[WEC] BoP. Brilliant or Pants.

[Articus]

Originally Posted by chernaudi

Here's the relevant 4:1 downforce to drag rule stated in the ACO's 2021 regs:

"3.8.3 Criteria
The aerodynamic coefficients must fulfil the following criteria regardless of the car attitude (examples, but not limited to: front ride height, rear ride height, steer, roll and yaw):

1. Downforce criterion ClAmax = 5.20 m2
2. Efficiency criterion ?max = 4.00
3. Drag criterion CdAmin = 1.00 m"

Thank you for finding this.

Forgive me if I've misunderstood, but does it not refer to a "Max" efficiency criterion here? As in, it is an upper limit and not a class-wide 4:1 mandate?

[Articus]

Originally Posted by Adam43

What is acceptable here? What do we need this to be?

If you make the top speed the same, will you then make everything else the same? You’ll have to otherwise you’ve ruined the rest of the BoP.

Edit:

My point is that this could be too much messing.
We aren’t clear on the consequences of doing it either, or what should be achieved.

My thinking was actually to fix the problem at inception. Tighten the aero homologation window further so that teams can stop griping. That's a potential solution for the 2029 regs.

[chernaudi]

IMO, that's part of the problem to just BOP'ing to a laptime. Like the first couple of years of the IMSA Weathertech Championship. There was an almost absurd gap in terms of top speed between the DP cars and LMP2 cars, at least on the level of the Audi R10 vs the Porsche and Acura LMP2 cars in '07 and '08. Of course, both were like comparing chalk and cheese, and the ACO here at least have all the cars built to roughly the same technical regs (though LMH and GTP cars are still different).


You can't afford to have the cars having such a chalk and cheese performance discrepancy, but if you go down the parity route, you can't just change one parameter without looking at the others and tweaking them.


So what is the acceptable gaps between performance parameters while trying to keep the cars within a potential laptime window?


To be honest, I don't really want parity, at least on the NASCAR or old IROC levels. Then, you might as well be spec racing (which IROC was, after all), which I don't think anyone here really wants for the top prototype or GT classes.

[chernaudi]

Originally Posted by Articus

Thank you for finding this.

Forgive me if I've misunderstood, but does it not refer to a "Max" efficiency criterion here? As in, it is an upper limit and not a class-wide 4:1 mandate?

The source I found this from (a Reddit page, of all things) didn't expand on this. And this doesn't help due to this rule's parameters disappearing from public consumption, English language versions of the ACO's 2021 and later regs. Interestingly, the ACO do declare that the French language version is the definitive version for consulting what the regs actually mean as far as enforcement and interpretation.

[tomcug]

Originally Posted by Adam43

What is “decently”?

And how would they compensate the other aspects of performance? You’ve just increased the top speed of some (or decreased the others) - now you’ve got cars that are no longer overall in the same performance window.

Be careful of unintended consequences.

I know that, this was already discussed before and I said that increasing power for Caddys and Porsches would probably make them equal in race trim to Toyotas and Ferraris but faster in quali trim. Still, when your competitors blast past you on the straights after you had the slightest glitch in traffic or sometimes even when you're in clean air while you can't overtake them after catching 1+ sec per lap, this surely isn't decent enough. Makowiecki said it in the interview post-race, Ferraris and Toyotas had no issues overtaking them but the other way around was impossible even with pace advantage.

[Adam43]

Your post mainly arguing that in a straight line they had a pace advantage. No one is arguing that, although maybe it’s not as big as made out. But then we are on how big is big, that no one is considering.

It would make them faster overall. If they had more power and previously caught them 1+ lap at some points and now you give them more power. It would be even more in qualifying. If you are going to do that then you have to compensate elsewhere.

That they were in this situation doesn’t mean you have to change it!

Some cars are designed to be like this. Others are designed to be fast elsewhere. You are proposing to reward the ones that have a car faster in other aspects.

I bought a fancy meal and a bottle of water. You bought a sandwich and a bottle of Champagne. That’s not fair as I have no champagne. It’s OK the ACO is going to give me some. Enjoy your sandwich.

And we have people saying it is too much like a spec. series now and here we are trying to make it more so.

I’m sure that there will be tweaks here, but let’s be mindful of the complexities and also be careful what we wish for.

[broadrun96]

Dear god, the arguing over mathematical possibilities without any numerical data to support the visually based guesses is maddening. And then the everything must be exactly the same size, shape, lift, drag, etc. Ok, then watch LMP2 cause well that's what that was built to be

Oh and the Multimatic tub was used and had the joker updates as a Mazda and it won and was fast. If you're gonna denigrate a car at least have the facts to back up your claims.

[chernaudi]

It doesn't matter in the end, given that the Mazda/Riley/Multimatic DPI/LMP2 tub has nothing to do with the LMDH/GTP tub. Just look at the front suspension. The DPI car used coil over shocks and didn't even initially use Multimatic's shocks (an area where they excel in terms of design and engineering). The GTP cars use torsion bar springs at the front--a feature that was used front (and I believe also rear) on the Ford GT, of which the road and race versions were designed and built by Multimatic for Ford.



People complain that BOP makes things akin to spec racing. Sanctioning bodies try to shy away from that concept, and get criticized for not doing enough to ensure parity. You totally get rid of BOP, then we're back to LMP900 or LMP1 or early ALMS LMP2 where factory teams dominate and usually one or two of them steal the march entirely.


There's no winning with some people. Which is why sometimes I get burned out on stuff, especially issues in the real world that I hear people complain about but either do nothing about, or are basically out of their control.

[Articus]

Originally Posted by tomcug

I know that, this was already discussed before and I said that increasing power for Caddys and Porsches would probably make them equal in race trim to Toyotas and Ferraris but faster in quali trim. Still, when your competitors blast past you on the straights after you had the slightest glitch in traffic or sometimes even when you're in clean air while you can't overtake them after catching 1+ sec per lap, this surely isn't decent enough. Makowiecki said it in the interview post-race, Ferraris and Toyotas had no issues overtaking them but the other way around was impossible even with pace advantage.

Originally Posted by Adam43

Your post mainly arguing that in a straight line they had a pace advantage. No one is arguing that, although maybe it’s not as big as made out. But then we are on how big is big, that no one is considering.

It would make them faster overall. If they had more power and previously caught them 1+ lap at some points and now you give them more power. It would be even more in qualifying. If you are going to do that then you have to compensate elsewhere.

I’m sure that there will be tweaks here, but let’s be mindful of the complexities and also be careful what we wish for.

I think a solution (albeit not trialed by the ACO) is to increase the minimum weight of the LMDH which lack top end in order to reduce their cornering speeds, and then give them a power increase. In this way you don't actually make them faster, but you change how they make the laptime on the track. That can make them more raceable at Le Mans.

With that said, I don't know if it's better for the championship interest to homogenize everything (Chernaudi also noted this). Sometimes the racing is better because of the way the cars match up. It can be interesting to see a car with more corner speed try and overcome a car with more straight line speed and vice versa. This notably produced races like Silverstone a few years back with the Audi and Porsche trading places within the lap.

If one is simply an observer, the laptimes between the cars are very similar, but if you are one of the teams, you will inevitably gripe about top speed if you do not have it. Should the ACO react to this? It is possible to.

[Adam43]

Cornering speed, acceleration, tyre wear, energy useage, …
It’s not a simple puzzle.

And I am still not convinced you need to. Variety is nice.

What they could do is play a joker and move their car in the window? But then they wouldn’t like it so much at Laguna Seca.

On that this is potentially more of a talking point because the removal of a Le Mans specific aero kit.

[Articus]

Originally Posted by Adam43

Cornering speed, acceleration, tyre wear, energy useage, …
It’s not a simple puzzle.

And I am still not convinced you need to. Variety is nice.

What they could do is play a joker and move their car in the window? But then they wouldn’t like it so much at Laguna Seca.

On that this is potentially more of a talking point because the removal of a Le Mans specific aero kit.

I agree that it is not a simple puzzle, but the Toyota and the Ferrari manage to have great tire wear at higher minimum weights than the LMDH cars. This is interesting.


A Le Mans specific aero kit would be an interesting approach. That was actually something that was permitted in the latter stages of the LMP1 regulations (and in the LMP2 regulations around that same time!).

[TF110]

Bop doesn't account for the team's knowledge and experience. It also doesn't account for setup and tire usage/wear. You can have the best, most equal bop there is but if one team is better, you can't just beat them without actually being better with your car tgat given race.

[Articus]

I thought this was an interesting comment from Porsche NA President about BOP in the GT class:

"In the earliest of days, the car that won was only in the garage twice during a 24-hour race,” says Porsche Motorsport North America President and CEO Volker Holzmeyer. “Today, if your car breaks once, you're out of the race. I think it's getting more and more competitive. The drivers are getting better. Everybody has the perfect lineup. Therefore, I think every little tenth of a second matters much more, even in endurance racing.

"That's why I think BoP is getting more and more important. In the earlier days, there was no BoP, and it was fine! But it's all changed through the history and the competitiveness and professionalism.

"That's why I think we are now in a spot where two-tenths makes a huge difference. That's why we think, long-term... Yes, adding costs in general is just bad. There's no good thing about it. It makes this sport, which is already expensive, even more expensive.

"But if you spent that money and you have the feeling that you don't have a shot, that's not an option either.

"We want to keep the different car concepts. Rear-engined, front-engined, mid-engined. Turbocharged, naturally aspirated. Everyone's moving their engines towards the middle but there's still some boundaries and concepts, and therefore to keep this variety going, that seems to be the step we have to take.

"If everyone goes to a mid-engined turbocharged, then we end up with a spec series. That's not where the fans want to go or we want to go."

https://sportscar365.substack.com/p/...e-has-prepared

It's the realization that in the past, outright performance didn't matter as much because often times you just had to be consistent and reliable to win races. Now the competition is "too perfect", and cars run for 24 hours without fault so BOP anxiety is heightened. Everyone expects everyone else to run faultlessly because they have shown that they can! The quality of team, car, and driver is very high. It makes teams more anxious about the BOP because they don't think they can make a difference anywhere else due to the strength and depth of competition. When you are comparing Ferrari AF Corse to Toyota Gazoo Racing and Porsche Penske Motorsport, you are pitting perfectionist against perfectionist. It's a different game to the days when Audi could win Le Mans with the R8 while being handicapped against the privateers like Pescarolo.

[v8supes]

No idea about any of that tbh i just dont want one car being really fast on the straights or one car being really fast in the corners while both achieving the same laptime because as we see time and time again, the car that is fast on the straight is very hard to actually "race" against.

[helgi]

Are they going to "balance" top speed for Daytona and Le Mans? Or have I misread some articles in German?

[Articus]

Originally Posted by helgi

Are they going to "balance" top speed for Daytona and Le Mans? Or have I misread some articles in German?

Can you link those articles?

[Articus]

This is more of a GT BOP related topic, but SRO doesn't see need for torque sensors
https://sportscar365.com/sro/world-c...re-not-for-us/

Torque sensors are fine in prototypes, but I couldn't help but agree with his second point which was that for BOP in general, we want everything to be perfect, but not even one-make championships are getting things this close

IMSA, however, has appeared to hold its ground on implementing the sensors on GTD Pro and GTD cars next year.

“Will it prove to be a lot better than without it? We will see,” said Ratel. “For the moment, if you watched Spa this year, were torque sensors really needed?

“There were five [different] manufacturers in the top-six and nine cars on the lead lap in the last hour of the race.

“It’s close. You can always try to get closer but we’re getting to a point where… everyone wants everything to be within three-tenths of a second.

“Fine, but look at the Porsche Supercup. Look at LMP2, they are the same cars. Are these cars. Are these cars within three-tenths of a second? No.

“Driver’s ability, even if you have good Golds, Silvers, etc., teams, tire pressure, so many things. Two or three-tenths are everywhere.

“For now, everybody wants something that even one-make series are not able to deliver. We’re getting to a complete extreme.

[Adam43]

Whereas that Porsche article you quoted was about how Porsche wanted them in IMSA and liked them in WEC.

If you are top of the professional tree it is cool. It is a good thing. Expensive mind, so I can see how SRO doesn't want it. Fine too.

[Adam43]

Another thought, with Isotta Fraschini pulling out will the ACO take the opportunity to reduce the weights of all the cars?

There is 9kg room based on the lowest other weight in Sau Paulo (Cadillac and Lamborghini.

And if they do will Lamborghini still not get the benefit? How is their weight?

[TF110]

If Lamborghini gets weight breaks, will it matter? If they're overweight this year then the only thing helping them is more power. But that might not matter much at COTA. Maybe Fuji!

[helgi]

Originally Posted by Articus

Can you link those articles?

It was in one of recent "Motorsport Aktuell" magazines. If there's a web version I'll post it.

[tomcug]

https://sportscar365.com/lemans/wec/...-hit-for-cota/
Brand new BOP. Toyota looks quite nerfed, highest weight and very little power below 250 kph and let's be honest at tracks other than Le Mans it's base power that counts. Now the question is whether they still have some sandbags to remove after Sao Paulo...

[Steve McQ]

You are absolutely right regarding the power added over 250kph : I roughly calculated (in a very scientific way) that hypercars should be above 250 kph for 10 to 12 seconds per lap at COTA. Around 9% of the laptime probably.

[Adam43]

Better than nowt. So Toyota have barely changed in the >250kph stakes.

I can't do the >250 change for the others, but here is the latest on P<250kph, weight and P:W.

After a strong showing we see Toyota have been pegged back.

Cadillacs sandbagging hasn't worked for the home race. I am really getting the hang of interpreting the changes now and I feel I get cleverer every time I say sandbagging.

[tomcug]

Originally Posted by Adam43

Cadillacs sandbagging hasn't worked for the home race. I am really getting the hang of interpreting the changes now and I feel I get cleverer every time I say sandbagging.

Cadillac is close to minimum weight and maximum power allowed so clearly sandbagging works. Now only Chip's squad has to finally deliver.