Difficult Car Spotlight - Oullim Motors Spirra

Discussion in 'GT6 Tuning' started by XS, Apr 1, 2014.

  1. DolHaus

    DolHaus

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    @Woodski_427

    (ds3, ABS 1, Grand Valley 10 laps)

    Low Speed Corner:
    Entry:
    Brakes are tricky at best but you've mentioned this already, if you can brake in a completely straight line then you're ok but any rotation will end in trouble. Initial turn in feels encouraging but then just turns to understeer, feels like the car can't rotate past a point.
    Mid: Stable but a lot of understeer, can't get the nose pointed in
    Exit: A small amount of throttle control required but not too bad, reasonably forgiving if treated gently.
    Comments: The car struggles with rotation, it feels like it can't turn in past a certain point before the front end just stops responding, makes it quite difficult to hold any speed.


    Mid Speed Corner:
    Entry:
    Understeer again, fairly stable if you stay away from the brakes though.
    Mid: Same rotation related problems, trying to fix it with a bit of throttle is to walk a thin line. You can get the nose to point in but the car gets upset awfully quickly and wants to snap round making it difficult to adjust.
    Exit: Can be a little bit unstable on the throttle but manageable once you're expecting it.
    Comments: Feels like I'm constantly fighting the car to keep it balanced, has a lot of understeer off the throttle and can snap into oversteer quite easily on it. Its not too bad, driveable but bleeds speed in the corners due to needing to nurse it constantly.


    High Speed Corner
    Entry:
    A bit of understeer but not too bad.
    Mid: Usual problems with holding a line but stable.
    Exit: No real problems.
    Comments: Didn't bring up any new problems, the understeer just made me lose entry speed in order to maintain as much speed on exit.

    Tune Comments: Overall it not a bad effort, its better than it started at least. It doesn't snap round in the corners like it did before but now faces the opposite problem, it can't rotate properly, feels like I'm running into an invisible wall constantly. I think its just a case of relying too much on one way of fixing the problem and ending up going to far. You've used the right ideas with raising the rear ride height and moving some ballast but they've left you with no real way of countering the negative effects of such actions. Maybe try removing the ballast and increasing your LSD Initial/Decel to counter the over rotation instead. Once you get it stable using the diff you can start playing with the rear ride height to add/remove rotation in conjunction with adjustments to the toe settings.
     
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  2. DolHaus

    DolHaus

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    Are you planning on using Rigidity Improvement? Just need to know before I put it on to test @oppositelock 's car (don't want to buy 2 cars lol)
     
  3. Woodski_427

    Woodski_427

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    @DolHaus - thanks for having a go in my car!

    I didn't remember it being that bad, so I went for a run round Suzuka. Yep, pretty undriveable and I struggled to keep it on tarmac :lol:. Then I changed to your tune on SH (it is on a tuning sheet of the same car) - did 2 laps, it felt pretty good and I was under 2:19.

    I looked at my set up and could immediately see the front was too soggy, so just firming that up improved the understeer. Then I got rid of the ride height difference and it improved again, then upped the initial and accel. a bit and I got under 2:19 after a few laps. Still some understeer under power and it's a bit twitchy but much more driveable.

    As you know, I don't proclaim to be a decent tuner and this car is perhaps not best for the novice. However, aside from my interest in the Spirra I did this as part of a learning process. As well as the more of understanding the technicalities of the tune itself (on which you were kind enough to offer some pointers), it is the tuning process I need to work on if start to do more tuning.

    I know I'm guilty of adapting to the car after a point when testing, rather than casting a critical eye and thinking about what is wrong then how to fix it. I also only drove this on Trial Mountain, which doesn't have much in the way of technical or low speed sections, and probably led to the softer setup because of the bumps. I know I used the brake release oversteer to get turn-in at TM and improved my times using driving rather tuning.

    This has been great in that I've had some criticism of my setup and I've been able to compare with yours and @Ridox2JZGTE tunes on the same car. Praiano's tune is something different and a bit specialised, and not a route I would normally go down. In fact I've come to the conclusion that ride height something to try after other methods haven't worked so well, or to use for a specialised tune.

    :cheers:
     
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  4. Ridox2JZGTE

    Ridox2JZGTE

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    The most important 1st step in tuning suspension is spring rate :) You need to find a good ratio that allows neutral balance of the car, the same process as in real life. There's no rule set for stiffer front or rear, some MR racing car uses softer rear spring with up to 1.5 ratio, 458 GT3 for example :) You need to take consideration of stock car behavior, it's weight distribution, driven wheel location and engine location. There is always a sweet spot of spring ratio for any given car, this will change when you reduce the car weight, adding ballast, changing the tires ( racing tire gives distinct behavior ), body rigidity usage and LSD setup.

    Drive some of my GT3 replicas, they all are road cars turned into race cars, with body rigidity and racing tires, and they can compete with GT3 cars on lower PP :D You can fine tune them, as they are base tune, good for learning too.
     
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  5. Jump_Ace

    Jump_Ace Staff Emeritus

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    I never use that rigidity thing in GT6 since there are no more severely used cars, they are all 'new' with 0 miles. I didn't really feel any difference in GT5 with it either.

    I saw that I completely missed that a Ratchet n Clank game came out last Nov. so I was busy yesterday :O

    Jerome
     
  6. DolHaus

    DolHaus

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    Ok fair enough, I'll wait until yours is done before finishing the testing.
     
  7. Jump_Ace

    Jump_Ace Staff Emeritus

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    Crap, I didn't know you were waiting for me. Sorry about that buddy, I'll make it priority 1 today when I get home.


    Jerome
     
  8. DolHaus

    DolHaus

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    No real rush, only have yours and 1 other left to test and its not like we're on a time scale here. Take your time, this car is tricky at best
     
  9. Jump_Ace

    Jump_Ace Staff Emeritus

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    Okay here ya go. This feels like a good compromise on turn in and full throttle on exit.

    Link.


    Jerome
     
    Last edited: Apr 25, 2014
    XS likes this.
  10. XS

    XS Premium

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    I doubt I'll have time for real testing and reviews before the month is up. Super busy at home and work right now. However, I really like what I've driven from everybody so far. Some still have that snap oversteer, just tuned down a little, but all are fast. This car can be a real competitor! It was always one of my favorite cars in the GT series, and now I have a reason to use it in GT6!
     
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  11. Jump_Ace

    Jump_Ace Staff Emeritus

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    I agree, it should be the car of the week next week. I dialed out some oversteer that would render turn in useless on 95% of cars and this thing just keeps spoiling the driver :tup:


    Jerome
     
    XS likes this.
  12. DolHaus

    DolHaus

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    3,865
    Location:
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    @Jump_Ace


    (ds3, ABS 1, Grand Valley 10 laps)

    Low Speed Corner:
    Entry:
    The brakes are extremely difficult to use, the back of the car swings around like a pendulum under hard braking making it a gamble every time you touch them. Turns in all right if you can get it stopped though.
    Mid: Neutral and stable with a hint of understeer if you try to push
    Exit: Smooth and stable
    Comments: The savage brakes combined with the super stiff rear make this car a handful on entry, I found myself having to be really early on the brakes so I could slow it gradually or gamble and brake normally hoping that I could counter the fishtailing and maintain some control. Once into the corner the car feels great, very neutral and predictable with no troubles on exit. The fully open lsd accel makes it a touch slow out of corners but you can get on the power without having to worry about it stepping out.


    Mid Speed Corner:
    Entry:
    The brakes were the main problem again, still wants to over rotate quite a bit but its not so bad as before. Did notice a bit of brake lift off rotation but it wasn't a major issue.
    Mid: Quite a bit of understeer present here when lifting off, the nose sort of turns in then straightens up unless you stay on the throttle. If you don't try to push too hard its fairly neutral, it just doesn't seem to want to go above a certain speed.
    Exit: Again smooth and stable, easy to get on the throttle and just power out.
    Comments: If you don't push too hard then the car feels pretty good, it just gets a little bit stubborn if you try and get more out of it.


    High Speed Corner
    Entry:
    Good turn in
    Mid: Stable
    Exit: Smooth and fast as long as you don't do anything to upset it.
    Comments: No real problems here, felt good but would get really twitchy if you ran a curb on exit or a camber/surface change. If you know what to expect then its easy enough to compensate for.

    Tune Comments: I have mixed feelings about this car, if driven casually and smoothly then it feels great apart from the brakes. Its easy to drive and smooth in the bends which inspires confidence, this is where the problem lies unfortunately. Once you start trying to get faster and work the car it becomes unpredictable and hard to use, sometimes it understeers, sometimes it oversteers, sometimes it feels stable, sometimes it just lets go with very little warning. It makes it really hard to use past a certain speed and feels like you can't risk pushing it because there's no telling what will happen next.
    I liked it but I can't really find a use for it, super easy to drive casually but not particularly fast, if you try and be fast with it then you are at the mercy of its mood. Feels like it wouldn't be fast enough to win at its own pace and is just too unpredictable at the limit.
    I'd suggest lowering the rear spring rates as they reach the limit of grip to fast and make it snap round instantly when you run a curb, too finely balanced with no margin for error which considering how the car feels when pushing makes it difficult. Perhaps raise your LSD decel and lower the rear brake balance to make the car better under braking. I think the stiff rear is making it too edgy, the tyres are way past their grip threshold as soon as load is applied and are just waiting to let go as soon as you do something it doesn't like. I noticed that the car feels a bit odd when you have to change direction quickly which would also suggest to me that the spring rates are too far apart, the front is grippy and progressive but the rear is super stiff so you can feel the weight transfer in action but have no chance of preventing slip.
     
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  13. DolHaus

    DolHaus

    Messages:
    3,865
    Location:
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    @oppositelock


    (ds3, ABS 1, Grand Valley 10 laps)

    Low Speed Corner:
    Entry:
    Hard to rotate during braking but extremely stable, fairly good turn in.
    Mid: A hint of understeer but not a problem
    Exit: Can be a little frisky on the throttle but manageable once you're expecting it
    Comments: Felt fairly good, the brakes took a bit of getting used to because it has a habbit of ploughing straight on under braking but once you adjust your lines its fine. Car feels a little bit heavy when you turn in but stays stable and safe.


    Mid Speed Corner:
    Entry:
    A little bit hesitant on turn in but stable enough
    Mid: Neutral/understeer balance to the car, can be controlled by constantly giving it little jabs of throttle to keep the nose turned in. Did notice that the car would get a bit unbalanced if you tried to brake mid turn, the front would stay planted but the rear would lose grip.
    Exit: Frisky again but manageable
    Comments:The car doesn't seem to have much rotation when off the throttle, you need to keep constantly poking at the throttle to keep it pointed where you want. Feels good once you're used to it but quite hard work.


    High Speed Corner
    Entry:
    Feels heavy and a bit unresponsive on turn in but reasonably stable
    Mid: Stable and planted
    Exit: Can catch you out at times, the rear wheels seem to want to spin up constantly even at high speed. If you get it right then it holds line and speed well but if you get it wrong it gives very little warning before letting go.
    Comments: Didn't feel entirely comfortable here but wasn't out of its depth either. As long as you use a little caution then its fine.

    Tune Comments: When I first drove it I didn't like it all that much, hard to stop, heavy on turn in, loads of understeer off the throttle and quite snatchy on the throttle. After a few laps of adapting to it and learning how it wants to be driven I started to enjoy it, you need to give it constant gentle throttle inputs to make it work and control the wheel spin on exit. It has to be driven with full focus to get the best from it, if you start trying to take it easy then it just stops behaving. This would make a great time trial car and would maybe be good for short races but would be too much of a handful for more than 4 laps due to the concentration required.
     
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  14. Jump_Ace

    Jump_Ace Staff Emeritus

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    Great write up DH, I'll try your suggestions :tup:


    Jerome
     
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