(Solved) Mysteries of the Far West (Ride height varying for different tracks)

Discussion in 'General Discussion' started by Lgel, Feb 13, 2015.

  1. Lgel

    Lgel Registered

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    To avoid reading the thread :

    Ran the same tests with FISI (default setup) and changed the maths in Motec for smoothing ride height at 100.
    I found quite similar ride heights on the three tracks.
    So I recognise it's an error from my part due to a bad use of Motec.
    Thanks to all the posters and sorry for the loss of time.




    I am sorry to raise another question.

    As you know I am interested in setup work for cars, and for modern OW I rely heavily on Motec.

    I had the curiosity to compare ride heights of the same car (ASR 92 1.8) with the same setup and same fuel on board (lap 6 and 7) when mesured on two tracks ISI Portugal and ISI Sao Paolo, same air temp 29ÂșC.

    Car alone on track.

    In straight line at 280 km/h in Portugal you ride at front 3.2cm R rear 4.3 cm, in Sao Paolo (second flat straight) front 3.7 cm rear 5.3 cm (smothed by 50 measures to discard bump effect).

    Is it due to the disminishing air density, Sao Paolo being higher than Portugal?

    The differences seems very important.

    Can the more scientific minded of you confirm my findings?

    Once more don't kill the messenger, bring facts and an open mind.

    Thanks.

    P.S.

    Silverstone is between those two tracks front 3.6 cm, rear 4.8 cm.

    The difference in height between Silverstone and Estoril isn't very important if I am right.

    Now you may begin to understand why a setup for one track doesn't work so well on another.
     
    Last edited by a moderator: Feb 14, 2015
  2. Emery

    Emery Registered

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    Interesting. Nothing against the ASR '92 mod, but I'd rather see data for an ISI mod. Have you tested that?

    Also, are the points you check at level or do they slope? If they slope, do they slope in the same direction?
     
  3. TJones

    TJones Registered

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    IMO, one possible reason would be the very bumpy track of Estoril.
    I assume 3.2/4.3cm is the average rideheight of 50 measures. So on a very bumpy track like estoril, it's possible that some of those bumps compress the suspension and/or tyre's more than on the other tracks. As a result a few of those 50 values are very low, reducing the resulting average value.

    If the suspension are sitting on packers, maybe most of the measured distance (which isn't unusual), than there are still the tyres which get compressed by load.

    I would be surprised, if air density has any remarkable effekt on aero downforce.
     
  4. Jamie Shorting

    Jamie Shorting Registered

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    Hard to say what he means there. I thought he meant he added in a filter(smoothing) on motec to remove sharp bumps which basically means he's reduced the frequency of when the software records ride height. He might be better off looking at a histogram if that's the case. I don't think I understand his post though.
     
  5. Satangoss

    Satangoss Registered

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    You'd need to see the standard deviation at least. I don't believe the rF2 Physics engine goes that far to the point of include ar density in the ride height calc.
     
  6. Guimengo

    Guimengo Guest


    I'd follow this, take the car to Silverstone and Lime Rock Park and check on the main straights. Or Mores, though there isn't enough of a straight there. Always use "top" ISI content for your studies, then delve into third-party cars.
     
  7. Lgel

    Lgel Registered

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    All your comments are very interesting, but no one brings what I asked for, facts (take a car and check by yourself).

    My measures where given in straight level line, it's not due to the bumps, the whole ride height curves are totally different when you look at them ( I took 280 km/h as a reference point, but the ride height graph is different from beginning to end of straight).

    I took the ASR 92 car because I was intending to give useful feedback to the modder, and driving this car at the moment.

    I had already noticed strange things with ISI FISI and Marussia (same setup was giving to much difference in performance from track to track).

    For your info, in real life OW car's packers are tuned by 1/3 of a mm not 1 mm as in most mods for our game (that gives you an idea of the importance of ride height for OW).

    For Jamie, I use smoothing on certain graphs of Motec to average values (smoothing by 50, means it takes 50 measures and averages them if I am not wrong, it gives a better view of the global ride height eliminating high frequency variations).

    Thanks to all posters.
     
  8. Dalek

    Dalek Registered

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    Any chance tire flex could be in play ?

    An interesting value would be ride hight at different speeds too. Finding time this weekend could be complicated...
     
  9. Lgel

    Lgel Registered

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    Even if I didn't think that the car had anything to do in the problem, I did the same thing with ISI Marussia, at 280 km/h Portugal front 4cm, rear 5.0 cm, Sao Paolo front 5.0,cm, rear 5,8 mm, Silvertone 4,6 cm, 5,3 cm.

    You ride 1 cm higher in Sao Paolo, Silverstone being in the middle of both tracks, exactly as with the ASR 92.

    All tracks are current ISI tracks, I refuse to enter in the discussion wether I should only run at Silverstone or Lime Rock.

    There is no warning on ISI pages that on some of their tracks, cars will report wrong ride heights, or that observed ride heights should be adjusted from x mm on y track.

    Cheers and thanks for those who will try by themselves, and bring facts they have validated.

    P.S.

    For Marussia at both tracks (Silverstone and Sao Paolo) the Susp Force data is similar at 280 km/h.

    Made a test with ISI Brabham BT20 and default setup (very little aero, top ISI content for me) at the same tracks, at 225 km/h ride heights are similar.

    Mystery thickens...
     
    Last edited by a moderator: Feb 14, 2015
  10. Lazza

    Lazza Registered

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    I'm not sure how you're nailing down ride height figures with such apparent precision. I just ran down the most level straights I could find at Silverstone and Sao Paulo with plenty of ground clearance in the FISI2012 and the ride heights are all over the place, because of bumps and vertical G force variations (at least). Smoothing to 50 samples didn't help.

    If you could show some graphs you're getting these figures from it might help, but I personally can't see a way to reliably compare different tracks when I can't arrive at a single figure across 3 seconds on one straight.

    And Jamie, the smoothing doesn't discard the intervening samples (logging at lower frequencies would), but either way all I'm seeing is a mess. IMO the OP needs to provide a bit more evidence.
     
  11. Lgel

    Lgel Registered

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    Thanks Lazza, for your reply based on facts. When looking at the global ride height graphs the diference is clear, and I have found the difference consistent with three different cars (BT20 being the exception).

    I'll try once more with FISI and default setup which rides quite high.

    I am questionning what I am seing, that is why it is in the general discussion and not in the bug report section, as you, I know the difficulty of giving objective data.

    Cheers.

    P.S.

    Ran the same tests with FISI (default setup) and changed the maths for smoothing at 100.
    I found quite similar ride heights on the three tracks.
    So I recognise it's an error from my part due to a bad use of Motec.
    Thanks to all the posters.
     
    Last edited by a moderator: Feb 14, 2015

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