[WEC] BoP. Brilliant or Pants.

[tomcug]

Originally Posted by Articus

I think something was missing just a bit. While a Porsche or Cadillac could have won the race, it does not mean their performance was equal to the others.
In the dry weather stretches, the Ferrari and the Toyota simply streaked away from the Porsche and the Cadillac, especially on the straights. The LMdh cars were helped a lot by the safety cars which bunched the field together and then they simply capitalized on the mistakes of the Ferrari and the Toyota.

With the BOP they got Toyotas were immediately the favorites to win on pace (despite BS PR talk). Ferraris were a bit of unknown due to -1.9% power adjustment but it turns out it's nothing for them and should be more like -4/5%. Maybe for next year the ACO learns.

[Aysedasi]

What was it? 9 cars on the same lap at the finish? What do we want the ACO to learn?

[tomcug]

9 cars on the lead lap was in big part due to lots of safety cars. I don't say the BOP needs any drastic changes but LMDh cars need a bit more than they got this year. Same for the 9X8 with wing.

[Adam43]

But even before we got to the first SC we had many more cars than is anywhere near normal on the lead lap. And we were a long way into the race.

It’s false to infer it is because of SC.

(If cars on lead lap is your measure, which it isn’t really)


Sent from Le Mans

[joeb]

Remember when Porsche won Qatar and Spa?

[Adam43]

But at Le Mans there were nowhere.

In any other era if you only had a Ferrari and Porsche and they finished how they did. Or they were where they were all through the entire race (but SC!) we’d say it was a good race.

And there were seven other manufacturers!


Sent from Le Mans

[Articus]

Originally Posted by joeb

Remember when Porsche won Qatar and Spa?

The BOP was (rightly or wrongly) different in those races.

[Articus]

Originally Posted by Adam43

But at Le Mans there were nowhere.

In any other era if you only had a Ferrari and Porsche and they finished how they did. Or they were where they were all through the entire race (but SC!) we’d say it was a good race.

And there were seven other manufacturers!


Sent from Le Mans

To me there is a slightly tendency in this thread to get a bit overly defensive about the subject of BOP, if one does not tow the party line that "everything was perfect" after every event.

It was by no means a bad or one-sided race and I'm not really criticizing anything here. However I am always interested in the small margins for improvement, and there can definitely be some improvement. The first hour of the race before the rain showed the true picture. The Porsche and the cadillac were defenseless on the straights while not being especially faster in the corners. It will be important for the ACO to nail the power gain system in future rounds like Interlagos, Fuji, COTA, and Bahrain which all feature long straights especially if the LMH cars continue to run at the same weight at the LMDh cars (Ferrari was equal to the Porsche and Toyota only 10kg more).

One only need to remember this rubbish posted the other day: https://sportscar365.com/lemans/wec/floury-if-porsche-loses-they-will-have-done-a-bad-job/ by the supposedly "helpless" Toyotas.

[tomcug]

Originally Posted by Articus

The first hour of the race before the rain showed the true picture. The Porsche and the cadillac were defenseless on the straights while not being especially faster in the corners.

Exactly. In general it seems that the front axle hybrid helps significatly with straight line performance, in part thanks to 200 kW instead of 0 pushing the car forward on gear switch and seems that "loophole" never got really closed, listening to Ferrari onboards. Also the application of power gain was very, very conservative as no one got more than 1.9% and Toyota even had a positive change (LMAO). In the end both Toyota and Ferrari sandbagged nicely during the test day and the ACO never fixed the BOP. Which kind of also shows their approach to how they treat the big boys vs small garagists (remember "Alpine" LMP1 getting BOP-axed after the hyperpole despite being already behind Toyotas?). Another thing is that the ACO doesn't really seem to care anymore about the fact that LMH cars carry less fuel due to more hybrid regen but their dry weight is pretty much equal to LMDh now. In the end not a terrible BOP, but not a good one either by any means. Two horse race.

Originally Posted by Articus

One only need to remember this rubbish posted the other day: https://sportscar365.com/lemans/wec/floury-if-porsche-loses-they-will-have-done-a-bad-job/ by the supposedly "helpless" Toyotas.

That was the ultimate bullshit. They should be ashamed of themselves for speaking such nonsense (but I doubt they are).

[Articus]

Originally Posted by tomcug

Exactly. In general it seems that the front axle hybrid helps significatly with straight line performance, in part thanks to 200 kW instead of 0 pushing the car forward on gear switch and seems that "loophole" never got really closed, listening to Ferrari onboards.Another thing is that the ACO doesn't really seem to care anymore about the fact that LMH cars carry less fuel due to more hybrid regen but their dry weight is pretty much equal to LMDh now.

These are both good points. There are even still other areas where the LMH cars eek out advantages ( it is a death by 1000 cuts)

• The front axle deployment out of the pit box (200kw) allows them to put a little bit more energy into the front tires for temperature on the outlap.
  
• The front axle deployment on the straights allows slightly less stress on the rear tire over a long run compared to LMDh. Putting energy into the front tires on the straights also helps to prevent them from cooling down too much on the long straights at Le Mans.
  
• The front MGU allows them to use a mechanical differential on the front axle. This differential (in addition to the rear differential) gives the drivers more options for fine tuning the stability of the car under braking and balance of the cars in corners. By comparison the LMDh cars are essentially open differential at the front. This is one of the reasons that LMDh cars are often locking up the inside front tires more compared to LMH. In practice, the front differential of the LMH car works like an anti-lock braking system under braking (ABS). It prevents differences in rotational speed between the inside and outside front tire. Having pseudo-ABS is a big deal. it helps with late braking and tire degradation in the long runs.

These are practical advantages that will never be corrected for if you are only balancing the cars via the windtunnel numbers.


For those reasons and your point about the fuel weight, it was very surprising to me that they decided to run the LMH cars at the same dry weight as the LMDh cars for Le Mans. It was almost like they gave up on the platform equivalence for 1 race.

[Matador]

Originally Posted by Articus

These are both good points. There are even still other areas where the LMH cars eek out advantages ( it is a death by 1000 cuts)

• The front axle deployment out of the pit box (200kw) allows them to put a little bit more energy into the front tires for temperature on the outlap.
• The front axle deployment on the straights allows slightly less stress on the rear tire over a long run compared to LMDh. Putting energy into the front tires on the straights also helps to prevent them from cooling down too much on the long straights at Le Mans.
• The front MGU allows them to use a mechanical differential on the front axle. This differential (in addition to the rear differential) gives the drivers more options for fine tuning the stability of the car under braking and balance of the cars in corners. By comparison the LMDh cars are essentially open differential at the front. This is one of the reasons that LMDh cars are often locking up the inside front tires more compared to LMH. In practice, the front differential of the LMH car works like an anti-lock braking system under braking (ABS). It prevents differences in rotational speed between the inside and outside front tire. Having pseudo-ABS is a big deal. it helps with late braking and tire degradation in the long runs.

These are practical advantages that will never be corrected for if you are only balancing the cars via the windtunnel numbers.


For those reasons and your point about the fuel weight, it was very surprising to me that they decided to run the LMH cars at the same dry weight as the LMDh cars for Le Mans. It was almost like they gave up on the platform equivalence for 1 race.

All fair points... I think the BoP was pretty decent though, barring the fact that the power gain did pretty much nothing to null Ferrari's straight line speed advantage.


That being said, I think they balance to try match laptimes. If they are going to be that granular, then might as well they change the formula to a single spec car.

[J Jay]

The BoP served its purpose, but I get the feeling the ACO won't have minded that LMH's natural advantages bore out in the race. It would not surprise me to find out that the LMDh teams have mentioned this privately.

The ACO have genuinely done well to avoid the horror show that was 2014 TUSC, and the open politicking that dominated the latter years of LMP1-H. But a decision needs to be made in how the finer points are going to be tackled, as we are already at the point where they matter on-track.

[PhilipR]

Also we had 5 LMHs on the pace and only 2 LMDHs challening (Porsche 6 and Caddy 2) and the Caddy was brought in contention by Safety Car. The other LMDhs made errors and did not feature at the front. The LMH look better to me because there were more of them at the front

[Steve McQ]

Front axle energy deployment is only from 250kph, and tires generate hit in corners when they are loaded, not in straight line. And there is only one 250kph corner at Le Mans : Indianapolis 1, leading to a big breaking area.
I suspect you overestimate the advantages of using a non permanent 4WD system, while the car still have to drag a front axle "deadweight" for more than 60% of the lap, including at moments when weight repartition is critical like braking, turning in and putting the power down.
LMDh weight repartition is far more conventional and efficient. Plus they might be able to use more ballast than they do in battery packed LMH.

[veeten]

Originally Posted by PhilipR

Also we had 5 LMHs on the pace and only 2 LMDHs challening (Porsche 6 and Caddy 2) and the Caddy was brought in contention by Safety Car. The other LMDhs made errors and did not feature at the front. The LMH look better to me because there were more of them at the front

Of course, one has to remember that Porsche and Cadillac are in their second year in production in WEC, whereas BMW, Alpine, and Lamborghini are just starting theirs. BMW may have time in IMSA, but that's not the same.

We can also say a similar thing for Peugeot and Isotta Fraschini, one a re-design and the other a new entry. Both weren't a factor in the finish, but finishing nonetheless.

[Articus]

Originally Posted by Steve McQ

Front axle energy deployment is only from 250kph, and tires generate hit in corners when they are loaded, not in straight line. And there is only one 250kph corner at Le Mans : Indianapolis 1, leading to a big breaking area.
I suspect you overestimate the advantages of using a non permanent 4WD system, while the car still have to drag a front axle "deadweight" for more than 60% of the lap, including at moments when weight repartition is critical like braking, turning in and putting the power down.
LMDh weight repartition is far more conventional and efficient. Plus they might be able to use more ballast than they do in battery packed LMH.

Front axle deployment is from 190km/h not 250 km/h. 250 is the power gain threshold. Easy mistake.

Also front axle can be deployed in the pitlane at any speed with the full 200 kW. You could see the Toyota spinning the front wheels in the pits. A small but useful amount of surface temperature generated before the outlap.

Finally, it's not "front axle deadweight" because when not being powered, it still gives the LMH cars a front differential that limits slip between the left and right front wheel. It is a device that makes the car more stable in both wet and dry conditions, and prevents the inside wheel from locking under hard braking into the chicanes. LMDh does not have this. It is inherently more tricky to drive, and more likely to lock up and damage tires. The LMH can trail brake deeper into the corner without locking the inside wheel when they start to turn in which means they can brake later.

Finally, considering the 200kW system of the LMH vs the 60kW system of the LMDh cars, the Ferrari and the Toyota carry less fuel so, in practice, the LMDH cars are heavier than LMH when fueled for the race stint if you don't give the LMH cars more "dry" weight. The Ferrari was the same weight as the Porsche on the BOP table, which means it was lighter with a full fuel load than the Porsche. Hardly a good starting point for the inferior technical package.

[Steve McQ]

Absolutely, my bad on the 190kph threshold. All those rules got me lost

To be absolutely clear : I think all your points are valid, I used to be vocal a few years back against the ACO when they were trying to balance hybrid 4WD vs 2WD LMP1 with fuel flow, docking time etc... focusing on top speed only and missing completely the main thing with AWD : exitting like a rocketship from corners. (It was exactly the same during the infamous diesel era : petrol engined car were able to match diesel cars in top speeds, so there was no problem except they were 10" a lap slower).

However, I feel we are a long way beyond those dark ages, and most of these have been taken into account to reduce and offset the impact of such an asset. Maybe it is not perfect, but before going mad I would like to see the famous Adam43 graphs to compare real long term performances of the cars.

Oh, and the Peugeot 9X8 is a AWD LMH and it was slow as hell

[Articus]

Originally Posted by Steve McQ

Absolutely, my bad on the 190kph threshold. All those rules got me lost

To be absolutely clear : I think all your points are valid, I used to be vocal a few years back against the ACO when they were trying to balance hybrid 4WD vs 2WD LMP1 with fuel flow, docking time etc... focusing on top speed only and missing completely the main thing with AWD : exitting like a rocketship from corners. (It was exactly the same during the infamous diesel era : petrol engined car were able to match diesel cars in top speeds, so there was no problem except they were 10" a lap slower).

However, I feel we are a long way beyond those dark ages, and most of these have been taken into account to reduce and offset the impact of such an asset. Maybe it is not perfect, but before going mad I would like to see the famous Adam43 graphs to compare real long term performances of the cars.

Oh, and the Peugeot 9X8 is a AWD LMH and it was slow as hell

I agree that they are doing a brilliant job compared to the past and this year's race was a success and a great show for all. It shows that even missing a small amount, we are still going to see great races every time. You need a lot more than outright pace to win Le Mans, nevertheless manufacturers don't want to feel like they need to rely on misfortune of others, safety cars, and weather to keep in the race.

Regarding the Peugeot, of course, the Peugeot is a frankenstein car that was decided by a marketing gimmick, so its not so representative of the best that can be achieved under LMH regulations. There can be good and bad LMH cars, as their can be good and bad LMDh cars. But good LMH vs good LMDh, the LMH will always win that fight unless there is a balancing system like we have now.

[wewantourdarbyback]

Interesting point to add is that the #6 car was the fastest through the speed trap in the race, I think it was 344km/h. But the other two 963s could only manage mid 330s. Showcases why the 5 and 4 were nowhere, but the bit that interests me the most is that the 6 did not look like it was the fastest. As has been pointed out the 963s all looked like they couldn't get close to the Ferraris even with a run. Perhaps shows a little that BOP through data alone will not always be able to perfectly see the whole picture.

[chernaudi]

#4 was the fastest though the speed trap, and that was probably with a tow. In-race graphics for most the LMH and GTP cars showed them hovering between 325-335 kmh, often 330 or less. And that was across multiple cars in both subsets when without a draft.


Both types of car were slower, both in laptime and top speed compared to last year (probably due to running more downforce, and hence drag, to cater for rain forecasts and lower track temps). For comparison (same basic track layout), the fastest race laps in LMP1 in 2007 were 3:27s done by the Audi R10 and Peugeot 908 LMP1s. and top speeds for both was 339 kmh that year. And weather conditions in '07 were generally similar to this year.

[Articus]

Originally Posted by wewantourdarbyback

Interesting point to add is that the #6 car was the fastest through the speed trap in the race, I think it was 344km/h. But the other two 963s could only manage mid 330s. Showcases why the 5 and 4 were nowhere, but the bit that interests me the most is that the 6 did not look like it was the fastest. As has been pointed out the 963s all looked like they couldn't get close to the Ferraris even with a run. Perhaps shows a little that BOP through data alone will not always be able to perfectly see the whole picture.

The #4 just got a huge tow somewhere. The timing data even supports that it was a bit of a fluke result. The Penske cars didn't have much of a setup difference. In the timing data, it also shows the next 4 best trap speeds of that car, and they are much lower 333-335km/h. The Penske cars top speed was only 333km/h in average conditions. It was far away from Toyota and Ferrari who were closer to 337-339km/h without the tow.

[TF110]

The bop seemed closer than it has, but it might be that teams actually showed their full pace since it's Le Mans. I don't know if they'll make changes but the rain/weather did mask what could have been. For certain there's cars that aren't there, Peugeot, Lamborghini and Isotta

[Sodemo]

I’d rather they just equalise all the weights. If we are trying to make all the cars equal, weight is an easy one to achieve. I’d actually rather there be less variables.

Or make all the LMH cars a touch heavier, so LMDh can be 1030kg and LMH cars are 1040kg.

[Articus]

Originally Posted by Sodemo

I’d rather they just equalise all the weights. If we are trying to make all the cars equal, weight is an easy one to achieve. I’d actually rather there be less variables.

Or make all the LMH cars a touch heavier, so LMDh can be 1030kg and LMH cars are 1040kg.

To me, the reason we require BOP to begin with is because the ACO gave a wide performance window that the cars could be homologated at. Too large in my opinion.

You have extreme low drag concepts like the Ferrari trying to be balanced with more "F1 style" downforce cars like the Toyota, and then LMDh cars which are defined by styling cues, more than performance.


If they just placed a minimum drag level and max downforce level, and told everyone to show up within 0.1% of these numbers across the aero map, and also permitted rear wheel hybrid only, it wouldn't require much if any BOP.

[Articus]

What's interesting to me is that even in a spec championship like Indycar or Formula 1, you can observe performance differences between cars of different teams.


So the fact that the ACO managed to make performance of a bunch of different cars as close together as they have right now is nothing short of a miracle. It is hard, very hard.