldn't lowering the nose (and the whole car) be advantageous in one other area: Center of gravity and the roll center? I think that some of the R15's handling problems were the result of the nose being raised so high, and the zero-keel suspension joined in to raise the front end CG and roll center, hence effecting front end mechanical grip at low speeds.

I don't think, due to the aggressive front diffuser, that Audi has abandoned zero-keel entirely, but I don't think that it's as aggressive in concept as on the R15--maybe more subtle as on the Acura ARX-02. Also, the wider tires should help as well, as the diffuser had to be made more aggressive to recover front downforce.

So, does anyone think that the R18 should be a bit more durable in minor offs than the R15 was at times last year, and could the car being lower offer more benefits than just a substancial drag reduction?

[gwyllion]

You are missing the obvious fact that the R18 is targetting another aerodynamic tradeoff. There is not real need for an "aggressive diffuser to recover front downforce" because overall the car will produce less downforce (and hence less drag).

[templer]

According to german magazines the R18 has an improved aero efficiecy by 10 % compared to the R15 plus. There is also mentioned that the front downforce has increased for more grip at the front axle. So I think Audi have changed the aero balance for more front load.

[chernaudi]

Originally Posted by gwyllion

You are missing the obvious fact that the R18 is targetting another aerodynamic tradeoff. There is not real need for an "aggressive diffuser to recover front downforce" because overall the car will produce less downforce (and hence less drag).

Must I need to bring up the fact that the Acura ARX-02 will likely only be marginally more poweriful than the new LMP1 diesels, and defninlty lacking torque? It ran a diffuser just as aggressive as the R18 because of the wider tires, and ground effects isn't as taxing on drag as topside bodywork is.

Granted, the Lola T600 that ran at LM in the early 80's ran F1 ground effects on it, but it was designed for the IMSA GTP championship and had an underpowered Cosworth DFV as it's engine. So it had a gutless engine and too much drag as it was designed for sprint races. Porsche ran similar ground effects on the 956, but they had the power and the bodywork to do it.

And the 2013 F1 cars will likely produce the same amount of downforce as the current cars in spite of topside bodywork restrictions because of ground effect. Also, I have noticed that the new Pug's front diffuser seems to be a bit more aggressive from what little can be discerned from it because of the wider tires.

Either the diffusers are more aggressive (why does on think that the area on the R18's diffuser is more hunched up--downforce recovery as the wheels and tires are about an inch wider than normal and the attendant wheel clearence issues), or Audi and Peugeot are hoping that the wider tires' superior mechanical grip will make up for it, which I don't think is entirely the case, which brings us back to the questions about the R18's front tub being lower (reduced zero-keel/lower front end CG?) to work with the wider tires as well, and the fact that Audi and Peugeot know that with power being capped to 550-580 bhp (who know really what these cars are making, even though both Audi and Peugeot seem to be claiming at least 550), cornering is the best place to make up time.

I think that there's more to be gained from the topside bodywork modifications that Audi and Peugeot have made then by sacrificing ground effect, as ground effect is about as close to a free lunch as one can get with aero on these cars.

And to paraphrase what the poster above me has mentioned, Audi seems to be making more front downforce compared to the R15 and that overall the car is at least 10% more effcient in LM areo trim. And that there has been a shift in areo balance towards the front, probably in respect to the wider front tires.

[gwyllion]

Originally Posted by chernaudi

Must I need to bring up the fact that the Acura ARX-02 will likely only be marginally more poweriful than the new LMP1 diesels, and defninlty lacking torque? It ran a diffuser just as aggressive as the R18 because of the wider tires, and ground effects isn't as taxing on drag as topside bodywork is.

The Acura ARX-02 was designed for high downforce ALMS tracks, and not for low drag Le Mans. Moreover it had a bit more power than 2011 LMP1s.

Originally Posted by chernaudi

who know really what these cars are making, even though both Audi and Peugeot seem to be claiming at least 550

As far as I know, no official power number has been released for the R18. Officially we only know that it is a 3.7 V6 TDI and that is it.

Originally Posted by chernaudi

And to paraphrase what the poster above me has mentioned, Audi seems to be making more front downforce compared to the R15 and that overall the car is at least 10% more effcient in LM areo trim. And that there has been a shift in areo balance towards the front, probably in respect to the wider front tires.

in his analysis of the aero numbers on the windtunnel picture (see here) Mike also noticed a front biased aero balance (53% on front).

However, a improved aero efficiency only signifies a better lift/drag ratio. That only means that the drag has been reduced while the reduction in downforce has been relatively less. The fact that the aero balance has been shifted forward, does not nessarily mean that it will have more downforce in absolute numbers.

BTW

[Lola T70]

Originally Posted by chernaudi

Must I need to bring up the fact that the Acura ARX-02 will likely only be marginally more poweriful than the new LMP1 diesels, and defninlty lacking torque? It ran a diffuser just as aggressive as the R18 because of the wider tires, and ground effects isn't as taxing on drag as topside bodywork is.

Granted, the Lola T600 that ran at LM in the early 80's ran F1 ground effects on it, but it was designed for the IMSA GTP championship and had an underpowered Cosworth DFV as it's engine. So it had a gutless engine and too much drag as it was designed for sprint races. Porsche ran similar ground effects on the 956, but they had the power and the bodywork to do it.

And the 2013 F1 cars will likely produce the same amount of downforce as the current cars in spite of topside bodywork restrictions because of ground effect. Also, I have noticed that the new Pug's front diffuser seems to be a bit more aggressive from what little can be discerned from it because of the wider tires.

Either the diffusers are more aggressive (why does on think that the area on the R18's diffuser is more hunched up--downforce recovery as the wheels and tires are about an inch wider than normal and the attendant wheel clearence issues), or Audi and Peugeot are hoping that the wider tires' superior mechanical grip will make up for it, which I don't think is entirely the case, which brings us back to the questions about the R18's front tub being lower (reduced zero-keel/lower front end CG?) to work with the wider tires as well, and the fact that Audi and Peugeot know that with power being capped to 550-580 bhp (who know really what these cars are making, even though both Audi and Peugeot seem to be claiming at least 550), cornering is the best place to make up time.

I think that there's more to be gained from the topside bodywork modifications that Audi and Peugeot have made then by sacrificing ground effect, as ground effect is about as close to a free lunch as one can get with aero on these cars.

And to paraphrase what the poster above me has mentioned, Audi seems to be making more front downforce compared to the R15 and that overall the car is at least 10% more effcient in LM areo trim. And that there has been a shift in areo balance towards the front, probably in respect to the wider front tires.

Please define "aggressive" when you talking about front diffusers, is it just the look, or are you including design profile, cord length, it's potential pitch sensitivity, what is it exactly.

You have mentioned it many times when you thought the R15++ at Sebring would have R18 diffuser and also now with Peugeot and Audi. Just curious.

[chernaudi]

Who knows, but we have to remember that the R18's a coupe, and coupes can run more downforce for drag numbers comparable to an open car. I don't think that in HD trim that downforce will be pared off that much considering that variable.

Just as Mike said about the early R15, the usual design paragram is to design for the lowest drag practical, then add downforce as needed. And the R18 seems to be designed for ultra low drag--it's very short in height overall, and, especially in the valley between the sidepods and the tub, is extremely low, and makes the 908 look conservative.

Audi seems to be looking at as little drag as possible for LM, with room to pile on downforce for the sprint races with a minimal drag penalty.

That also goes along with one of Mike's thories about the R18, and how the nose of the car is designed for the fenders to funnel air around the sides of the fenders rather than just over them. Not only does that improve airflow over the front diffuser (to recover downforce lost by it's narrower span, and probably helps feed "clean" air to the front brakes (while minimizing the size of the brake ducting, reducing drag and improving efficiency of both the ducting and the diffuser flow), but probably can allow Audi to run dive planes like the R8/R10/R15 had to produce Acura-like downforce numbers in sprint trim, but without the drag penalty.

Of course, the Acura ran those huge dive planes in part to keep tire temp. up in high speed corners. Of course, those huge dive planes mean drag. If similar downforce levels can be had for smaller dive planes or more downforce for similar drag, that's a net gain.

If the R18 in sprint race trim runs dive planes like the R15 or something of that nature, using Mike's theory/observation of the R18, Audi will have a very potent package for the sprint races without sacrificing LM performance. Of course, that depends on what Peugeot has and how they'll respond if they find that they're at a disadvantage.

And that also goes to one more thing that struck me about the R18 (and the R15 last year as well), which is that those cars lack the louvers that the R10 and certainly the early R15 had in the sidepods. I think that Audi may have a fairly nifty cooling system on the R18 that was tested on the R15 last year, though it probably also has a lot in common with the R8/R10 system. Either the cooling system is pretty effient in it's own right, of Audi has figured out a good system of directing air into the sidepods with out excess drag or the need for those louvers that the 908 still has. That's good for aero as well.

[chernaudi]

Originally Posted by Lola T70

Please define "aggressive" when you talking about front diffusers, is it just the look, or are you including design profile, cord length, it's potential pitch sensitivity, what is it exactly.

You have mentioned it many times when you thought the R15++ at Sebring would have R18 diffuser and also now with Peugeot and Audi. Just curious.

Look at a head on shot of the R15 and of the R18. The R18's diffuser had a more pronounced "arch" between the wheelwell and the stays/nosebox area.

And as I said, it was probably done to make up for wheel/tire width and clearence issues and to generate downforce similar to a conventional diffuser.

Of course, the Audi R8 in it's early days switched to a narrower rear diffuser because of tire width, and it actually produced more downforce than the wider one.

[Lola T70]

Originally Posted by chernaudi

Look at a head on shot of the R15 and of the R18. The R18's diffuser had a more pronounced "arch" between the wheelwell and the stays/nosebox area.

And as I said, it was probably done to make up for wheel/tire width and clearence issues and to generate downforce similar to a conventional diffuser.

Of course, the Audi R8 in it's early days switched to a narrower rear diffuser because of tire width, and it actually produced more downforce than the wider one.

So only your visual take on it then.

[gwyllion]

Marco Bonanomi is Audi's new reserve driver for Le Mans. He will also do some test and development work.

Audi has also changed their DTM lineup extensively. Alexandre Premat, Markus Winkelhock and Katherine Legge are out and replaced by rookies Edoardo Mortara, Filipe Albuquerque and Rahel Frey. Rockenfeller is promoted to team Abt where he replaces Tomczyk.

source: http://www.audi.com/com/brand/en/exp...omers_for.html

[Simmi]

Originally Posted by gwyllion

Marco Bonanomi is Audi's new reserve driver for Le Mans. He will also do some test and development work.

Erm. Interesting choice. Has he ever had any experience of anything outside of open wheel competition? His wikipedia page only goes as far as 2009.

http://en.wikipedia.org/wiki/Marco_Bonanomi


EDIT: Ok yeah he drove for Audi in Italian GT last season.
http://www.autosport.com/news/report.php/id/89612

[Lola T70]

Originally Posted by Simmi

Erm. Interesting choice. Has he ever had any experience of anything outside of open wheel competition? His wikipedia page only goes as far as 2009.

http://en.wikipedia.org/wiki/Marco_Bonanomi

Did many of the Peugeot drivers or in fact most of the original Audi drivers for that matter?

he drove with Audi Sport Italia last year in the R8.

[Simmi]

Originally Posted by Lola T70

Did many of the Peugeot drivers or in fact most of the original Audi drivers for that matter?

he drove with Audi Sport Italia last year in the R8.

Yeah it's amazing how many of the very best endurance drivers had to take a sideways step after their single-seater careers hit a road block.

[Lola T70]

Originally Posted by Simmi

Yeah it's amazing how many of the very best endurance drivers had to take a sideways step after their single-seater careers hit a road block.

Bonanomi was teammate with Filipe Albequerque in Italy last year alongside Dindo Capello so maybe some inside knowledge from Capello lead to those guys being picked up.