Simple Vehicle Setup Explanation

Discussion in 'Car Modding' started by taufikp, Feb 9, 2012.

  1. CdnRacer

    CdnRacer Banned

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    If you're TIGHT in you'll want to move weight to the rear. You're thinking in terms of static weight in which case setting up a car would be easy. Springs, shocks and weight distribution all effect dynamic weight.

    If race car setup was this easy there wouldn't be many large books written about the subject.
     
  2. jimcarrel

    jimcarrel Registered

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    Never meant to say that all you had to do with an oval track car was move weight more to the front for a quick simple setup.
    I mean, depending on the class of car, one might have 10 to 16 or so other settings (per tire) to play with for a good set up.

    As far as I know,in this type of car you will usually have more weight to the front (maybe 10%+ or so) and then use wedge to bias the weight to the front corner (towards the turn) and yes these two adjustments are tempered by all the other adjustments and yes it is a nightmare so to speak.

    As you know, one good setup for one will not necessarily work for another (because of driving habits, some like Loose, some like a little Tighter)

    Anyway, I'm not meaning to argue, just discussing. And by now I'm probably off topic.
     
  3. CdnRacer

    CdnRacer Banned

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    hahaha. No worries and no arguements here. :D I no expert that's foresure. :p

    I just don't want some modders to read this and think that the OP is 100% correct. Alot of it is over simplified. :D
     
  4. Rojas

    Rojas Registered

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    Thank you very much, Hazi.

    ... and, of course, many thanks to you, taufikp.
     
  5. theother5

    theother5 Registered

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    nice sharing folks .... tx
     
  6. joker68

    joker68 Registered

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    Thanks for this, guys. Much appreciated.
     
  7. Led566

    Led566 Registered

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    Just noticed an error in the differential lock part: actually increasing coast results in increased understeer off throttle.
     
  8. zim2323

    zim2323 Registered

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    I find the exact OPPOSITE to this...
    Front Positive: Improves turn-in STability, reduces turn-in ability (understeer)
    Front Negative: Decreases turn-in STability, increases turn-in ability (oversteer)
    Rear Positive: Decreases turn-in STability, increases turn-in ability (oversteer)
    Rear Negative: Improves turn-in STability, reduces turn-in ability (understeer)


    I look at it this way, if you are heading into a turn, let's say a right-hander, then when you enter, the car leans over onto the LF tire. If the LF tire is turned outward(positive) and that is the tire with the ideal grip/patch, then you're going to continue to go straight. If the tire is already turned inward(negative) toward the turn, then it's already heading in that direction, helping you turn in.

    Therefore, Front Positive=decreased turn-in, Front Negative=increased turn-in. With increased turn-in is less stability if the rest of the car setup is not balanced for the track/turn/turn-toe, while decreased turn-in means the car is more stable under breaking as it's not wanting to pitch into the turn quicker.

    And just thinking through, if rear is positive, pointing out, as you swing into the turn, the LR will become the dominate tire/patch and pull the rear of the car out, making it LESS stable, but more oversteer, while the opposite for each with negative rear toe.

    If this is not the case, can someone explain this to me?



    Also, don't forget that some mods have their toe reversed to where negative is positive and vice-versa, it's not always a slamdunk explanation.
     
    Last edited by a moderator: Sep 5, 2013
  9. kydiwl

    kydiwl Registered

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    You have to take into account how the change in camber (when turning) affects the change in toe. The outside wheel will actually lose toe-out when the camber goes more positive. Thus increasing the ability to turn. Don't think of any part of the steering geometry as being static.
     
  10. Doug Spinster

    Doug Spinster Registered

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    Sorry for bringing up an old thread, but Google brought me here.

    Question I have;

    DIFFERENTIAL LOCK > The description you give is this front wheel drive? I ask because when I try using the description you post and my Rear Wheel drive go squirmy around corners.
     
  11. mancslo

    mancslo Registered

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    What is the 1st steps to set GTE car with the rain weather?
     
  12. MotherDawg

    MotherDawg Registered

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    "Simple Vehicle Setup Explanation"... Let's get complicated...
    But then again, I'm not going to reinvent the wheel... of the diff for what matter?

    I'm about to offend a bunch of you, it's my fault, I just don't know how to write. Take the following with a smile.

    There's a few post in here that needs a few... pointer
    Doug Spinster: "my Rear Wheel drive go squirmy around corners"
    Micha080: "the car oversteers much more at corner exit"

    Lighting up the rears coming out of a corner all crossed up is for the kiddies... you know... the other crowd.
    As in, sorry but, you're doing it all wrong! ;)

    Augmenting the Power side of the diff does augment understeer as long as the traction is not broken. Over rotating the inside or worst, breaking both wheels loose... you can adjust the the thing to oblivion, when the energy is going up in smoke/heat, it's all useless.
    So as long as your tracking out, the quantity of lock will dictate how much the car actually turns... rotates.

    With a welded diff, 100% lock (a spool), the inside wheel turns at the same speed as the outside, the car does not want to change direction like going around a bend. It will promote understeer. Both of the wheels are forcing the front end to go straight, not turn.

    An open diff, 0% lock, both wheel can turn freely. One wheel can turn forward and the other backward and rotate around the diff itself. It won't impede any direction change.

    An open diff does not accelerate well as one wheel can break it's traction and start spinning all by itself. Putting some lock on the power side will reduce that. Now how much do you want/need to put in... go get a lunch, pull up a chair, I should be able to cram 30 years of knowledge in to 3 days... joke apart, it depends as much on the car as on the driver. Test, test and test again... without changing anything else in the car. In a car you know well (an over powered one like an end of the 60s F1), on a track you know well (not a long one so you can do 10 laps test runs inside 15 min), after a few run to get reacquainted, do one diff adjustment... not two... One. And nothing else either. Start testing. Come back to the setting you had before... then again to the same adjustment... what do the lap time say? And so on.

    On the Coast side, when lifting for a fast kink, a low lock setting will let the car rotate easily... sometime excessively. To high Coast lock will hinder your ability to make turn entry corrections. Lifting will not make the car turn around the apex. And so on.

    Here is two reference, as one needs to know how it really works and what are the actual parts/pieces the adjustments act on:
    A nice PDF by Taylor Race Engineering:
    https://www.taylor-race.com/sites/default/files/DIFFERENTIAL ESSAY W PHOTOS2.pdf
    And
    a 12 pages magazine article on (scroll to the bottom for the next page... passed the sponsors ads)
    "Everything You Need To Know About Limited Slip Differentials" by DSPORT Performance + Tech Magazine (I know... it's an article for the "other crowd")
    http://dsportmag.com/the-tech/speed...eed-to-know-about-limited-slip-differentials/

    Futher more, that are tonnes of resources on the web but most are quite bland. There is one that is a very good read. It came with Grand Prix Legend: "Four-Wheel Drift" by Steve Smith
    It explains things in a manner that easy to read and understand (small book with small pages). It was written when sim racing was in it's infancy, it does not uses any long words so it doesn't take a degree in mechanical engineering to understand. The first three chapters can be glanced over but chapter 4 "Tuning for Speed" can easily take some of the mystery out of a few things. The section on diffs is on page 53. Grand Prix Legend was a very difficult game and most people that bought it came away disgusted swearing that the game was "undrivable". The one that took the time to read the booklet and started with the lower class cars became men.
    http://sierrachest.com/gfx/games/GPLegends/box/Four-Wheel Drift.pdf
    One small thing to remember:
    In GPL, "power-side angle is HIGH" equals a LOW POWER percentage.
    In GPL, "number of clutches is LOW" somewhat equals a LOW number of PRELOAD.
     
    Last edited: Nov 18, 2018
    Gilles Benoit likes this.
  13. Richard Busch

    Richard Busch Member

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    Does anyone know of a place where I can download the original pdf? Complete with illustrations?

    TIA
     

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