Advice on Silvia for Indy Road

Discussion in 'Tuning General' started by no_affiliations, Sep 19, 2011.

  1. no_affiliations

    no_affiliations Licensed Racer

    using this car/ track as a starting point for training up for tuning and racing online; I've gotten to a tune that feels good to me and has improved my times and car stability significantly, but it still has some issues which are a little subtle for me..

    the main issues i'm having seem to me to be weight-transfer-related:

    overloading of the outside front tire through long corners

    overloading of front & rear outside tires if i try to balance through same corners
    with more throttle

    usually end up pushing both front tires through the chicane to the point where
    they overheat & smoke badly, but car still 'feels' ok; if i reduce steering input i go
    off track; at least part of this is bad line here, but i feel like it's showing me an
    understeer issue i don't notice elsewhere


    Height: -20/-18
    Springs: 15.0/13.5
    Dampers: 5/6
    Roll: 4/5
    Camber: 4.5/2.0
    toe: 0.0/-0.10

    LSD: 10/25/5

    Brakes: 4/3 no ABS

    thanks in advance for any help at all!
    Last edited: Sep 19, 2011
  2. RackAttack

    RackAttack Licensed Racer

    My guess is that this is doing way more damage than it's worth. I can understand the want to run without ABS, but really, there's no shame in it. You have absolutely no feedback in a sim racing game about whether your tires are locking up until it's too late. I'd say that this is leading to a majority of your front tire heat issues. You may not be lighting them up to the point where they're red, but it's still heating them up far more than they would with ABS on. That heat carries into the corners, and it only takes a smidge of understeer before you're lighting them up.

    That's a lot.

    Those are some really stiff springs, you might try bringing those down a bit. You'll find the car is more forgiving.

    I find this fairly interesting, are you trying to dial in some oversteer? Certainly negative rear toe is one way, but I think you'll find that if you loosen things up a bit, you'll get rid of some of that understeer.

    From your feedback, and based on your tune, I would recommend something like this:

    Height: -10/-15
    Springs: 9.0/9.0
    Dampers: 6/5
    Roll: 5/4
    Camber: 2.0/1.0
    toe: 0.00/0.00

    LSD: 10/25/5

    Brakes: 4/3 1 ABS

    If you give that a shot and you're not happy, tell me what it's doing and I'll make some adjustments ;-)
  3. clacksman

    clacksman Licensed Racer

    I can't help but notice you don't mention weight balance of the car. More on that in a second.

    Red front outside tire is too much steering input and/or speed. Can sometimes be mitigated with camber adjustment. Reduce speed and steering input until not red.

    Red outside tires is more of the same except the drive wheel reddening is caused by throttle input.

    Red fronts is too much speed and steering input again. Can usually be mitigated with reduced front brake and increased ABS, at some point along that line of adjustment it will cost you braking distance. Be going slower when turning in.

    Ballast: There's 200kg available to be added on any car. For races with a weight target instead of specified car build, make the car as light as possible (for a 1300kg target, as close to 1100kg as possible) and ballast it back up. The ballast can be moved forward and back and is a very effective handling and tire wear balance adjustment.
    Front tires give up/go red/basic understeer? Shove weight back
    Rear tires red/deadly oversteer? Shove weight forward

    Your tune (keep in mind I haven't used a Silvia much):
    Front height lower than rear adds a bit of understeer, might want to try reversing that split (-18/-20).
    Looks pretty stiff for springs; stiff springs generally help until the car is too easy to red the tires in curves at which point reduce spring a bit.
    Camber looks like way too much. I don't usually get any benefit to being over 1.5 and often leave it at my starting 0.9s.
    Dampers/roll/toe/LSD/brake within typical range of what I would do except I use ABS.
  4. no_affiliations

    no_affiliations Licensed Racer

    thanks, off to try it now; i had a feeling i had gone too extreme and needed a new perspective;

    as far as ABS; i'm trying to switch to it, but I keep rolling right past my turn-in; I wish the ABS allowed just a LITTLE BIT of lockup; i can see it putting too much heat in the tires as you said, so i'll work on re-training myself
  5. RackAttack

    RackAttack Licensed Racer

    It does if you push the pedal hard enough and turn a little.
  6. no_affiliations

    no_affiliations Licensed Racer

    weight 1300
    ballast 199

    completely forgot to look at this, could be critical

    thanks; off to try stuff out
  7. ttourist

    ttourist Licensed Racer

    My impressions:
    May need more spring split.
    Way too much camber.
    Brake bias is too heavy in the rear.
    ABS on 1 would be HUGE improvement once you get used to it.

    From your description of how the front tires are overheating in turns, sounds like too much camber, understeery car, tires already starting to overheat before corner due to no ABS, and just not slowing down enough for the car to handle it. More throttle is not the answer. Less throttle may be.
  8. ttourist

    ttourist Licensed Racer

    This. Will also lock in a straight line, though. ABS does not prevent lockup. What ABS does is allows the tire(s) to start turning again quickly after lockup. When ABS sees a wheel going much slower than other wheels, it releases that wheel's brake, returning braking control to the driver. If the wheel locks again, it repeats the process. This happens several times a second.
  9. RackAttack

    RackAttack Licensed Racer

    Have you tried using ABS at 1 with much higher brake numbers (like 10)?
  10. no_affiliations

    no_affiliations Licensed Racer

    Thanks, all: much improvement.

    to start, ABS = 1. Defeat admitted. Significant improvement, scary how late the braking is. Getting used to it. Additional Sentence Fragment.
    (bias 8/7)

    weight: played around w/ballast. simple 50/50 working well for me

    no LSD change


    Height -18, -18
    Springs: 12, 12
    Dampers: 7/7
    Roll: 4/5
    Camber: 1.5/0.9
    Toe: 0/ -0.05

    barely played with the height
    springs much lower = roll and dive
    dampers.. not much adjustment, maybe a little off.. this is one of those things i'm a little fuzzy on (not what the adjustment is doing technically, but the overall effect when combined with other settings)
    roll.. don't think i touched em
    camber... experts agree, so i turned it down. Experts are often (as in this case) right.
    toe.. adjusted out a little.

    I'm sure there's tweaking left to do, but i feel like it's in the ballpark now. As i ran it in the race, my hot laps were mid-low 147s at best and erratic; tune i posted this morning was down to upper 146s and a little better; currently down to low 146s and slower laps feel more like my execution is off and less like i'm wrestling with the car. I think most of the improvement i need to make now is my driving

    don't notice specific issues any more with overloading/heating that aren't obviously user error
    Last edited: Sep 19, 2011
  11. no_affiliations

    no_affiliations Licensed Racer

    oh yeah increase/hold/dump pressure many times a second. I've actually got some training as a tech, but putting stuff back to spec does not equal performance knowledge.. one of the things i've found frustrating is knowing WHAT i'm adjusting, but having trouble figuring out HOW to adjust it. Hope i don't sound punkish; i'm not trying to snap at you, I would much rather be told something i know than be assumed to know something i don't (learning = good). I suffer from the difference between book learning and experience. Greatly appreciate the sharing of knowledge and experience here at the TPRA.
  12. clacksman

    clacksman Licensed Racer

    Glad you're up to speed

    at least figuratively.
  13. no_affiliations

    no_affiliations Licensed Racer

    lol, thanks

    got a long way to go.

    i'm losing a painful amount of time in the chicane alone, but with the car right (or less wrong) i can see a lot of time to pick up with driving improvement
  14. SSRacing69

    SSRacing69 Administrator

    Keep in mind that driving line and technique are far more important than the tune. Fast drivers will be fast regardless of the tune because they can compensate for the cars deficiencies. Take 5 really fast drivers and compare tunes and you will probably find 5 different tunes.
  15. ttourist

    ttourist Licensed Racer

    Just a note about your comment on toe. You said you adjusted it "out." Going from-.10 to -.05 is actually making it less "out." Negative toe is toe out, positive toe is toe in. Positive makes front of the tires closer to each other. Not sure I read your comment correctly though.
  16. clacksman

    clacksman Licensed Racer

    I thought he was using 'out' to mean 'closer to zero' but good point.

    Not only that, but they generally won't like around half of those theoretical four other fast tunes.
  17. no_affiliations

    no_affiliations Licensed Racer

    just notices: 1:56 should be 1:46, at least i'm not that slow
  18. no_affiliations

    no_affiliations Licensed Racer

    I'm pretty sure toe-in is negative, and that it's labelled backwards in the game, so i'll stick to using the numbers
    Last edited: Sep 19, 2011
  19. clacksman

    clacksman Licensed Racer

    This confusion isn't new. Which symbol is attached to which direction of toe varies around the world. We're using what the game uses, see the little display in the tuning screen.
  20. ttourist

    ttourist Licensed Racer

    Yes, a lot of confusion surrounding this issue. Labeling is correct for U.S. Unless I've done hundreds of real life alignments incorrectly.

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