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Thread: Testing Boost Control With Shop Air

  1. #11
    Join Date
    Nov 2013
    Chicago IL


    The things that can stop the boost timer.

    Transbrake Activation - only activates a temporary boost value.
    If you use dome pressure, it is in dome pressure values, if you use Dome+Map it will be in actual boost values.
    The Timer will Reset to 0 when you activate this switch and start the timer when you release the switch.

    TPS To Start Modulation Ramp - anytime you are under this value, your boost timer stops (but does not reset).
    Conversely, it is also a value that will adjust your boost value based on pedal position by a percentage.
    Example: Set TPS modulation to 50%. At 50% TPS you will get 0% of your commanded boost value,
    at 75% TPS you will get 50% of your boost value, and at 100% TPS you will get 100% of your boost value.
    To make it more clear, command boost of 10 psi.
    At 50% TPS, you get 0 psi boost, at 75% TPS you would get 5 psi boost, at 100% TPS you would get 10 psi boost.
    If you were to set the value to TPS of 75% to start the boost modulation, you would get 0 psi at 75% TPS, and Ramp to 10 psi at 100% TPS.

    Otherwise, ANY TIME your Boost enable Switch is active, the Boost Timer Starts in Boost vs Time & Boost Manual.
    the only difference with boost manual, is that it's designed for stick cars (hence the "Manual" transmission reference) which typically can not
    handle all of the boost in lower gears, so they often choose a lower boost in 1st gear, and on the rpm drop (showing the ECU a gear shift)
    it would move to stage 2 (or 2nd gear) and then to stage 3 (or 4rd gear), etc, etc.
    Don't forget to check out progress on my Race Car:
    Project Blasphemy - 8.07 @ 171
    Low 8 Second Street Car

  2. #12


    Quote Originally Posted by Five O View Post
    OK, the solenoids work fine and follow my boost curve perfectly. My question is this, I'm running Boost vs Time, Transbrake Launch check marked. It starts the timer as soon as I turn the ignition on. It restarts it when I hit the transbrake button like it should. If I use TPS Modulation, it won't start till I reach the point with the TPS. But it gives me full dome pressure once I hit my TPS value to start modulation. Seems like somethings not exactly right to me.
    Sorry, I hate to dig up an old thread, but this is exactly what's happening with my setup. Boost vs Time, want to trigger by transbrake, but it starts the timer when I turn the key on (without Master Enable selected). When I select Master Enable, it does NOT start the timer when I turn the key on, but it also does not start the timer when I push & release the transbrake. It has to be something really dumb I'm missing, but I'm stumped.

  3. #13


    Set as Boost vs Time (no Master Enable), mine also cycles the solenoids with key-on. I don't think that's really an issue, someone correct me if it is. Always end your Boost vs Time table with 0, so you don't drive around pits with boost commanded, and the controller trying to make it happen. Maybe someone else will chime in, but I think it's normal for the solenoids to be a little active. When you look at your dome pressure sensor with engine off and see it bouncing a tenth or two. The controller is trying to correct that. IMO

  4. #14
    Join Date
    Dec 2014
    Crossville TN


    Sorry, I don't remember what caused that, but I do remember it was something simple.

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