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Thread: Add more throttle on idle.

  1. #1

    Add more throttle on idle.

    What is controlling final throttle position on idle?
    Cranking table controls initial position.
    I understand that VT basically controls the timing.
    I understand MAF with VE interprets airflow and decides on injection pulse and airflow model.
    Messing with either messes with fuel at the same time.
    Throttle body scalar doesn't do anything as far as I can tell.
    Reserve doesn't do much either.
    External load - not sure what it does either.

    Let's say I want to add 10% to idle TPS - how would I go about it?

  2. #2
    Senior Tuner
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    Why would you want to change idle TP specifically? To get it to idle at a higher RPM? The ECM will try and pull/add timing to maintain RPM and then adjust throttle position. I don't think there is a direct control of throttle position at idle or anywhere else.

  3. #3
    Quote Originally Posted by gtstorey View Post
    Why would you want to change idle TP specifically? To get it to idle at a higher RPM? The ECM will try and pull/add timing to maintain RPM and then adjust throttle position. I don't think there is a direct control of throttle position at idle or anywhere else.
    Because sometimes I disagree with what it decided is the best throttle position on idle, some setups require low timing high airflow to idle properly, and I want to know how to get it there.

  4. #4
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    Virtual Torque and Airmass determine calculated torque which in turn the ECU uses to decide how much throttle vs spark to use at idle. You can influence it if you know what you're doing. But unless you have zero pedal torque near 0, you will fight other issues.
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  5. #5
    Quote Originally Posted by TriPinTaZ View Post
    Virtual Torque and Airmass determine calculated torque which in turn the ECU uses to decide how much throttle vs spark to use at idle. You can influence it if you know what you're doing. But unless you have zero pedal torque near 0, you will fight other issues.
    Influences which way?
    More VT = less timing.
    More VE = ?

  6. #6
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    Quote Originally Posted by MoBoost View Post
    Influences which way?
    More VT = less timing.
    More VE = ?
    It all depends. It's been discussed in multiple threads on this forum.
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  7. #7
    Tuning Addict edcmat-l1's Avatar
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    Are we playing a guessing game? No year/make/model, tune file, data log, vehicle mods, nothing.

    What do we get if we win???

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  8. #8
    Quote Originally Posted by edcmat-l1 View Post
    Are we playing a guessing game? No year/make/model, tune file, data log, vehicle mods, nothing.

    What do we get if we win???

    looks-good-to-me.jpg
    Stock 2014 5.3 silverado with clogged cats and failed lifter.

  9. #9
    Quote Originally Posted by TriPinTaZ View Post
    It all depends. It's been discussed in multiple threads on this forum.
    Depends how in relation to final throttle position of idle logic?

  10. #10
    Is this a taboo question?

  11. #11
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    Play with the map side of the torque model then use the airmass model to balance it back out. in particular you either add or take away in the higher load. Needs to be shaped right so as when airmass is increasing torque is staying the same between the two models. There's also cranking airflow - that determines you min air - needs to be about 2 g/s over actual. In all honesty though, if the torque model is right and idle timing is from 7 to 18 degrees then you shouldn't need extra airflow.
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  12. #12
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    Quote Originally Posted by MoBoost View Post
    ... some setups require low timing high airflow to idle properly, and I want to know how to get it there.
    Increase torque reserve
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