Audi LMP1 Discussion

[chernaudi]

If we're talking a 1:44, which is number gleaned from an ALMS fan forum posting, then on ALMS style tracks, the newer LMP1s probably won't be too much slower than the older cars.

It's at Le Mans and other places such as Monza where straightline speed is a premium where we'll see major drop off.

But then again, what was the rumored 1:44 time for--the R15 or the R18, which I guess based on power/torque alone there shouldn't be much of a difference?

But then again, a 2009 spec R15 with a 2010 spec engine package ran a 1:43 last year in a test at Sebring. With the R15 being in a sprint race package and the R18's being in what seems to be an LM areo layout, if it was the R18 being quoted as running a 1:44, then it should be faster with a HD areo kit at a typical ALMS/ILMC track, and about as fast as the older cars.

[Bentley03]

Originally Posted by JAG

On the ALMS forum someone said the R18 did a 1.44.

For reference, Sarrazin peddled a 908 around Sebring in 1:42.801 at the Winter Test Days in 2008.

During race week in 2010, the lack of competition was presumably the reason neither Peugeot bettered a 1:44.972 and in 2009, the quickest lap by an R15 was a 1:44.147 (but bettered by Peugeot with a 1:43.274).

Chernaudi, was the 1:43 R15 lap in testing last year ever verified (published or quoted by someone within Audi)?

[chernaudi]

Originally Posted by Bentley03

For reference, Sarrazin peddled a 908 around Sebring in 1:42.801 at the Winter Test Days in 2008.

During race week in 2010, the lack of competition was presumably the reason neither Peugeot bettered a 1:44.972 and in 2009, the quickest lap by an R15 was a 1:44.147 (but bettered by Peugeot with a 1:43.274).

Chernaudi, was the 1:43 R15 lap in testing last year ever verified (published or quoted by someone within Audi)?

The 1:43 by the R15 last year in Sebring was during a private test by Audi, and it was a 1:43.8, was quoted by Marshall Pruett last spring after the 12 Hours, and was gleaned from either an Audi team member or someone who bothered to take a stop watch.

It should be noted that it was a 2009 car with the 2010 engine. Also, during an ALMS practice session in '09, a R15 ran an offical lap of a 1:43.5.

If the R18 ran a 1:44, that's an encouraging sign thus far, but not entirely unexpected--an Audi R8 could probably run that now with a similar power setting.

And if the R15 can run similar times, all might not be lost for Audi at Sebring.

And that's also so much for the extra 75kgs that new LMP1s have to carry compared to LMP2s of previous years.

Then again, the R18 should be making power and torque comparable to the old R8 of '03-06 in ALMS spec. So times should be similar to what hypothetically that the R8 could run in similar conditions and specs.

[hcl123]

Originally Posted by gwyllion

Perhaps they should have told Peugeot not the run the 90X before Le Mans

If the ACO is unhappy with the pace of diesel in Spa and during the test days, they can still adjust the performance balance.

Ppl write this things nowadays like if it were the the most normal of things !!!!!

I'm almost 50 years old, been in sports most of the time, loved motorsport ... and i've never hurd or seen such ludicrous presumptions and attitudes and ANTI-SPORTIVE measures of a regulatory body like in recent years by ACO...

why wouldn't they tell us "who" they want to be winning so we can go home ?

rules that arbitrarily can be changed are not rules at all.. the law can change but this is like the police changing the law when and where they please the most. This is not sport this is "sig heil!" all over again, and the beauty of Lemans that was/are the "prototypes" is going to be lost...i used to love it, many different solutions with different engines bodyworks etc etc etc AND DIFFERENT PERFORMANCE = ITS ONLY NATURAL, but now ACO wants to transform it into a lame "throphy car" race where everything must be the same!!...

If they change rules arbitrarily again i'm switching off... and trophy races only assist the wifes of the pilots.. that is the fate expecting ACO...

[hcl123]

Originally Posted by chernaudi

Getting back to the R15 vs R18, we gotta remember that the R15 still has a 1.8 liter advantage, and displacement=torque, just as forced induction means more torque. Of course, the larger displacement threortically means inferior fuel comsumption unless the R15 ends up being a very low-revving engine due to the restrictor/turbo boost changes.

no! torque is a relation of the relative "presure" inside a cylinder during the power strokes.. meaning you can have a much smaller cylinder that generates and sustains much more relative "pressure" than a much larger one.. and so an engine on those smaller cylinders (with more pressure) has a much smaller displacement than a bigger engine(but with less relative "pressure")... yet it produces much more torque.

That is why forced induction generally means more torque = more "pressure".

Fuel consumption has to do with efficiency measured in the "carnot cycle"... and a larger "volume" is more difficult to "heat up" for efficient pressure inside than a smaller one... during those power strokes... so the larger the volume the worst the fuel consumption (theorectically)...

engine revs has to do with the balance of the engine and with reducing parasitic loads and attrition... meaning the higher the relative "pressure" you have inside a cylinder, the more robust and heavy(attrition) it must be, the more parasitic loads it can potentially generate, the more difficult is to balance the all thing ... ( this is is the difference between the V12 of Pug and a F1 engine = a big carnot efficient of brute force vs a very light and agile gas guzzler ballerina; HINT - > you can't tell by the sound! )

Don't mark me off topic... i'm trying to help... clear misleading assumptions...

Bottom line it depends of many things and surely is not easy... and it will take lots of time of development... but there is nothing to say that could prevent a V6 3.7l to have even more torque and more power than a V12 5.5l that stopped being developed.

[Sebring 1:43]

I was told that the R18 routinely ran in the 1:46's @ Sebring. Anything faster was not observed by my sources.

Enjoy the appetizer.......aka the 24 Hours of Daytona

[hcl123]

Originally Posted by gwyllion

Personally I doubt that the R15 will have a huge torque advantage. You must remember that the ACO has reduced the turbo pressure considerably: from 2590 mbar to 2000 mbar (i.e. 23%). Assumping a linear reduction, this corresponds with a reduction from 1100 Nm to 850 Nm.

I agree it will take time to develop.. nevertheless it was in this forum, a rumor that the V12 or Pug could reach up to 1400nm, and this more than 1 year ago... so 1400nm -23% = 1138nm...

but this is theory... it will take more years before a V6 reaching the levels of a V10 in torque( if its not stopped), because they can have the same torque per cylinder, i.e., the same "force" down per power stroke, but a V10 has 5 of those per revolution of the crankshaft and the V6 only 3... the same acceleration is out of the question for this year, but a V6 can rev much higher if well balanced consuming even so, relatively less, and so the top power HP (it has to do you the speed of the crankshaft) can be identical( the least of the goodies!!).

[hcl123]

Originally Posted by gwyllion

That is elementary physics. For a given number of revolutions per minute, a engine with larger displacement sucks more air and hence produces more torque.

However, the ACO does not regulate the amount of torque that different engine configuration makes. They only care about the power that engines produce. This is where the air restrictor comes in place. The restrictor chokes the air and hence restricts how high an engine can rev. Remember power = torque x rotational speed (see wikipedia).

No the restrictores reduce power by reducing torque (power=torquexspeed).. that is what ACO wanted.. the beauty against the "sig heils" is that a diesel is compression ignition, so they can always play with compression rates and more efficient intake air routing...to the point that last year they officially announced in an imperial decree, in a relative few time before the race.. to ARBITRARILY play the restrictor & weight game again...

..."its wise" they said... "below 3.20 its getting too dangerous" they said (why don't they tell the truth that what was deliberated was to f**k the diesel.. again!), "we foresee it will reduce up to 15% of the performance" they said in their infinite wisdom! ( SPECIALLY OF THE DIESELS of course!).. yet the diesels, specially the diesels made the fastest race ever, with the lap record of 3.19 flat after more than 20 hours of race(could be less if the Pugs haven't broke) !!... and no one dead!

So for a body that has the "wisdom" so to speak (15% less performance hein!?)... what was proved is that they don't know what they are doing...

[chernaudi]

Originally Posted by Sebring 1:43

I was told that the R18 routinely ran in the 1:46's @ Sebring. Anything faster was not observed by my sources.

Enjoy the appetizer.......aka the 24 Hours of Daytona

That means that if anything ran the stated 1:44 lap time, it was probably the R15, which is understandable--it's older, so it's more developed, and the R15 had a full sprint race areo kit on it, while the R18s were basically equipped with an LM aero set up. IE, expect a taller rear wing/fin (in the side profile photos, it's obvious that there's a drop down from the fin-like extension on the engine intake and the rear deck section of the fin) and larger dive planes on the sprint version of the R18.

But then again, the 1:44 was sourced from the ALMS forum, so it could pertain to the R15, the R18, or could be an inaccurate time altogether. I haven't seen here which car supposidly ran that time.

[JAG]

They were talking about the R18.

R18 fast lap was around 1:44. most laps were in between that and 1:48

ORECA today said they were running the 908 this year, they admit they'll be focusing on reliability because grandfathered cars will not have the pace of purpose built 2011 machines.

Reg changes only really affect power, aero, chassis, tyres and the general efficiency of the car should all be improved over a 2010 car.

[chernaudi]

Audi and Oreca are probably safe bets for a good result at Sebring, because there's no way a this stage that the R15 and the 908 will be much slower than the R18 or the 90X. Same power and torque as the newer cars, but the 30kgs might hurt them as far as weight (newer cars will have to weigh 900kgs min, while the R15 and the 908 will have to weight 930kgs as far as is known).

But then again, 1:44-1:48 was the range of laptimes that the 908 ran on average last year, and I don't see that changing. So the R18 and maybe the 90x will be on pace with the older cars clearly. However, I do expect the R18 and the 90X to gather speed as they have more room for development work, while the R15 and the 908 are nearly at the end of their life cycle, and the 3.7 diesels should be fairly reliable, since we're talking engines that won't rev much above 5K RPM and are restricted to 2003 LMP1 power levels.

However, in theory, that should make the R15 and the 908 neigh high bullet proof as well.

[CTD]

What we most remember is that the 908 from last year is with the cracking piston rods. And i do not believe that Peugeot will use them again this year (unless they have beefed them up, enough)

[Audi Racer]

The article is on it's way. Marshall says that he has to get home from the 24 at daytona and then get the scoop on the audi sebring test that happened last week first.

[chernaudi]

That's good news, and the more info, the better at this stage.

Don't look for Audi to verify the laptimes that either the R18s or the R15 ran, though...

[Lppiesaudi]

More Photos surface: http://www.flickr.com/photos/lemansl...th/5404670292/ these look like Audi Press Photos. Nice photo with The R15 plus and the R18, the R18 is so much smaller than the R15...

[chernaudi]

Check Mike's site--the R18 is not much smaller than the R15--the shorter wheelbase on the R18 is partly made up for by longer front/rear overhangs.

Also, I found this on AudiWorld, authored, Ironically, by Audi of America:

http://www.audiworld.com/news/11/r18-test/

[gwyllion]

Originally Posted by Lppiesaudi

More Photos surface: http://www.flickr.com/photos/lemansl...th/5404670292/ these look like Audi Press Photos.

They are. Official press release on http://www.audi.com/com/brand/en/exp..._test_for.html

Apparently one R18 and the R15 were doing long runs and the other R18 did development work.

[MulsanneMike]

BTW, let me call BS to those suggesting the R18 isn't in "high" downforce specification. What makes one think that isn't the case to begin with? Because it only has one set of diveplanes? See, the visual reference is back to the R15. But that can't be the bench mark. With ultimately less horsepower the R18 is designed to a different aerodynamic philosophy, one looking at higher L/D efficiency and less total downforce.

But even so, the statement doesn't pass the sniff test inasmuch as if we're assuming a "high" DF kit would include a higher rear wing height; rear wing mounts are relatively easy to manufacture in the scheme of things and there's no good reason why Audi would trundle around Sebring in the wrong aero setup to begin with. You'd learn zero.

[MulsanneMike]

Originally Posted by Lppiesaudi

More Photos surface: http://www.flickr.com/photos/lemansl...th/5404670292/ these look like Audi Press Photos. Nice photo with The R15 plus and the R18, the R18 is so much smaller than the R15...

Yes, I see what you mean. I think the height of the nosebox on the R18 is lower than the R15. I'm not talking about at the leading edge of the nose, I'm talking about where it intersects with the driver; the overall "shoulder" height of the tub is lower. Compare the top of the tub where it intersects with the glass to the tops of the wheels. And then look at that same approximate relationship on the R15; R15 is taller in that area by a lot. But of course the tops of the fenders are nearly the same on both cars, so overall I don't think the R18 is much, if any, smaller from a frontal area perspective. I think that impression is heavily driven by the visual references I point out.

[gucom]

^ that was also quoted by Dome as an important advantage of a closed-top car, when they introduced the S102:

due to the lower roll over structure at the front of the cockpit, a coupe car can archive a much lower driver position than a open car” explains Dome’s Hiroshi Yuchi “roadsters or open cars have a much higher structure ahead of the driver. In addition to that the rear roll structure mandated for coupes is lower than that for roadster, which can allow, even with the roof structure for the closed cars to have a lower centre of gravity.”

http://www.racecar-engineering.com/a...s/dome-s102-4/

[chernaudi]

Well, explain this--the R18's deck fin drops down from the back of the tub, where there's an extension that's horizontal that starts from the rear of the engine intake, but in the break from the tub to the rear deck, the fin drops down to the wing mount pylon. Design flaw? I don't think so. I think that Audi probably has a taller wing pylon for sprint race trim, and hence, a higher wing and a taller fin with a horizontal top.

And what can we make of the numerous, and if Mike's correct, seemingly redundant holes in the nose above and below the tiny diveplanes that they're running? Audi's aero guy would be just an ideot to drill useless holes in the nose of the car just for the sake of drilling holes.

The R8, when it got hit with a 60-100bhp reduction from '02 to '03, they didn't alter the aero package until the ACO told them to due to the rear wingspan reduction. However, did the sprint diveplanes go? Nope. And the R18 makes the same power and torque on paper as that version of the R8 did.

And LMP2s, which made the same power as current LMP1s on paper, ran as aggressive if not more aggressive (especially Acura) HD areo than the LMP1s usually did.

Only reason why the R18 in my opinion could be in sprint race spec is if the front diffuser, having to be more aggressive to counter downforce losses from interactions with the front tires, makes a ton more downforce compared to the R15, which may be true to an extent, but not that far.

And Audi test the R15 with sprint race aero until a practice session at Paul Ricard, which I've said before was a rather intresting choice, as teams tend to test for their LM packages there, and didn't race that aero until Silverstone.

Sebring was the R18's first major test, so it stands to reason that Audi doesn't have the "latest and greatest" aero stuff for it yet. In the coming weeks and months, that'll come out I have little doubt.

As I said, LMP2s ran with more aggressive areo than any LMP1s, save for the Acura ARX-02, and LMP1s have been pegged back to similar power levels, and I don't think that these guys, like in '03, are willing to give up aero grip and downforce for sprint races, unless the track is like Monza, perhaps Road America, or any place where downforce isn't a major concern.

As for size comparisons, the R18's roof/rollover structures might be lower, but the big reason for that illusion is that right now at least the R18's wing is mounted so low. If the fin/wing max height is governed by airbox height, than the R18 will still have a lower wing, but not my much in sprint race trim.

[MihokS5]

Does anyone have high res shots of the Audi Motorsport photos that they released? The Audiworld ones are the only ones I've seen:

http://www.audiworld.com/news/11/r18-test/

[gwyllion]

On the flickr link that was posted earlier, you can download them in 3840 x 2560:
http://farm6.static.flickr.com/5017/...d4a294_o_d.jpg
http://farm6.static.flickr.com/5131/...76feac_o_d.jpg

[MulsanneMike]

Originally Posted by chernaudi

Well, explain this--the R18's deck fin drops down from the back of the tub, where there's an extension that's horizontal that starts from the rear of the engine intake, but in the break from the tub to the rear deck, the fin drops down to the wing mount pylon. Design flaw? I don't think so. I think that Audi probably has a taller wing pylon for sprint race trim, and hence, a higher wing and a taller fin with a horizontal top.

And what can we make of the numerous, and if Mike's correct, seemingly redundant holes in the nose above and below the tiny diveplanes that they're running? Audi's aero guy would be just an ideot to drill useless holes in the nose of the car just for the sake of drilling holes.

The R8, when it got hit with a 60-100bhp reduction from '02 to '03, they didn't alter the aero package until the ACO told them to due to the rear wingspan reduction. However, did the sprint diveplanes go? Nope. And the R18 makes the same power and torque on paper as that version of the R8 did.

And LMP2s, which made the same power as current LMP1s on paper, ran as aggressive if not more aggressive (especially Acura) HD areo than the LMP1s usually did.

Only reason why the R18 in my opinion could be in sprint race spec is if the front diffuser, having to be more aggressive to counter downforce losses from interactions with the front tires, makes a ton more downforce compared to the R15, which may be true to an extent, but not that far.

And Audi test the R15 with sprint race aero until a practice session at Paul Ricard, which I've said before was a rather intresting choice, as teams tend to test for their LM packages there, and didn't race that aero until Silverstone.

Sebring was the R18's first major test, so it stands to reason that Audi doesn't have the "latest and greatest" aero stuff for it yet. In the coming weeks and months, that'll come out I have little doubt.

As I said, LMP2s ran with more aggressive areo than any LMP1s, save for the Acura ARX-02, and LMP1s have been pegged back to similar power levels, and I don't think that these guys, like in '03, are willing to give up aero grip and downforce for sprint races, unless the track is like Monza, perhaps Road America, or any place where downforce isn't a major concern.

As for size comparisons, the R18's roof/rollover structures might be lower, but the big reason for that illusion is that right now at least the R18's wing is mounted so low. If the fin/wing max height is governed by airbox height, than the R18 will still have a lower wing, but not my much in sprint race trim.

That the R18's fin isn't parallel to the reference plane is neither here nor there, the regulation simply states:

The top edge must be straight and situated between 920mm
and 1030mm above the reference plane



Regarding the dive planes; the Audi's front fenders have been designed to move air around them, as opposed to over. The diveplane is very aggressive being mounted nearly on centerline with a trailing edge that is offset to the face of the fender, not parallel to it as on the R15. It would shed a pretty strong vortex off it's TE, especially so given the amount of flow it's seeing. I suspect there might be some very interesting interaction between the vortex flow off the diveplane TE and the front diffuser. That there's another position drilled out isn't surprising; verify the wind tunnel position in full scale. If they've designed the diveplane to work as I've described it, then they would do just that. Not to mention, the hole positions appear on top of one another or nearly so. You'd never locate diveplanes right on top of one another like that.

Additionally, I'm told CFD cases show big gains in DF with lowered wing position. But this only becomes interesting if you're now concerned with drag; I'm not convinced there's a higher wing position, yet at least. The twin-tier rear wings used in IMSA GTP came about because, while the lower position interacted with the tunnel exits beneficially, there was a diminishing return when you were looking for maximum downforce, to hell with drag. That is, they peaked out, and to gain more total you had to go high with the wing and at that point you lost all the good L/D from the lower position. But in IMSA you didn't care about drag as the street circuits were slow (top speed-wise) and you weren't running to a fuel formula. Thus now, with smaller fuel tanks and less power, you're vastly more concerned with taking drag out and making efficient use of what drag you are generating. Again, you can't look back and use the R15 as a reference for concept; you're going to design it different if you know you only have 550 hp vs having 700.

[Audi Racer]

Originally Posted by MulsanneMike

BTW, let me call BS to those suggesting the R18 isn't in "high" downforce specification. What makes one think that isn't the case to begin with? Because it only has one set of diveplanes? See, the visual reference is back to the R15. But that can't be the bench mark. With ultimately less horsepower the R18 is designed to a different aerodynamic philosophy, one looking at higher L/D efficiency and less total downforce.

But even so, the statement doesn't pass the sniff test inasmuch as if we're assuming a "high" DF kit would include a higher rear wing height; rear wing mounts are relatively easy to manufacture in the scheme of things and there's no good reason why Audi would trundle around Sebring in the wrong aero setup to begin with. You'd learn zero.

Don't get the impression that Audi isn't stubborn. The Audi R18 has no intention of running at sebring or any alms except petit for that matter. Please remember that Audi did the low downforce thing at spa last year and believe me if your going to run low downforce at SPA!!! Yes the spa francorchamps track in belgium.then you can probably get away with it at sebring. Also take reference to the peugeot 90X picture we last saw. the wing in that photo is pretty high and the fin is straight. I think theres more to that than what i am suggesting about the peugeot and audi differences but don;t take audi for granted. they've gotten into the habit of being lemas focused even if that meant running no downforce at a track like monaco.