Suspension Theroies R-Us

Discussion in 'GT6 Tuning' started by IamWSPro, Jan 17, 2014.

  1. dtimefeel

    dtimefeel

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    I am not accusing you of not testing your car, but I am accusing you of not testing the dampers in isolation.
    If you tested the dampers in isolation like I did, then you can clearly tell me what will happen if you keep all your springs, lsd, etc the same (turn TCS off for this test), for each of the following profile on the first two corners of Nordschleife:

    Zonda R
    C 4/8 E 5/4
    C 4/7 E 6/4
    C 4/6 E 7/4
    C 4/5 E 8/4
    According to your theory, increasing the rear compression dampers will make it harder for weight to backward (reduce power oversteer) and decreasing the front extension dampers will also make it harder for weight to go backward.
    As you go down the list, if your theory is right, you should see worse (more intense) power oversteer on the first two corners of nordschleife.
    If your theory is wrong, you should see tamer (less intense) power oversteer as you go down the list.

    C 4/8 E 8/4
    C 4/7 E 7/4
    C 4/6 E 6/4
    C 4/5 E 5/4
    According to everyone else's theory, increasing the rear compression dampers will make it harder for weight to go backward (reduce power oversteer) and increasing the front extension dampers will also make it harder for weight to go backward.
    As you go down the list, if your theory is right, you should see worse (more intense) power oversteer on the first two corners of nordschleife.
    If our theory is wrong, you should see tamer (less intense) power oversteer as you go down the list.

    I have already done my testing and found that our theory is correct and your theory is wrong, at least for my current height/springs/ARB/LSD/TCS.
    Tell us your results, your arguing over the internet is fruitless since your English can't comprehend some of the things we're saying...
     
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  2. turismoslayer

    turismoslayer

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    Cripes! This is quite a discussion. I'll read rather than skim through it later. It should be linked in the FITT physics thread. Yeah?
     
  3. dtimefeel

    dtimefeel

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    I don't think FITT would be impressed by this conversation, it's just some french guy thinking the extension damper is actually an extension amplifier.
     
  4. turismoslayer

    turismoslayer

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    Ah. Dare I read it?
     
  5. Motor City Hami

    Motor City Hami

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    If the OP changes the name of this thread to something more relevant to suspension tuning I will link it in the FITT Physics discussion. If people are doing legitimate testing, it should be easily available to the community. I want to link to all relevant back and forth conversations, not just the ones that I agree with.
     
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  6. BlueShift

    BlueShift

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    Until you don't give sr/rh, nobody can properly test.
    Normal or inverted weigth under the car, balanced due to weigth distrib or not ?

    Tell me, because I cured some power oversteer/braking stab on my lfa with sr/rh/camber so we can compare.
     
    Last edited: Jan 20, 2014
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  7. Highlandor

    Highlandor

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    Please could you provide your car specs / test spec / regulations i.e. online or offline etc so others can re-create this?

    Thanks :tup:
     
  8. BlueShift

    BlueShift

    Messages:
    757
    Location:
    France
    ...
    ...
    ...
    No, you're speaking about front-rear weigth transfert, or drag-tuning. You think there's no left-rigth weigth transfert during cornering ?
    I'm talking about the whole.

    Jab on the brake = phase 1, after this it's phase 5, so yeah every damper work, I don't know why you say "you don't think like this, that's strange".
    Now you use your brakes mainly before cornering so you want the dampers to be corner-optimized unless you're doing a drag tune, a rally tune or anything unusual.

    Spring oscillation under strong braking / cornering / strong accel is not the main phenomenon, esp with strong SR. My cars never squat but on Le Mans / Nür straigths eventually.
    If you want to beleive this is the main thing, you're free, but that's not what I'm speaking about. I'd say get more SR while lowering RH and this is gone or so minimal that it won't bother you.

    In a rally car, what you describe is essential, but it's a niche car in GT6.

    Also

    Zonda is 43:57, I used
    - Ride Height : 73 / 74 -> almost flat
    - Spring Rate : 18.72 / 24.11 -> toward 43:57
    - Dampers (Comp.) : 5 / 10
    - Dampers (Ext.) : 3 / 5

    -> I guess from you ext balance test battery you propose that you have something like
    RH : 70/90
    SR 18/16 -> "inverted" from 43:57
    Then your damper collection.

    I also guess you have more front AR than rear, or a loose non-precise corner entry if you made the opposite.

    Raising the rear makes you wonder why you get power oversteer, really ? By raising it you've got understeer at corner entry and oversteer at corner exit.
     
    Last edited by a moderator: Jan 21, 2014
  9. dtimefeel

    dtimefeel

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    Location:
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    Yes, I asked you to use the same RH, SR, LSD, etc as usual.
    And just vary the dampers as I gave for four examples.
    Why can't you read English?


    Why are you putting words in my mouth?
    My tune is
    BALLAST: 110kg @ -33% (final weight dist 50:50)
    Downforce: 400/650

    Ride Height: 90/90 (completely flat)
    Spring Rate: 14.32/12.72 (in fact my SR is set up to fight against the braking oversteer)
    Anti-Roll Bars: 3/3
    Camber: 0.5/0.5
    Toe: -0.10/+0.25

    LSD:6/25/15
    And then Damper testing.
    Offline, SRF Off, TCS Off, ABS Off. (This is why I have my SR set up this way. If I had ABS on then I don't think braking oversteer would be present at all, so I could use my SR like blueshift to fight the power oversteer)

    What's with you and getting things backwards?
    Having a lower front (higher rear), just like having a softer front SR (stiffer rear SR) gives you better turn in (wilder braking oversteer) and milder exit (less power oversteer)

    However you can see that my tune is completely flat for RH, and compared to your tune, my RH and SR give slightly worse power oversteer. This is why my very first response to you said that your power-oversteer compensation comes from RH/SR and not from dampers.

    Because you think that in phase 1, only the front compression damper and rear extension booster (lol) are working. Right?
     
    Last edited: Jan 20, 2014
  10. Highlandor

    Highlandor

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    Offline & 110kgs ballast???? Car is pretty driveable online with 0kgs ballast with stock suspension and tuned diff...why so much ballast?
     
  11. dtimefeel

    dtimefeel

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    Location:
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    Because... I like 50:50?
    Also having more ballast = I can raise the power limiter more for 650PP
    Also I'm not a very talented driver (my time is only 6'40" with this tuning and so I don't think I'd be able to complete a lap with stock settings lolol)
     
  12. Highlandor

    Highlandor

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    I'm sorry, but I dont understand. Dampers aswell as springs and roll bars are important and powerful tools to help balance a car out, especially those that don't have a 50:50 weight distribution.. You want people to understand / believe what your saying about dampers but you're using an aid to artificially balance the car, instead of the dampers and the setup generally?

    Not sure what the power limiter has to do with it either, you could use a different setup sheet and run it without ballast?

    But I dont want to offend you, people use the game, drive and tune in different ways, if this is your way then it is not up to me to say this is right or wrong... each to your own, if this works for you, then go with it :tup:
     
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  13. BlueShift

    BlueShift

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    Here's 95% of your power oversteer... That car need no more than 9 there, I used 6 and it's allready the limit.
    Try something near 6/5/15, (I used 9/6/12 I think) and check if 95% of your problems don't come from this...

    The dampers control never more than 30%-40% of your power oversteer, somehow, it's more related to the control you have in this situation. Going in power oversteer is more a problem of loosing rear grip than road bumping. Your rear SR is the key.
    Anyway, there, your accel will make you primarily in this situation. Fix this before, then you can talk honestly about power oversteer by dampers.

    I guessed rigth about SR, you run with front stiffer than rear. This makes you have a flaw in rear grip. Your power oversteer also comes from this.
    You used balast, your choice, but without it you would have raised the rear to compensate an allready weak SR rear.

    If you keep 50:50, flat AR balance is a good choice and way to go. If you are at 43:57 and have still power oversteer, front < rear is the way to go (like 4 / 6 or 2 / 3 if you understand what is made, 4 / 6 or 2 /3 is depending of your SR. You can try a medium 3 /5 also). You can try front < rear at 50:50, but it's not this good in apex so you'd have to compensate via increasing rear camber.

    The dampers don't make everything, you are really changing the car in a lot of ways. You changing the spring balance on a flat car + accel setting, don't search anywhere else, it's there.

    Run flat SR balance (that's your secondary problem) / Flat RH and try 5 in accel to try if not all your problems comes from this. I also don't understand : if you have braking understeer, why you run at 15 decel ? Kill it !

    edit - I said before the edit "I don't even want to talk to you now", then I talked and talked and talked... :/
     
    Last edited: Jan 20, 2014
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  14. BlueShift

    BlueShift

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    Location:
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    And by the way, yeah rigth. When looking at dampers alone.

    You have rear to front weigth transit since you're in a straigth line and we allready agreed that in this case, ext/comp PER train can't work at the same moment. No inside to outside weigth transit so other damper can work.

    When looking dampers only.
     
  15. BlueShift

    BlueShift

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    Location:
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    Just quoting you to say you're rigth about ext speeds. What I was seeing on suspecting of being ext speed is in fact faster weigth transfer from stronger ext coming on slow higher comp settings.
    The weigth transfers faster due to high ext but the ext works slower, it's what you want to demonstrate initially I think.

    So the real deal is :
    Low comp setting = low comp strength & fast comp = fast weigth transfer
    High comp setting = high comp strength & slow comp = slow weigth transfer

    Low ext setting = low ext strength & fast ext = slow weigth transfer
    High ext setting = high ext strength & slow ext = fast weigth transfer


    (source : scaff tuning guide)

    On the point of the quote, you miss something important about SR.
    The spring that support the most weigth under corner exit or "power oversteer" like you call it (even if there's no corner, it's corner exit effects) are the rear's. If you have lower rear spring than front, you'll have a car that have a flaw in the rear and a advantage on the front, balance-wise.

    During a corner, or any turning situation, your weigth shift from your rear to front to front outside to outside to rear outside to rear back again, I hope we are agree on this or else we won't go far.

    Having stiffer front SR will make a car resistant to the bolded word, and half resistant to the other half bolded words :
    from your rear to front to front outside to outside to rear outside to rear back again

    Having stiffer rear SR will make a car resistant to the bolded word, and half resistant to the other half bolded words :
    from your rear to front to front outside to outside to rear outside to rear back again

    I also hope we agree on that or else we won't go far.

    "Power oversteer" is there :
    from your rear to front to front outside to outside to rear outside to rear back again.

    Due to SR, you need lower front than rear if you want to figth this correctly.

    The Zonda car is not 43:57 by car ingeneering fanciness. It's made like that so you'll have stiffer rear SR.

    If people want to have stiffer front, it's possible by raising the rear RH, you will have like this a hybrid setup, trying to get both advantages but setting it rigth is trickier.
    Raising RH induce moments and oversteer like weak rear SR and can be counteracted via AR Bars.

    About the LSD, still, try 6/5/5.

    Now that's being said, you can see now there's problems on the posted setup that masks damper real effects on your power oversteer effect, that can't really demonstrate anything probant.
     
    Last edited: Jan 21, 2014
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  16. IamWSPro

    IamWSPro

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    Changed the Title from (So I think I know why I hate GT6) to cue people into the fact that the thread became a Suspension debate and School of thoughts. Cool direction that headed
     
  17. Motor City Hami

    Motor City Hami

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  18. donpost

    donpost

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    I'm going to do what I always do when I see an argument about the effect dampers have on handling and that's post this article by Neil Roberts (Neil Roberts is a CART/Champ Car Crew Chief)

    http://www.ozebiz.com.au/racetech/theory/shocktune1.html

    Figure out which one of you agrees with him and you'll know who's right :lol:
     
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  19. BlueShift

    BlueShift

    Messages:
    757
    Location:
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    I'm not speaking about his 3b.
    The problems between us is a RH/SR/Ballast problem.

    Due to SR/RH choosed, I think is my car oversteered in corner entry and oversteered in corner exit aswell, his car understeered in corner entry and still oversteers in corner exit.
    I also thinks other things but I can't really say.

    That's why we recommend different actions.
     
    Last edited: Jan 22, 2014
  20. Voodoovaj

    Voodoovaj

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    This is a head spinning read.

    Let me add this - You are all correct in different aspects. And it's a little common sense that brings this to light. There's a bit of a failing in having only 7 steps, because the sweet setting is often somewhere between two clicks. 15 or 30 clicks, like a real adjustment, would be better. That's why a philosophy on damping works in some cases and not in others.

    The inverse weight thing is a moot point with the 1.03 update. Every car I've tested works better when suspended by it's proper corner weight (of course, I'm going to promote the wizard for this calculation).

    What I see missing in this discussion is the big difference that you have to account for with car weight and spring strength. In other words, a heavy car with soft springs will need different damping approaches than a light car with hard springs...and THAT is where the limited settings we have falls apart. Quite often going from 4 to 5 goes from too little damping to too much damping.
     
  21. Motor City Hami

    Motor City Hami

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    This is a great article. Has anyone tested this real world theory in GT6?
     
  22. Highlandor

    Highlandor

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    Dampers have no weight values attached to them, only the springs, springs are multi dimensional, they can serve more than one purpose, many in fact. Doing a setup by weight is one dimensional and not really the best use of springs, or setups as a whole.

    Doesn't matter what numerical values the springs, dampers or roll bars have, what matters is the balance between them and how that affects the natural balance of the car, aswell as other integral variables..

    But after 1.03 most things have gone to pot, the default custom suspension settings are so suited to so many cars, full on setups are almost redundant in certain situations. A quick tweak of 1 or 2 variables can give you something as good as spending hours going round in circles..

    Would love to see whats going to happen when / if PD implement this 7 way damper testing thing...maybe they'll change the physics to make this more relevant / useful..
     
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  23. Voodoovaj

    Voodoovaj

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    No weight component yes, but to say weight doesn't have an effect is lunacy. Damping, reduces the movement of the spring. The forces generated causes that movement. Weight, tire type, spring rate, all of that plays a role. The thought process for damping a spring that is 10kgf/mm on a car that weighs 1700kg on CH tires is not the same as damping a 10kgf/mm spring on 600kg car with RS tires.

    More weight will naturally compress a spring more and resist extension more. Take a spring you have lying around the house and put various weighted objects on it.

    You are are correct that balance matters and that 1 or 2 clicks can arrive at a good set up. I believe that is because damping (in the game) is relative to the spring. It's not an absolute force as it would be on an actual shock absorber where you are adjusting the flow of fluid.
     
  24. Highlandor

    Highlandor

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    Weight (not ballast) doesn't have an effect....for me it's a placebo, a red herring in GT setups..

    Yep, I'm a loon (trust me, I ((well, my shrink)) can prove it too)...

    That's not just weight thought is it, that's weight AND tyres...with a huge difference in grip levels..
     
  25. Voodoovaj

    Voodoovaj

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    Interesting. Obtaining faster lap times by adjusting the springs to suit weight reduction (or gain) must be an illusion. I wonder why all the tuners do it.:odd:
     
  26. Jack Napier

    Jack Napier (Banned)

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    Its easy to get a bit mixed up, it dont matter.

    The value represents the strength of the effect. Dampening effect slows the speed of the shock rod going up (comp) or down (ext) the higher the value the stronger the dampening will be and therefore slower movement of the rod.

    Keep in mind tuning dampers is fine but not if you overlook the basics in setting them up. Hint stiffer springs need more dampening ;) you dont want to set comp higher then ext (bouncy bouncy) and after they are set correctly you can tweak to find gains.

    Look at the SR slider like it has only 1 to 10 clicks, when setting up the spring rate if it lands where a 7 would be, set your ext to 7 and your comp to 5. You can tweak from there buts its a more dialled in starting poibt then leaving the damps 3/3 after jacking up the stiffness of tge springs. We go with 5 on the comp side ( usually start 2 clicks under ext setting) instead of 6 or 7 to leave room for tuning and to avoid restricting the suspention movement too much.

    After you can cross tune the damps for performance on the principle when one side is under comp the other is under ext during braking and accelerating.
     
    Last edited: Jan 22, 2014
  27. Highlandor

    Highlandor

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    What laps times, for what cars, where, when - lets see the results then....

    EDIT: and all the test data too
     
  28. dtimefeel

    dtimefeel

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    From further analysis and testing - I would say that it is completely situational as to whether increasing/decreasing which damper goes where.
    Meaning that for one setup of height/springs/ARB (such as the one I used in my test case), increasing front extension dealt with the power oversteer, but for another setup (such as the ones provided by Voodoova's Wizard) decreasing the front extension dealt with it.
    The reasons for the difference here cannot be as straightforward as what we've discussed here.

    In both cases, increasing rear compression damping helped deal with the power oversteer.
    This second set of test cases is more in agreement with donpost's article, and indicates that BlueShift is therefore correct for those circumstances - but for the wrong reason.

    The article doesn't go into any detail about why decreasing the front extension dampers helps deal with power oversteer, and perhaps it's still a mystery to the world's current science.
    What I can say is that it can't possibly be because extension dampers = extension boosters.

    My current theory, which is probably wrong, based on this very limited test data is that for suspensions tuned for initial understeer, the damping theory changes.
    Specifically:
    For suspensions tuned for braking understeer, increasing rear extension dampers will enhance this braking understeer effect. Refer to GT6 tuning screen.
    For suspensions tuned for braking oversteer, increasing rear extension dampers will enhance this braking oversteer effect. Refer to article by Neil Roberts.

    The first set of test cases that are contrary to the article and BlueShift, with regards to which direction extension dampers should go, were on suspensions tuned for braking understeer. Since this is in line with a number of (Gran Turismo) tuning articles, we may believe that their suspensions are also tuned for braking understeer.

    The second set of test cases that agree with the article and BlueShift were on suspensions tuned for braking oversteer. (lower front ends with sloppier front springs)

    My next question, then, is for guides such as Motor City Tuning's guide - where does the "always have compression < extension" rule-of-thumb come from?
     
    Last edited: Jan 22, 2014
  29. Voodoovaj

    Voodoovaj

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    Because you want the spring to compress, but you don't want it to rebound the same way. Quite often, on the extension stroke, the suspension will over extend. When it does that, it starts compressing again..hence the bounce.

    which reminds me that I have a bug to fix
     
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  30. Motor City Hami

    Motor City Hami

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    For the record, I have not published a section on Dampers for GT6. In GT5, dampers were not very dynamic. I used dampers in three ways.

    GT5 dampers:
    1. Compression a few clicks lower than extension to slow the return of the springs to neutral. This helped to reduce corner exit understeer. It also encouraged a bit of entry turn in, but to a lesser degree.
    2. On some occasions, like 4wd and FF tunes, rear compression a few clicks higher than extension to induce a rapid transition of weight to the front under turn in.
    3. To extremely game the system in GT5, for fussy cars like American Muscle, I used really wide split front like 4 compression and 10 extension and even rear comp/ext. This seemed to drop the nose of the car quickly for turn in, then hold it more planted through exit. When I tried this on less problematic cars, it created a really nasty corner exit oversteer.

    GT6 dampers:
    I haven't found the magic yet. If I wander too far from stock settings, my lap times are getting slower. I am also finding that dampers are more track specific than in GT5 with the addition of Bathurst and Matterhorn. I am teaming up with a couple other members of FITT to do some testing with the same car. If that turns into any useful results, I am willing to share mine with the community.

    I am really curious to see if I can replicate the conditions mentioned in the posted article. That will be where I begin testing.