GT3 cars aero balance in draft

Discussion in 'Bug Reports' started by Risto Kappet, Nov 10, 2020.

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  1. Risto Kappet

    Risto Kappet Registered

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    The GT3 cars aero balance moves in the wrong direction when in dirty air. They lose too much rear downforce and not enough front downforce.
     
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  2. davehenrie

    davehenrie Registered

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    Interesting discovery, and you have some heavy hitting names supporting this. Can you post some telemetry logs and tag Christopher Elliott ?? It will be interesting to see where this topic goes.
     
  3. Sebastian Pfeiffer

    Sebastian Pfeiffer Registered

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    It's the same with GTE cars since the big physics update. One instantly notices this, when following another car somewhat closely. Drive directly behind another car entering the Schumacher S and you will have a hard time staying on track. It's already noticeable with 2 or 3 car lengths between the cars.

    Regarding competition its the same for everyone, but probably not very realistic as you lose more downforce on the front and therefore should get understeer instead of oversteer.
     
  4. Nico Barclay

    Nico Barclay Registered

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    i just had a league race in a 3rd version SPA with GTE and cars have to lift 1s from car infront into eaurouge cause its like runing without a rearwing in the wet
    same for gt3´s thou it was a meme when guy has a run into the hairpin gets to the bumper but then has to lift 1s distance just to go tru the corner half pedal. when real spa gets released is gun be a meme with all the crash compilations, good laser scan track but no good laser scan physics jijiji
     
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  5. Risto Kappet

    Risto Kappet Registered

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    S397 has a paid physics team and a volunteer beta test group who can do that.
    Plus since the downforce channels are encrypted for the public drivers for trivial reasons, then its much faster and effective for devs with access to all data to go through this.
    Unless there is some spaghetti involved, normally it takes 2-3 lines in the .HDV to change the behaviour, 2-3 dabs and 2-3 one lap validation runs would be enough to normalize the situation, 10 min per car max.
     
  6. Robin Pansar

    Robin Pansar Member

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    I had a hunch that the turbulent air balance was off, but I couldn't determine because of the lack of data and the already very sensitive pitch aero.

    As far as I know, the draftliftmult value on x aero part has the biggest impact (unless official cars run a new system), so changing it shouldn't be too difficult. Some values on the body aero that determines draft also seem to have some effect, but I haven't looked into that too much. Finding data from teams could be tough, but I'm confident that there are CFD studies that show at least some data on how the balance behave and by how much it changes depending on car length to car ahead that can be used as a good reference.

    I don't know if the devs have some tool to calculate the balance and overall Fz% loss. There are some calculations in the public physics sheet where you can tune a bit, but personally, I haven't used it much so can't say how effective it is, but I assume it shows a very good estimate.
    On-track testing can work too, but obviously less accurate since it's difficult to keep a consistent distance from the car ahead. However, plotting Cz, cx coefficients and aero balance over speed you can get a very broad view of how it works and do some quickfire checks to see the % change.

    It would be nice to have some confirmation from the devs on this matter if the balance shift in turbulent air is incorrect or not so everyone won't complain about it for an eternity.
     
    Last edited: Nov 12, 2020
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  7. Duif

    Duif Registered

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    It seems like i also spotted that issue.
    When running Indycar series, with Apex Indycar 2020 mod, there was the same issue. After 1 race, we reported that to Apex Modding Team, it was corrected, and everything was back to normal.

    Recently, after last updates, especially on uphill parts of tracks, in GT3, it's really tricky to drive close to car in front, there's no downforce at the back at all. That can be easily spotted on, for example, Bathurst.
     
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  8. Daniele Vidimari

    Daniele Vidimari Registered

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    This was the case also in the VEC race of the past saturday at Nurburgring in GTE. Cars loose rear downforce very easily in fast turns like Schumacher S, add the exaggerated thermal degradation of the tires and here we go, a horrible experience.

    Also many guys crashed in the GT Challenge race at VIR due to that.
     
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  9. Will Mazeo

    Will Mazeo Registered

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    a real life Lamborghini factory driver telling S397 over and over (to the point that he gave up) that the effect is exagerated should be more than enough to confirm this lol
     
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  10. lagg

    lagg Registered

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    It's interesting.
    Who was the driver?
    Where can we find what he said?
     
  11. Stevy

    Stevy Registered

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    Could be Dennis Lind. I know he was on Discord but don't know if he said that
     
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  12. Will Mazeo

    Will Mazeo Registered

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    Dennis Lind. He said it a few times on Discord. I think he was also part of a group that made some huge report to S397 about some rF2 stuff just to be disappointed later heh

    I'm glad S397 at least use this effect tho, sometimes it seems to be non existent in other sims, especially on open wheels (to promote "better racing"), they just need to get it right.
     
  13. Duif

    Duif Registered

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    Seriously, we don't even need to share any Motec logs.
    This is simple thing to correct, and no reply from S397 is still disappointing. That's the same situation as in my post about performance issues. We can discuss, but we will wait months until it will be corrected.
     
  14. Andregee

    Andregee Registered

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    I noticed the same issue at 24h P1 Nordschleife race. My teammate lost the car at the same place of the track just driving behind a car.
    I think you should report the problem on Discord, because here nobody will notice it.
     
  15. Duif

    Duif Registered

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    When you do it on discord, you have a reply like: "report it on forum" ;)
     
  16. Andregee

    Andregee Registered

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    Report it directly to Christopher E. at Discord.
     
  17. Christopher Elliott

    Christopher Elliott Administrator Staff Member

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    We are looking into this issue and will keep you posted, thanks for the reports.
     
  18. J7166

    J7166 Registered

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    I was in shock when I saw him say that. Just inexplicable. I don't know where the problem lies with the studio at the moment. But there are some issues finding their way into the game, and remaining too long, too often lately.
     
  19. lagg

    lagg Registered

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    More content = more often
     
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  20. Will Mazeo

    Will Mazeo Registered

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    More content is not an excuse if things seem to be wrong from the base. It's clear they are having issues with physics ever since S397 took over.
     

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