Audi LMP1 Discussion

[hcl123]

Originally Posted by chernaudi

Biggest issue for Audi is that they need power breaks, and under the current EOT-based BOP, the "easiest" way is to run more hybrid power.

Problem for Audi is that especially 6MJ or above will result in an overweight car.

Not necessarily... the problem is that with 6MJ they would have even less fuel ratios to use... they could downsize the engine... or they could maintain the same displacement but make it rev lower(use less fuel per rev)... or they could preheat the fuel before injection, and redesign and coat the combustion chambers with the proper thin films (high hidro /lipophobic material for the head, carbon diamond coating for the cylinder walls ), and shave weight elsewhere... but could any of it achieve the same power envelops ? (the last solution most probably with considerable less fuel for more power not the same... but horribly expensive to develop)

Its all about the fuel ... all power comes from the fuel ... air restrictors are kind of much easier to overcame by 'forced induction' systems... but fuel, now you have to make your engine more efficient no matter what,i.e., same power for less fuel (and it has been quite an evolution... 100%... or half the fuel for the same power envelops comparing the first big V12 diesels with the now V6).

Originally Posted by chernaudi

However, as of now, Toyota and Porsche are in the same boat; even Porsche, who used batter technology with a car under the 870kg limit prior to adding ballast will take a hit on weight if they go to 8MJ if they can't lighten the car.

And getting back to the future, if Audi and Toyota go to battery based storage systems, that for sure will add weight

IIRC the past rule discussions and FIA/ACO documents all cars need to have at least a minium ballast in determines points... so all cars without ballast are already less than 870kg !?

Originally Posted by chernaudi

Another issue with inline 4 engines is that they're difficult to make into a fully stress mounted engine. Only Audi's Ulrich Baretzky managed that with the old 1990's VW F3 engine, and no one's found out his secret.

Perhaps no one haven't bothered yet... 'inline' its not the best solution for weight distribution, makes gravity center higher...

Originally Posted by chernaudi

Fact is that the current EOT BOP doesn't seem to favor diesel technology from a power to weight ratio standpoint as much as the old air restrictor BOP did. And in real life, diesel engines do have a relatively low power to weight ratio without forced induction. The reason being an issue intrinsic to diesel engines--that, simply put, they can't rev freely like a gasoline engine can.

clearly doesn't favor diesel from an energetic point of view...

there is at least a 7% exogenous factor in the overall accounts for fuel ratios (a factor for compensating the superior thermodynamic efficiency of diesel!!...
(which is a logic contradiction about the efficiency mantra, as if diesel advantage in this respect is unnatural and illegal (LOL) )...

and tank capacity is 22% less for diesel which exacerbates the issue...

and even more exacerbating because petrol users can dope with additives their fuel supply for protecting their engines, while diesel must be used as is...
(another balancing factor so that petrol can withstand 24h at full load, because they rev much higher so wear is higher ... but with it a "charade", because i'm certain if they bothered to measure(by surprise), specially at 'sprint races', than now its petrol that has more MJ/ 'kg of fuel' than diesel (sprint races don't need much wear protection, but petrol for sure could use a little more energy content... at the small number of laps qualifying sessions even less of a problem ... so ...)

Originally Posted by chernaudi

Just look at peak power RPM: Toyota had a rev limit of 8500 rpm this year, Porsche, about 8000, Audi, 4500 rpm.

Diesels can't make top end power based on rpm because beyond about 4500-5500 rpm, they don't make power because that range is the max where compression ignition is at it's most efficient as far as top end power.

Hence, as pointed out, diesel engines need larger displacement and forced induction to make power. Just like how small engines are handicapped by having small capacity and having to rely on revs to make power without forced induction

Well good points... but it think its not there is necessarly an inherent drop of power of the diesel tech at those revs levels (though in many current diesel engine designs it seems there is)... its more like fuel ratio penalties would hurt badly... and then to make the same 13 14 lap stints ( Le Mans example) as petrol, would make it quite an impossible exercise derived from the 22% lower tank capacity ( i think the drivers for themselves will be more than glad to show with how many sticks one makes a canoe lol)

Bottom line ... they got diesel by the balls...

Originally Posted by chernaudi

Problem is that even if Toyota are right that a bigger NA V8 is favored by the current regs, you're still gonna have a relatively heavy engine even by modern standards because of how NA engines make power though a combination of rpm and displacement. And 4 cylinder turbo engines may be smaller, but the turbo systems add weight.

Sure turbo adds weight... but to the point of making a V4 package heavier than a V8 package... i think its quite unproven that statement...

Originally Posted by chernaudi

Basically, there's no perfect or totally ideal solutions that don't have some drawback to them. But the EOT should make it so teams can balance engine and hybrid power to get a good package and not have a crippling disadvantage.

Hence, why Audi might be willing to take some weight penalty to get more power--the old Peugeot 908 HDI-FAP was often very much over the 900kg minimum weight, but that didn't slow it down. Maybe Audi--and others--might adopt that logic if overall car performance improves.

Ppl screamed about tech equivalences ruling ( not scientific equivalences)... so they *must* cripple the best, because making a worst tech perform at the levels of a better one, can't be done by political decree, only by scientific improvements.

The 908 of 2010 had 925kg if not mistaken... and holds the lap record of La Sathre with 1.19.00(or 0x IIIRC), curiously achieved after ~20h of race, not in any qualifying session... more words for what...

still far from perfect of what possible...

today still many years of development is needed again ( never say never)... any such attempts to revive today that 'logic' would result in a shower of fuel ratio penalties ( making it a poor logic..)

[hcl123]

Originally Posted by MyNameIsNigel

I do expect that there is still some performance to squeeze from the V6 TDI in terms of further improvements in engine efficiency. The current efficiency target for diesel is estimated to be of approximately 44.5% (assuming a target of 41.3% for petrol). The fuel allocation for diesel (in the 2 to 6 MJ ERS classes) is in excess of 130 MJ/lap, meaning close to or slightly less than 60 MJ/lap of useful energy.

If Audi can improve efficiency, that should also put them back in the game... unless Toyota and/or Porsche can achieve similar efficicency improvements on the engine side.

If 2015 is the last year of diesel in endurance racing, Audi could however be more radical on the engine side and push the limits.

That's what I am hoping for at least.

So, ultimately, I would expect Audi to make a step up to the 4 MJ/lap ERS class and work hard on improving efficiency to beat the current EoT target. If Audi can make it up to the 6 MJ/lap ERS class, then fine.

EDIT: Is it unrealistic to believe that Audi could achieve improvements in efficiency of the order of few percents, e.g. an efficiency of 46% or more ?

why not ? ... if you read the regulation thread and see the FIA/ACO tables, from 2Mj to 4 MJ is only ~3.5% of difference... for 6MJ is 7%... they said they achieved already 40% more compared with the last V12( i think) ... if they take out the particulate filter, and see no smoke then diesel as sorted out of the adolescence in motorsport (if not everywhere)... no smoke with no filters, something very efficient and powerful has been achieved... but i think it will be dead before that...

[Articus]

Originally Posted by hcl123

The 908 of 2010 had 925kg if not mistaken... and holds the lap record of La Sathre with 1.19.00(or 0x IIIRC), curiously achieved after ~20h of race, not in any qualifying session... more words for what...

I don't think I've ever gotten over the pace of the 908. Not even factory driver at the wheel. Not even a factory car.

[hcl123]

Originally Posted by carbon_titanium

Only about 800Nm as torque peak? well for me it simply doesn't exist... C6R GT1 had more than that. To me is simply unbeliaveable, also because of the larger displacement compared to 2011-2013.
I think that the diesel engine pushes not less than 1000Nm during the peak! also because doing a quick calculation, to develope 540hp@4500rpm as the article reports, are required not less than 855Nm. More than the 600lbft (813Nm) that the article reports... and we all know that diesel reaches his torque peak very early in the rpm range.

(Nm*6.28*rpm)/60 (result will be in W, so / 1000 = KW. Value in KW*1.34 = Value in hp)

(Watching the onboard telemetry, the R18 e-tron revlimit is 4500rpm)


PS Dindo Capello has the R18 TDI (the chassis that won at sebring 2012 if am not wrong or a replica of that car) in his audi dealership. Of course the real owner of the car is still audi, not Capello.

All this diesel engines tend to achieve the torque peak very earlier... potential acceleration beasts... but it could be engineered to plateau along the most used and or advantageous usage band ... and that is only a "domestic version" ( no ~500hp car with 870kg would do 3.22min at Le Mans (doubt)

[TF110]

Originally Posted by Articus

I don't think I've ever gotten over the pace of the 908. Not even factory driver at the wheel. Not even a factory car.

I think they made Audi look like they were lacking in the engine department in terms of power. Maybe reliability is questionable on Peugeot's side vs Audi. I think looking back, they were the benchmark on what diesel could achieve, at least in terms of power. 2011 was one of the best showcases of what the difference was between them under new rules. Le Mans was a great race that year.

[hcl123]

Originally Posted by Articus

I don't think I've ever gotten over the pace of the 908. Not even factory driver at the wheel. Not even a factory car.

oops!.. there is a typo... the 908 time is 3.19.0x at La Sathre... i think less than 2 minutes is literally impossible lol ...

Nevertheless, IIRC it is still the lap record for the circuit.

[Deleted]

If someone would ask me what do you think was the most brutally powerful car at Le Mans this century, I wouldn't even think of Audi, Toyota, Porsche, Bentley or others (same goes for the 1000bhp hybrids etc)... the Pugs were just something else, even if it only materialized for win once

[hcl123]

Originally Posted by TF110

I think they made Audi look like they were lacking in the engine department in terms of power. Maybe reliability is questionable on Peugeot's side vs Audi. I think looking back, they were the benchmark on what diesel could achieve, at least in terms of power. 2011 was one of the best showcases of what the difference was between them under new rules. Le Mans was a great race that year.

A lot as to do with proper scale of gear ratios and engine mapping.

If we speak of "power" in terms of 'top' numbers achievable, even by then the Aston Martin V12 had more power than any of the diesels... yet could lose seconds in a lap... because to achieve those higher top *power* numbers at double or more the RPM, it takes time(some engines more than others)... and is this in-between time, that reflects badly on the lap scoring... meaning is much better an engine with less top power but that drives most of time near that top power band, and transition very fast (if the diff in RPM from low to top power is much reduced the better), than an engine with much top power but that takes a lot of more time to achieve that top power bands.

That was the principal advantage of the 908 V12 diesel, by then (even comparing a V12 to a V10 diesel).

[hcl123]

Originally Posted by Chiana

If someone would ask me what do you think was the most brutally powerful car at Le Mans this century, I wouldn't even think of Audi, Toyota, Porsche, Bentley or others (same goes for the 1000bhp hybrids etc)... the Pugs were just something else, even if it only materialized for win once

In a sense those *possible bhp* numbers have a lot to do with advertising, they are possible but irrelevant in most of the issues, as an indicative of overall performance.

Yet 'Hybrid' or the introduction of electric motors, just reshuffles the deck. Now the time in-between low and top powers levels of the engine is much much less relevant, if the electric motors plays a good part in covering the slack.

And is this factor, coupled with how much electric energy you have to play with, that has been the principal advantage of Toyota (though they may have others). The Toyota hybrid system is clearly above the competition.

[sssssssss]

Originally Posted by Articus

I don't think I've ever gotten over the pace of the 908. Not even factory driver at the wheel. Not even a factory car.

well in 2011 the audi r18 showed faster pace than the peugeot 908. the audis were faster both in qualifying and in the race. and that was just the very first version of the r18 and the most evolved version of the 908.

[Deleted]

Think he means the previous 908 HDI FAP - and before ACO force slowened down the P1s. I know I do

[carbon_titanium]

Originally Posted by sssssssss

well in 2011 the audi r18 showed faster pace than the peugeot 908. the audis were faster both in qualifying and in the race. and that was just the very first version of the r18 and the most evolved version of the 908.

disagree at all... both 2011 R18 TDI and 2011 908 were the first versions of their car generation. During 2012 an 2013, R18 was updated and upgraded a lot, but even if peugeot withdrawn from LM in early 2012, it was already produced an updated not hybrid 2012 version of the 908 and the 2012 hybrid model: 908 Hybrid4.
Peugeot shown to be better than Audi for the whole 2011... at LM audi was forced to use more power than usual with a more high drag/downforce package compared to the low drag 908 design... in qualifying the best R18 was just 0.27s faster than the fastest 908! but audi paid this choice with a worse fuel miliage!!!
#7 was going to win, if wurz didn't crash at indianapolis.

I don't speak at all about the 2010 908HDi used by oreca in 2011 ILMC, because it was insanely detuned... just to say: same LD package at le mans, in 2011 barely was able to hit 325km/h, when in 2010 easily could touch 340km/h and on...

[cokata]

The '08 and '10 Peugeots were monsters, too bad both had unknown faults at the time that prevented them from winning.

[J Jay]

I thought the 2010 908s had those conrod failures that were specific to the batch of LM engines and no others. And the only car that wasn't affected was already out because its tub had been too badly damaged in a shunt.

Those cars had enough torque to restart the planet and still lap la Sarthe in under 3:30!

[carbon_titanium]

No doubt that peugeot 908HDi has been the most powerfull and most competitive LMP (or overall sportscars) ever built so far! over 1200Nm and over 750HP in 2008 and 2010!

Who knows if 2015 work lmp1 will be able to run under 3.20 during qualifying

[DistortedSmile]

Originally Posted by hcl123

oops!.. there is a typo... the 908 time is 3.19.0x at La Sathre... i think less than 2 minutes is literally impossible lol ...

Nevertheless, IIRC it is still the lap record for the circuit.

The lap record is actually from the '08 Pug with a 3:18.513 in qualifying.

Originally Posted by carbon_titanium

No doubt that peugeot 908HDi has been the most powerfull and most competitive LMP (or overall sportscars) ever built so far! over 1200Nm and over 750HP in 2008 and 2010!

Who knows if 2015 work lmp1 will be able to run under 3.20 during qualifying

I remember Wurz in a Toyota interview, saying that the 908 was actually north of 900hp or something like that.

[TF110]

800hp iirc. I was happy when he said that because it proved just how lopsided the rules were in diesel's favor. To be putting out that much power and still match and exceed Aston Martin, Dome etc. in stint lengths is crazy.

[hcl123]

Originally Posted by TF110

800hp iirc. I was happy when he said that because it proved just how lopsided the rules were in diesel's favor. To be putting out that much power and still match and exceed Aston Martin, Dome etc. in stint lengths is crazy.

Oh! c'mon ... when similar leaks of 3L F1 engines puts them north of 1000hp... do you believe the power numbers officially stated is the real numbers ? ... 2014 Toyota engine only does 500 hp or so... less than a road going Ferrari ...yaeh! right!, poor guys, if they ever race against a road going Ferrari we have to do something to restrain the Ferrari...

Sorry for the sarcasm, but its illustrative. *No* was not unfair, was better, like Otto engines were better than steam engines, and in reality, in potential, i believe diesels engines will never in the foreseeable future be able to advertise higher HP numbers than comparable petrol engines, because at most (6500RPM that i know) they are at least 3x slower in the reving than petrol equivalents...

Yet those power numbers are completely irrelevant in great extent... the oscillation from low power to high power is more important, and the medium power usage(as express before)... and was in there the greatest advantage of diesel, its usage power band in between 2K and 4 K RPM with north of 1000 Nm (for the V12) was unbeatable...not the *top* power number...

To have a notion of the fairness, just remember that a 2L at 10K RPM, has the same working volume per unit of time than a 4L at 5K RPM (6L at 10K RPM of Aston Martin, should be equivalent to ~15L(not 5.5) at 4K RPM) , there isn't any a priory unfairness in this, it depends on how energetic and efficient the combustion inside a cylinder is ( in a word better)... and is not a fault of a fuel being more energetic than others, specially if its available to everybody.

Sincerely, i will die of hold age without understanding the mentality of the passions... of why that things like being a fun of "something" ( like a football team, a motorsport team, a brand, even a nationality or a religion) is a logic that makes ppl irrational... just because something else is better than your *passion* something doesn't mean its unfair, or not proper, or illegal...

[kaseo88]

Hi,

Maybe someone could be still interested in this pic of the front bulk of the R18 that I took at LM pitwalk:

http://oi59.tinypic.com/2rm74zk.jpg

[MyNameIsNigel]

Originally Posted by kaseo88

Hi,

Maybe someone could be still interested in this pic of the front bulk of the R18 that I took at LM pitwalk:

http://oi59.tinypic.com/2rm74zk.jpg

Thanks for posting. A rare look at the front bulkhead where packaging is quite tight indeed. Racecar-engineering have a picture of the other half of the front bulkhead BTW:


It's quite interesting to see the evolutions of that part over the years.
Audi R15 (2009):


Audi R18 (2012):

[chernaudi]

Still doesn't answer the question of if the R18 still runs torsion bar springs or coil-overs. The tight packaging supports torsion bars, but the HPD ARX-04 has a very cluttered front tub and it uses coil-overs.

And how would they change the springs, torsion bars or otherwise, anyways? I don't see any way they can access the much of the front suspension though the front of the tub.

Somewhat related on the production end of things, the next generation Audi A4/A5 series is rumored to introduce an actual e-quattro hybrid system inspired by the e-tron quattro racing hybrid system. It's expected to eventually supplement and partially replace the fully-mechanical quattro systems that Audi use in both longitudinal and transverse engine cars that are expected to use a part time or semi-permanent AWD system.

[mclarenf1papa]

Originally Posted by hcl123

-snip- 2014 Toyota engine only does 500 hp or so...

Current LMP1 engines are very likely producing upwards of 620 HP....the power figures quoted by the manufacturers are 99% of the time are wheel horsepower (which technically is more relevant).

For example, Audi says their engine makes 540 now, right? Assuming there's around a 13% power loss from the engine to the wheels, that means the total power output is around 620 HP.

[J Jay]

My turn to bump this.

I'm having trouble finding an exact quote or source for the hybrid troubles the #2 car had at Le Mans. Does anyone have a link to hand?

NB: I don't want this to become another "What if?" discussion between #2 & #7, been there, done that, got the t-shirt

[MulsanneMike]

Originally Posted by J Jay

My turn to bump this.

I'm having trouble finding an exact quote or source for the hybrid troubles the #2 car had at Le Mans. Does anyone have a link to hand?

NB: I don't want this to become another "What if?" discussion between #2 & #7, been there, done that, got the t-shirt

I emailed Ralf Juttner June 24, 2014 and asked:

Hello Ralf,

I'm hearing that the winning #2 Audi had its hybrid system fail late in
the race, from Sunday morning on. Any truth to this?


He replied:

Dear Mike,

Regarding the hybrid system on car #2: we had indeed an issue with the vacuum pump of the fly wheel towards the end of the race. For safety reasons we switched the system off completely.

[MulsanneMike]

Originally Posted by mclarenf1papa

Current LMP1 engines are very likely producing upwards of 620 HP....the power figures quoted by the manufacturers are 99% of the time are wheel horsepower (which technically is more relevant).

For example, Audi says their engine makes 540 now, right? Assuming there's around a 13% power loss from the engine to the wheels, that means the total power output is around 620 HP.

Something to consider, the mechanical-loss blanket number I tend to use is 10%, though recently an engineer suggested 5% might be more accurate. I might be revising my number to 7.5% in the future. I'd have to say 13% is very much on the high side.