ORECA P2 Engine mixture

Hi guys, my team raced 24h of le mans for first time with oreca p2. we broken the engine after 18 hour of race.
We had right temperature of water and oil and we race with mixture 3 (race).
So, for 24h is too higt mixture? Or we make a critical number of downshift (over 9000rpm)?

Thanks for the answer

 

What was your water and oil temps?
I tried to find what the optimal temps are for the Oreca or Gibson engine but couldn't find anything definitive. I think it's likely around 110 or 115 degrees Celsius.

I ran in this race too and we had the water temp under 100 and the oil temp under 110 in our LMP2.

I only drove for about 2 hours and I used qualy mix the whole time. I was also using drsshiftbeeps to indicate to me to shift at 8550 RPM.

We were able to finish the race but we did reduce the radiator tape and started shifting earlier near the end of the race.

 

Oil temp was 106° and water 93° and radiator tape is on 25%
I think we broken engine for the rpm dowshift, becouse i see motec file and we shifter from 8400 and 9000 rpm. I think its too high

 

Yeah we were running more tape than that in the beginning.

It may be from shifting too quickly and getting too high RPMs on down shifts.

See this request
https://forum.studio-397.com/index.php?threads/shift-protection.67772/

 

Our team also suffered from the problem in the 24 Hours of Le Mans with the LMP2. Our engine died after 9 hours. We are sure that we did not have premature temperature wear because it never got close to 100ºC. Normally around 95. This with a radiator closed at 25%. These are data that we review in the race at various times, since Motec does not obtain that data from the car apparently because that information is limited. That is why we cannot provide graphs that prove it.

If we have information on the RPM in the race that I attach as an example. In them it is seen that on very few occasions the 9,000 RPM that is established in the car as maximum is exceeded. And it is observed that all of them are in reductions (dark blue color).

The car's data is encrypted and therefore unknown. The only information available is the RPM limit that appears in the Setup, which cannot be modified from the program itself, which we therefore understand is a valid value for motor life.

If Studio 397 has not changed the parameters that rFactor had for engine wear, there are several data that are important to know, which unfortunately are unknown as the cars are now encrypted. Although personally I think that at least these data, such as the optimal temperature of tires and brakes, should be provided without endangering the rights of the program developers. In real life, these data are known to everyone, because they are provided by the manufacturers themselves.

Regarding motor life, what data should we know? Obviously the first as soon as it has been established. But not least the random range of failure that is established, because the real life of the motor will move in the established range between the life +/- the established random range. So if you want to be sure that the engine will not die just from wear and tear, you should never exceed the established limit minus the random range.

Now we must know which are the RPM and temperature limits that are considered normal and therefore have a wear x1. Once these limits are exceeded, it is necessary to know the range in which the excesses move. I give an example of what it could be. If the normal RPM limit in the LMP2 were 9,000 RPM, and it is established that up to 9,122 the wear is increased to x2, we already have important information, and that is that the range of excesses is 122 RPM. And here comes the important thing, what happens above 9,122? Well, the program understands that in the next range, that is, between 9,122 and 9,244, wear is doubled again, that is, x4. And so on. That is, between 9,244 and 9,366 it will be x8. Then x16, then x 32, etc ...

Exactly the same happens with the temperature of the engine. Therefore it is necessary to know up to what temperature the motor wears x1. And the range of increment to establish the wear. As an example, if it is established that the maximum temperature is 125ºC, and that the wear is doubled for each degree, then at 126 the wear is x2, at 127 x4, at 128 x8, etc.

And two more very important notes. Obviously, those wear above normal occurs only during the moments when you are at those thresholds. And no less important, and is that if there is excess RPM and Temperature simultaneously, the wear in those moments multiplies.

So far the reflection of how we understand that the engine life wear worked in rFactor. It would not hurt for Studio 397 to clarify if the wear parameters are maintained or have been altered. And in any case I think that the RPM and Temperature data that are normal should be provided. Very important as we have seen in Endurance races, such as the 24 Hours of Le Mans.

What could have happened to us at Le Mans? And possibly other teams as well. It is clear that the motor life limit was sufficient as there are many teams that have finished the race. Therefore ... possibilities: It may be that although in the setup you establish that the maximum RPM is 9,000, the limit from which wear increases has been set lower. It could also have happened that the random limit for the race was too high. But I find it difficult for these data to clarify them, although it would be desirable. Just in case I dare to ask for them.

These graphs show real data from the Le Mans race.

In the first image it is clear that the engine dies at the exit of the second chicane of the straights when giving gas without having produced a wild reduction.



In these two graphs you can see the RPM accumulated during the two turns that I played. Where it is appreciated that only on a few occasions the limit of 9.00 RPM has been exceeded. And that being without acceleration they are always in reductions. In any case, it is seen that it happens in a very few moments. The second graph corresponds to the shift in which the engine stopped, precisely on the lap in which it was time to enter to refuel after the second sting of the shift. that's why it is shorter.

Our engine died after 9 and a half hours of racing. And we are sure that at no time was the engine overheated.

 

1. To the thread creator: The engine mixture per se has no influence on the engine wear. There is no increased wear by running a higher mixture. However, higher mixtures obviously,as the name says, increase the fuel flow which in turn does increase the engine temperature a bit, which will cause increased wear. It depends on your radiator if it makes a big difference or maybe even no difference at all.

2. To the post above: Some of the numbers mentioned are correct, but not all. The "RPM 1" value is set below the rev limiter in all cars. In some more, in some less. The Oreca indeed is on the aggressive side. It is not 9000 but quite some lower. Also the Lifetime variance value is not correct I believe and the explanation on how it works. It is applied 50% down and up from the Lifetime average.

3. All the failures seen in VEC yesterday are logically explainable by how high people go on RPMs on upshifts and, to a lesser extent, how aggressive they are on downshifts. It is no surprise, as the peak power of the car is exactly on the rev limit. But this is not something that happened for the first time yesterday, these failures are the "norm" for a long time when people are not careful, especially on tracks with long straights. Over the years, since server crashes and with that restarts with new cars are rarely seen anymore, many teams have done their homework to figure out all the values themselves and some have not. But I agree that a) the values are extremely aggressive and b) they should be communicated more openly so everyone can get them without any effort.

 

Thank you very much for the information provided. A pity that the organization does not advise that the maximum RPM that it establishes in the setup do not correspond to the limit RPM.

A pity that being this way they cannot be modified downwards in the program itself as it is done in other cars. Obviously this has ruined the race for some participants. For our part, lesson learned. Although we are still surprised because we have already raced this car in the 24 hours of Le Mans in previous years, and finished the race three times.

 

Engine wear doesn't care if you're on power or downshifting - it's just rpm and temperature.

There's also not a "normal wear" rate. You're always at, above, or below the wear threshold on the temperature and RPM (calculated separately) and often the threshold is below redline. Tracks that feature very long straights then require more care, since it's not a normal driving scenario (rpm is held higher for longer).

True, but it's not a hard limit either. It's possible to start a session below average minus variance, or above average plus variance. It's just less likely.

Are race sessions subject to less extreme lifetime variance? I never tested myself, but I suspect so. I'd still allow 2x variance "for safety".

 

I made that comment because in acceleration we always try to be below the threshold that we understand to be correct of 9,000 RPM. Threshold that was only exceeded in some decelerations. Obviously the excesses of RPM and temperature count in any situation, accelerating and decelerating. And seen what has been seen, it is clear that the normal RPM limit is less than 9,000 RPM that is set in the fixed setup of the car, possibly also much lower to exhaust the life of the engine in less than 10 hours. Unless the random failure was very large and the system had assigned us a very high decreasing value. In that, chance is the boss, and nothing can be done.

I really do not understand why information as important to racing as those values, as well as normal operation of wheels, brakes, etc. is hidden. They are the rules of the competition, which there is no choice but to abide by if you compete, but I do not share or find justification. Many of these values are not detectable with training and tests. In addition, when some of them cannot be obtained for analysis through Motec.

I take this opportunity to thank Lazza for the work that has been facilitating our work in these aspects for years. Thank you very much.

 

Well... this is a homologated detuned engine full of electronics setting the limits to make sure they can run for way more than 24h in a row. This kind of information is not exactly necessary, they just have to... you know... simulate racing and get physics right.

 

If the over-rev wear & tear is so dramatic, how did all those Virtual 24 drivers, many of whom have never experienced a sim, survive that event. There were very few drop-outs if I recall. What was different between the 24v cars and the current Oreca? And for that matter, it was stated several cars fell out of the VEC event due to engine failure... Well how many finished?

 

The Virtual Le Mans race had mechanical failures turned off.

 

In D2, only 5 LMP2s finished out of 17.

 

In D3 they finished 8 of 17. But I cannot assure that all of them were for the same problem.

In D1 they also finished 8 out of 17. But I cannot assure you that any of them suffered from this same problem.

Surely many would have finished if they had known the limits of the engine. I still think that it is absurd to hide them, and that simulating the game by running alone does not serve to obtain those values, in addition to the fact that the random coefficient that has been assigned to you at the time of departure is not known. Although at least you know if the game comes alone, I guess without forcing at any time. Come on, what the game does in the simulation looks like reality the same as ...

 

Our drivers where fully briefed leading up the race on what not to do with the Oreca. Which is why the D2 car finished, sadly a GT took care of the D3 entry.

 

Guys what are you talking about !? This car is not from 1967. It has electronics to prevent this kind of scenarios.
Explanation like Offerermars did in live stream that we should test this before the race is a joke. And it's the same tone of conversation as it was before between Students and community . In a nutshel - nobody give a fuck about you thoughts on this or any other topic regarding the game.

 

I put it worse, if that information has been provided to some drivers.

This kind of thing and information should be made clear to all participants. And either I am very clueless, or the forum does not contain any information about it. If this information has been provided and we have not attended to it, it increases our serious career error.

If it were possible to provide a link to the forum in which it was published, we would appreciate it. We will have to be more attentive in the future.

 

We tested it and found the answer. There was nothing to stop you doing the same. You should always test everything ahead of Le Mans and leave nothing to chance. Tyres, fuel, engine - the lot.

I'm not going to give you the exact answer, but this page lists all of the shift points for cars on iRacing. The Dallara P217 has the same engine in as the Oreca: https://github.com/samkatakouzinosracing/nspace.hu-soundshift/blob/master/vehicles.ini

If S397 and iRacing both modelled the engine the same way then that shift point seems about right. Perhaps a little low, but better safe than sorry.

 

Thank you.

We had also done tests and we had not had problems with engine failures, or temperature. That if our training fuerode no more than 4 hours straight. And so far with the engine configuration that we had, we had finished the 24 Hours of Le Mans twice in previous years without suffering the problem that we suffered.

But as you say, in a 24-hour race, all caution is little. And we have learned the lesson. As we learned 4 years ago to solve the problem of the neutral that caused us a reduction of 300 km / h to reverse gear and also ruined our 24 hours. That won't happen to us again, and I'm confident that what happened to us this year won't either.

Thanks for the comparative data links you provide. although for the sake of the competition I still think that it would be better if these motor life data were known to the participants. It makes me sad that in such an important race there is so much abandonment for this reason.

 

That link that D Nichols has put I do not know where he gets that data from, but those 7900 RPM does not specify if it is the rpm limit or the recommended rpm to upshift (and I think this data is wrong) and I do not have Iracing but I found this: https://s100.iracing.com/wp-content/uploads/2020/12/UM-Dallara-P217-LMP2-v2020-12-9.pdf
The RPM limit is 8700, which does not match the 9000 RPM we have in RF2, and further down it says that the recommended rpm for upshifting is 8200 RPM.
I suppose more things would play a role in making an engine break down, but it would be nice if the game provided us with data on proper oil and brake operating temperatures.