Audi LMP1 Discussion

[leglizone]

Audi is in Monza in these days with 2 R18. Apparently there are no aerodynamic news on them.

[gwyllion]

Thanks. According to http://www.motorsportuniverse.com/AudiR18.html the two Italians (Capello, Bonanomi) and Rockenfeller were driving.

More pictures on https://picasaweb.google.com/1030266...283/AudiR18TDI

[gwyllion]

Originally Posted by gwyllion

Thanks. According to http://www.motorsportuniverse.com/AudiR18.html the two Italians (Capello, Bonanomi) and Rockenfeller were driving.

The article has been updated and now includes an English translation. Dumas and Fassler were also driving. One car was doing an endurance program and the other setup work.

[MulsanneMike]

We now have images in hand of the Audi R18. The bounty worked! If you weren't aware, we also have received images of the 908. Give Sam and I a couple of days/weeks to sort out how to stagger them out (I have to deal with their "slow" print cycle ;0)) . In the mean time, the Audi's rear end is as expected: torsion bars, almost vertical dampers (angled to meet bellcrank which is angled for torsion bars), 3rd spring. The most interesting thing is the carbon bellhousing structure. It's much more intricate than the 908s in that it extends full length and the gearbox cradles inside the open ended structure. All rear suspension pick ups mount to the carbon. The trailing arm pickups are supported by metallic structures behind them that "stitches" the open ended carbon structure, tying everything together.

[chernaudi]

The gearbox casing/bellhousing/suspension arrangment seems to point to at least one of two things:

1--Audi are going for light weight to move ballast to the front of the car to get the front tires to work, or

2--Audi have adopted a "quick change" gearbox casing that can be removed from the car without the need to take the suspension with it to allow for quick changing of transmission internals/differential for maintanance/repair, or to tune gear ratios.

Any possibility of that scinerio? Pruett from Speed reported on this shortly after the R18 was launched, but, at least until Mike and Sam get their photos up and sorted, we might not have any big time answers unless someone catches Audi in the act of working on the gearbox.

Also, for the Monza test, it was reported that the R18's ran 1:28s without the chicane on the front straight.

And one thing that really strikes me about the R18 is that compared to the R10 and R15 especially, that the R18 at Paul Ricard and Monza seems to be using a lot more curbing than those cars ever did.

Whatever Audi is doing there, it seems to work at least on a clean track, but maybe not one that's dirty?

[MulsanneMike]

Originally Posted by chernaudi

The gearbox casing/bellhousing/suspension arrangment seems to point to at least one of two things:

1--Audi are going for light weight to move ballast to the front of the car to get the front tires to work, or

2--Audi have adopted a "quick change" gearbox casing that can be removed from the car without the need to take the suspension with it to allow for quick changing of transmission internals/differential for maintanance/repair, or to tune gear ratios.

Any possibility of that scinerio? Pruett from Speed reported on this shortly after the R18 was launched, but, at least until Mike and Sam get their photos up and sorted, we might not have any big time answers unless someone catches Audi in the act of working on the gearbox.

Also, for the Monza test, it was reported that the R18's ran 1:28s without the chicane on the front straight.

And one thing that really strikes me about the R18 is that compared to the R10 and R15 especially, that the R18 at Paul Ricard and Monza seems to be using a lot more curbing than those cars ever did.

Whatever Audi is doing there, it seems to work at least on a clean track, but maybe not one that's dirty?

Based on exchanges I've had, this is all about reducing weight (polar moment and cg, etc., etc). Obviously the regs don't allow quick change gearboxes for the race, and there isn't a need to do so for practice, at least not as a PRIMARY design goal.

[chernaudi]

Audi did claim that by 2007, both Joest and Champion got changing the internals on the R10's gearbox down to just over 5-6 minutes with the old cassette system the used, and that was carried over to the R15.

Pruett said that Audi may've deviated somewhat from that, in that the basic principal is still there, but it can be done faster with the casing removed from the car. Either way, Audi are aiming perhaps for ease of maintaince and trying for sub 6-7 minute gearbox internal changes with the gearbox assembly, and it seems that the bellhousing carrying much of the suspensions loads my be an attempt to get a "quick change" (ie, easily removable) gearbox casing to allow for quick repairs and tuning.

Granted, as you said, in a practice session this isn't very useful, but time saved there can mean more track time, even if it's only a couple of more minutes, and can mean the difference between finishing positions during a race.

Either way, this does seem to be an interesting concept, and it's been said that the R8's/R10's modular design inspired a lot of similar concepts on the R18, as the R15 was a relative nightmare to work on--not what you'd want for an endurance racing car, or for a car that might end up eventually in private hands for the ALMS/LMS (though if that happens is up in the air--Audi Sport wants semi-works private teams in the ALMS. LMS, and maybe the ILMC in the future, but that depends on the regional importers/represenatives).

And as I've mentioned, the R18 also seems to be a fairly compliant/softly sprung car, as I've seen it in videos hit curbs and it not really be phased by it, unlike the R10 and R15. With the R18 using a suspension system front and rear that seems to be a refinement of the R15's is the R18 able to use the suspension better (weight distribution, better chassis, etc), or is that due to trying to make the car corner faster to make for reduced straightline speeds?

[CTD]

Personally i don't think Audi are that interested in being able to change gearboxes or cassettes.
It's pretty long ago that Audi has had a gearbox failure, as i remember it (the last one i can remember was in the R8)

[Victor_RO]

Last gearbox-related failure on an Audi was Silverstone last year, although that was an input shaft actually.


EDIT: Last proper proper gearbox failure on an Audi was Le Mans last year on the 15 Kolles car. At least the result sheet lists the reason for the retirement as "gearbox".

[chernaudi]

Not an input shaft, but a $5 dollar part in the differential.

If Allan was able to get it a couple hundred more feet down the track, he could've made pit in and we could see if there was any validity to those claims.

However, if the R10 and R15's gearboxes could handle nearly 900ft/lbs of torque being driven though them, then in theory, 600+ft/lbs shouldn't be an issue, but as the R15 showed us, the freak failure can happen, and the R18 has a six speed, vs a five speed for the R10 and R15. But what bodes well for Audi there is that the Corvette C6R GT1 made similar power and torque, and gearbox failures were very rare on those cars.

[Victor_RO]

Originally Posted by chernaudi

But what bodes well for Audi there is that the Corvette C6r GT1 made similar power and torque, and gearbox failures were very rare on those cars.

Didn't stop it from happening though. Le Mans '09 on the 64 car and on one or two more occasions during '08 and '09 in the ALMS. If it's going to happen, it's going to happen no matter how much it's engineered against. See the early R8's gearboxes.

[gwyllion]

They changed the gear cluster on the winning (!) R10 during the 2006 Le Mans 24 hours.

The winning car made only 27 pit stops during the 24:04:47.325 hours. The car only made two unscheduled pit stops: once to change the gear-cluster in the gearbox (03:47 a.m.), and once due to a slow puncture (04:23 a.m.).

Thanks to Audi Sport’s revolutionary new gearbox concept the gear-cluster change required a mere 9:50 minutes – including refuelling and change of tyres.

Their quick change solution helped secure the victory that year.

Of course that was before the arrival of Peugeot. Now only the car with the "perfect" race stands a chance at victory.

[chernaudi]

Originally Posted by Victor_RO

Didn't stop it from happening though. Le Mans '09 on the 64 car and on one or two more occasions during '08 and '09 in the ALMS. If it's going to happen, it's going to happen no matter how much it's engineered against. See the early R8's gearboxes.

The issues that Audi had at LM in 2000 weren't gearbox related--they were having suspension joint failures, incluiding one that put McNish off the road at the test day. The #9 Audi damaged it's rear suspension on a curb, and the #7 had a tire blowout. The #8 didn't have any rear suspension issues and thus didn't near a rear end change.

In '01, the R8s probably had the same issues that the Bentleys did--either water in the electronics, or issues with the tire pressure sensors messing with the gearchange system. Both of which could've disabled the electronic elements of that system--one R10 at Mosport in '07 had literally a $5 electronic part take out the gear change system on that car.

Mechanically, these cars seem to be fairly sound, especially compared to about 10 years ago, but the electronics, that still seems to be the source of most issue of any type on these cars.

Of course, Audi fighting to get the weight of the R18 to be as light as possible motivated a lot of the design elements, but the fact that the suspension isn't directly connected to the gearbox does open up it seems the ability to work on the gearbox itself easier, even if it's only of acdedmic use in practice to change gear ratios--besides, one Ganassi DP at Daytona this year changed out a gear cluster for that reason, and I don't think it even lost a lap, though the change was done under yellow.

[gwyllion]

Originally Posted by chernaudi

Mechanically, these cars seem to be fairly sound, especially compared to about 10 years ago, but the electronics, that still seems to be the source of most issue of any type on these cars.

Don't forget that the R18 is the first Audi LMP with an electrical gear shift mechanism.

Originally Posted by chernaudi

Even if it's only of acdedmic use in practice to change gear ratios--besides, one Ganassi DP at Daytona this year changed out a gear cluster for that reason, and I don't think it even lost a lap, though the change was done under yellow.

A change in gear ratio during the race With all the preparation (testing, simulation, ...) that goes into Le Mans, the optimal gear ratios will be determined a long time before the start of the race.

[Dead-Eye]

Originally Posted by gwyllion

A change in gear ratio during the race

It did happen at Daytona, but it was pretty mindboggling that they hadto and I wouldn't expect Audi to make a similar error.

[gwyllion]

Originally Posted by chernaudi

Pruett said that Audi may've deviated somewhat from that, in that the basic principal is still there, but it can be done faster with the casing removed from the car.

The Inside The Audi R18 article of Marshall Pruett contained more inaccuracies. Some examples:

The R15, drawing heavily on aero concepts employed by Ferrari, proved to be a mystery to the engineers at Audi.

Only the vented nose was inspired by the Ferrari F2008 car.

With the R18, Gershbacher started with a clean sheet of paper, avoiding the F1-inspired aerodynamics his predecessor fell in love with.

The whole "air through car" concept originated from their DTM car.

The R18 also sports air conditioning—another first—due to the regulations requiring AC in closed-cockpit cars.

The latest information is that AC will not be needed.

The choice of aluminum was made again due to the team being unable to maintain the surface quality they desired. After being subjected to impacts from rocks and debris, the resulting pits from wear to the top and bottom of the splitter generated a surprising loss of downforce.

In http://www.mulsannescorner.com/newsnov10.html Mike gives very different explanation for the aluminum front splitter, namely manufacturing cost.

It is believed the meshed opening in the nose of the R18, amongst other things, feeds cold air to the turbo.

That opening is used to cool the cockpit.

He has also apparently chosen to cool the intercoolers through the duct atop the cockpit.

The intercooler are located in the side pods. The roof duct feeds the engine.

The third iteration of the R15, the R15 ‘plus plus,’ will race at the 12 hours of Sebring next March. The plus plus utilizes the same wide tire arrangement as the R18, and is believed to serve as an R&D car to help Audi and Michelin gain further data on the new front tires.

The R15++ turned out be the R15+- (identical to R15+ except with less power).

Disclaimer: This is not meant as a criticism. A lot of details (e.g., engine configuration) were spot on.

[chernaudi]

Fine, I'll wait until Mike and Sam's photos get posted. But why have the rear suspension attach to extensions from the bellhousing instead of the gearbox casing, which at least is in theory a simpler arrangment?

Either Audi have something going on with the gearbox as far a an easily removed module, or they know something about the bellhousing extensions and suspension mounts proving some other advantage.

[gwyllion]

Originally Posted by chernaudi

Audi have been testing at Monza very recently, as in the past few days:

http://www.youtube.com/watch?v=QHHAlYCTIiQ

Another video of the Monza test taken on Tuesday (17/05): http://www.youtube.com/watch?v=peSzjwFtmu4
Don't forget to turn up the volume because the R18 is extremely quiet.

[cdsvg]

From http://www.youtube.com/watch?v=peSzjwFtmu4 it looks like the #2 car has been running with subtly different front and rear bodywork:




(#1 on the left, #2 on the right)

Another one of the #2:


New front fender does away with the 'kink' from the side profile, and the trailing edge of the rear deck has a different shape.

[gwyllion]

@cdsavage: I think you are right. It is much easier to spot the difference on these high resolution pictures: https://picasaweb.google.com/1030266...283/AudiR18TDI

[The Badger]

Yeah , the firts pic , it linda looks more splayed , while the rear has a lower centre area .

Wonder whats what ?

[gwyllion]

http://www.422race.com/2011/le-foto-...-audi-a-monza/ also reports about the Monza test.

Pictures of the Monza test can be found on the following website:
http://www.motorsportuniverse.com/AudiR18.html
https://picasaweb.google.com/1030266...283/AudiR18TDI
http://www.422race.com/foto/?g_id=736

[gwyllion]

Another PR article from Audi Sport: Climatic wind tunnel helps Audi at Le Mans

In the climatic wind tunnel ventilation of the closed cockpit was optimized to such an extent that the R18 TDI will manage without air-conditioning at Le Mans. As this costs both weight and power the engineers were happy to exclude the use of such a system. The deposit of rain water or solid materials such as sand, rubber pick-up and stones was also simulated. “We made many valuable discoveries in this area on the full scale car in the climatic wind tunnel and modified several things and especially in the airflow area,” says Dr. Martin Mühlmeier. “The reflective film on the roof was also validated with findings from the climatic wind tunnel. These are all important details to guarantee a good climate around the driver in the cockpit.”
...
The screen is heated to prevent fogging. For possible soiling a three-stage plan was developed which, subject to the level of soiling, allows for simple wiping, wiping with detergent or the removal of one of several layers of rip-off films.

[chernaudi]

Maybe the climatic windtunnel didn't go a good enough job simulating tire debris, but then again, it's a windtunnel, not a rolling road or track surface.

I didn't really notice that the front end of the R18 changed much aside from the fact that it seems that some changes were made to the profile of the front fenders.

The rear deck is more noticeable, and seems to be modeled on the LM 908 variant's. Maybe Audi is testing to see if one or the other setup is better for LM.

Audi also used a water truck (like Peugeot) to water down the track late in their test session.

[gwyllion]

Originally Posted by chernaudi

Maybe the climatic windtunnel didn't go a good enough job simulating tire debris, but then again, it's a windtunnel, not a rolling road or track surface.

The tunnel gave them "valuable findings for cockpit, windscreen and windscreen wiper". There is no mention of it being used to test the impact of debris on the radiators, intercoolers, brake cooling, tyre pickup, ...

As you can see on http://endurance-info.com/version2/i...soufflerie.jpg the car is stationary. The wheels don't rotate and the engine is probably not on either.