Oreca 07 - Wrong ride height

Discussion in 'General Discussion' started by Mullog, May 9, 2019.

  1. Mullog

    Mullog Registered

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    Hi guys.

    Been having this problem for a long while, I tried to find my way through this but just didn't do.

    When I'm on track, I can hear the floor of the car scratching the ground, which clearly indicates that it's bottoming out. Then I go to MoTeC, and the data show a ride height for all corners of the car at least 2cm above point 0. Is it just me or is it a bug ? Or another secret trick for secret physics ?

    Thanks for helping me out guys.
     
    Dmitri likes this.
  2. davehenrie

    davehenrie Registered

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    a way to test it without motec would be to raise the car up to some ridiculous ride height and then monitor your Vmax on a long straight. Then lower the car to your normal range and see if you can achieve the same Vmax. Finally lower below your ride ht to verify if it really is a scrapping sound you are hearing.
    In the good ol days of GTR2, we could visually determine this due to sparks spitting out from under the cars. rF2 doesn't have that feature.
     
  3. Mullog

    Mullog Registered

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    I have tried this already, and it definitely is bottoming out while not showing so on MoTeC datas.

    Could anyone else check this please so I make sure I'm not the only one ?
     
  4. newtonpg

    newtonpg Registered

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    Well, well, well, 3+ days, 195 views and only one answer.
    C'mon guys we all know that there are many here with solid knowledge to answer.
    And this encourage me (a non specialist) to write some.

    It is because RHs from telemetry are NOT actual RHs. They need some correction factor(s) to reflect actual RHs.

    RH must be corrected by CorrectedInnerSuspensionHeigth and TireDeflection to express ActualRH (someone correct me if I'm wrong)

    CISH = Static Loaded Radius - Wheel Center Height - Design Ride Height
    CISH is in *.hdv file
    Design Ride Height is nowhere but the physics spreadsheet (must calculate)
    Wheel Center height in the *.pm file
    Static Loaded Radius calculated from data in tire.tbc
    TireDeflection come from telemetry

    Witch means you will need to disassembly the car's .mas file but wait... the "new" one's are encrypted.... forget or learn (This is NOT a reccomendation). Or you can run mod in DevMode and unfortunately I dont know how to.

    So the only way I know to overcome this is using telemetry data in a trial and error approach.
    Assuming that springs are setup correctly, when car is bottoming out (by far) RH will overflow in Motec, assuming negative values like -3120 mm, the same when chassis hit kerbs. You will need in some circumstances to raise tire pressure or more possible raise the car by short steps, especially in modern cars with lots of aero. And dont forget rake setup. Just in case of severe bottoming you may need harder springs.

    Far from my rig now and I think I dont have that Oreca07.
    Is this correct? I ask the specialists.
     
  5. Dmitri

    Dmitri Registered

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    At the moment what I've learned. Based on Motec and speed measures, anything less then 20 mm is bottoming out.
     
  6. davehenrie

    davehenrie Registered

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    stiffer springs? packers? Kinda repeating Newtonpg, sorry about that. But if your rake angle is steep, you could be driving the front splitter onto the tarmac. I haven't found any rules yet for the Oreca, but I did see the Aston GT3 had a 50mm minimum ride height. Anyone know the LMP2 minimum?
     
    Last edited: May 19, 2019
  7. Dmitri

    Dmitri Registered

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    It doesn't matter what kind of springs you are running. If its going lower then 20mm its scraping. At the moment its almost imposible to run springs lower then 800 at LeMans for example. Because it's botoming out. And this car handles way better on softer springs especially on braking.
     
  8. davehenrie

    davehenrie Registered

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    I found the 2018 ACO LMP2 Le Mans regs, and they mention PLENTY about the height of body parts above the plane and how tall the car can be, but I haven't found the minimum ride height. I know back in the mid 2000's they really raised the ride height in an attempt to slow down the cars. (lola's ex 257, B-40, Courage C-65) probably because Audi was getting irritated at having to race so hard at the smaller circuits.... but anyhow...if anyone else can dig up the number, perhaps we can shine some light on this dragging.
     
  9. Nielsen

    Nielsen Registered

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    Im not using rF2 at the moment but I remember this RH vs MoteC data discussion from iRacing.
    The devs used the argument that you have to find out where the (virtual) sensors are positioned and then input a correction value into MoteC.
    Another way (in iRacing) was to check the replay with a camera view underneath the car - to see either tiny sparks or actually see the car bottoming out/touching the ground.
    Just an idea.:)
     
  10. Alex72

    Alex72 Registered

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    We can hear the bottom scrape? Didnt Think we had audio for that. Cool.
     
  11. Stefan_L_01

    Stefan_L_01 Registered

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    The dallara f312 f3 car makes noise if aero pushes it down on a straight, however it does not make noise if you corner though Im pretty sure that you hit ground also with your outer cooler edge
     
  12. davehenrie

    davehenrie Registered

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    Dimitri? Are you sure the car is one of the S397 Oreca's from the Endurance Pak? I just took a quick spin in one and 45mm was the minimum ride height. Perhaps you have selected 3rd party Oreca instead of the S397 version. I'll see if I can compare.
     
  13. Dmitri

    Dmitri Registered

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    Of course I'm. We are talking about data not aboutc car setup here. Turn on telemetry and look at the ride height. It shows 20 mm but at that point car alredy scraping the surface of the track.
     
  14. davidporeilly

    davidporeilly Registered

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    I had this experience last night doing some testing at Le mans.
    I did some commentating for VEC 24 hrs of Lemans and it got me motivated to test.
    Once I softened front springs and lowered ride height I noticed my lap time delta eroding as soon as I got over 250 kph and figured it must be bottoming out due to aero load.
    I didn't get the scraping sound*.
    In motec this car only reports ride height at the 4 corners**.
    So I added packers to the front corner springs, quite a lot in the end like 1.5 cm. (3rd spring packers only available at rear).
    The top speed got back to previous levels plus it was more stable under big braking loads.

    *Why am I not hearing scraping, is it not enough sound effects?
    **Does anyone know why this car doesn't report the "ride height" in Motec?

    Trivia: Seems that marbles are only visible with track set to Med or higher in graphics settings. I saved the RR at the 18 hour mark in the race and there are a lot of marbles.
     
  15. davidporeilly

    davidporeilly Registered

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    Try packers increase.
    As the aero loads increase and the springs are squashed they will be stopped by the packers.
     
  16. TheLichten

    TheLichten Registered

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    I think the Front and rear Ride height values in Motec are tied to if the car has an Aero sensor, and S397 sneakily (aka not in the patch notes) removed that sensor and the engine sensor in an update this year
     
  17. Dmitri

    Dmitri Registered

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    * turn off engine sound and you'll hear a lot of it.
    ** It reports just the wrong numbers.
     
  18. Dmitri

    Dmitri Registered

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    With 4.5 mm RH and 2.5 packers no good. So thats not an option. But even with that amount of packers it doest solve the issue.
     
  19. krusti

    krusti Registered

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    To who is not hearing the scraping sound, could you try the Norma LMP3? I've very little experience with the Oreca, but a bit more with the Norma, and i've spent many time tweking the ride heights and packers basing only on scraping sound. Norma @ Daytona RC is a good combo for that.
    If you don't hear the sound here, then i think is a matter of volumes.
     
  20. AMillward

    AMillward Registered

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    Yeah, I did some runs and jacked the ride height all the way up and gained about 5mph.
     

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