Launch Control

Discussion in 'Car Modding' started by Kinsman, Jan 28, 2017.

  1. Kinsman

    Kinsman Registered

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    I'm struggling with launch control...

    I set the launch control revs to around 5,500 out of 7,000. It's a single-seater vehicle (F3) but we need launch control for competition purposes (to stop people from losing control or bogging down and causing chaos).

    For some reason when I release launch control, the revs drop to around 1,000rpm and my car crawls off the line. I'm working on the engine.in file but can't see any parameters there that can help.

    Any ideas as to how to configure the initial file to keep the revs up for a smooth launch?
     
  2. DaVeX

    DaVeX Registered

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    I still don't understand how It works...:oops:
     
  3. Lazza

    Lazza Registered

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    You need to play with the HDV controls settings. Your engine does set which level of traction control will be used for launch control, then the HDV controls stuff lets you adjust how TC works. Also in the engine file you can set the efficiency, if that is quite low it will bog down more.
     
  4. stonec

    stonec Member

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    Sounds like your first gear is configured too long. The rF1/rF2 LC system isn't as sophisticated as real-life control systems, all it does is to cut down engine power until there is basically no wheelspin. You can choose between three levels of LC strength in the engine.INI (LaunchEfficiency), that's basically the only setting that makes a big difference.
     
  5. Lazza

    Lazza Registered

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    From the skip barber HDV, [CONTROLS] section:

    TractionControlGrip=(1.4, 0.2) // average driven wheel grip multiplied by 1st number, then added to 2nd
    TractionControlLevel=(0.33, 1.0) // effect of grip on throttle for low TC and high TC

    The first line lets you adjust how Traction Control 'sees' the current situation. The second then sets how much effect that has on current throttle input.

    The engine file has these lines:

    LaunchEfficiency=0 // efficiency (0.0-1.0) of launch control, or 0.0 if N/A
    LaunchRPMLogic=(5030, 6370) // holds RPM in this range before launch (used for AI even if launch control is N/A!)
    LaunchVariables=0 // level of traction control used (0-3) and whether auto-upshifting is enabled (add 4); default=7

    You obviously know about the 2nd one, the last one lets you choose the level of TC to use, and the first is some sort of efficiency adjustment. I've found lowering the efficiency will start to have the engine bog down, all else being equal.

    I would start by checking that your TractionControlGrip line produces values above 1.0 as grip is initially lost, then you can try reducing the effect of current grip by reducing the applicable parameter in TractionControlLevel (but obviously make sure your LaunchVariables is set so that you are using TC for the launch). Logically if your drivers use - or are able to use - traction control, playing with those values might effect their competitiveness. I would probably aim to allow low TC only, and use the high TC (level 3) for launch control, so there's no overlap.
     
  6. Kinsman

    Kinsman Registered

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    Thanks for the responses,

    Should have clarified - I'm not new to this and am familiar with the launch efficiency, variables and rpmlogic, but any values I've tried putting in there doesn't do much...

    The only allowed driver aid will be auto-clutch.

    Stonec - from what you've said, it sounds like the car tries to wheelspin from pretty much the moment you press the throttle, considering it kills the revs down to idle-levels...

    I'll play around with some parameters in the HDV and see if that helps. Will report back.
     
  7. Kinsman

    Kinsman Registered

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    Ok - figured it out.

    For anyone who has the same issue or wondered about the same thing, here is how it basically works.

    In the ENGINE ini file there are three lines:
    LaunchEfficiency=
    LaunchVariables=
    LaunchRPMLogic=

    In short, LaunchEfficiency is pretty much the clutch, and the rate at which it is engaged. An efficiency of 1 is a 'dropped clutch', which immediately engages. If you set it lower, the clutch engages more slowly.

    LaunchVariables essentially allows you to set what sort of a launch system you want. The possible values are:
    0 - No traction control, simple drop-clutch launch system.
    1 - Low traction control allowed
    2 - Medium traction control allowed
    3 - High traction control allowed

    If you wanted to allow auto-upshifts, add 4 to whichever traction control option you choose (ie. medium traction control and auto-upshifts would be 2 + 4, so enter 6)

    LaunchRPMLogic is simply two values that the revs must stay between when launch control is engaged - make sure it's in the power band but not at the rev limit.

    In the car HDV file under [CONTROL] there are two lines:
    TractionControlGrip=
    TractionControlLevel=

    The first one is the 'aggressiveness' of the traction control system (how much wheelspin is allowed before TC engages). Forgive me but I can't specifically remember whether it's a higher value that allows for more wheelspin or a lower one... I believe (and only believe) that higher values mean the traction control system engages LATER, with lower values allowing the traction control to kick in earlier.

    The second value is the strength of the traction control. There are two values - the first is the strength on the LOW setting, the second is the strength of the HIGH setting.

    Essentially it's about balancing the numbers. If you have a car with low power at pretty much anything but peak revs, lower the efficiency to allow for smoother clutch engagement (0.79 in my case), make sure only low traction control is allowed on launch, and then balance the TractionControlGrip and TractionControlLevel figures.

    If you want a smooth launch without too much traction control interference, set the TC GRIP level to a lower number (0.5, for example, to allow it to kick in earlier) as well as setting the TC LEVEL to a low number (in my case, 0.07) - this essentially meant that the TC kicked in early to keep the car pointing straight and true on launch, but the low LEVEL meant it only had a slight effect.

    Hope this helps anyone who had the same issue as me!
     
    Last edited: Feb 8, 2017

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