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Thread: No option for changing injectors on97 sunfire

  1. #1
    Tuner in Training
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    Aug 2010
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    40

    No option for changing injectors on97 sunfire

    I built a 97 sunfire for circle track racing and now the injectors are too small.
    leaned right out at high RPM. and injector duty cycle is at 100% for along time at RPM.
    I made the top feed conversion from a 2000 Cavalier,
    I got some ford,Bosch injectors (0 280 158 003) 24lb/hr.
    Now how do I change the file for these injectors?
    The only option is Injector const.
    I have bannish's table to change other injectors, but our OS dosen't let us change any of these settings?

    I would like to have this in the car for tomorrow. Tomorrow is race day.
    Hate to blow up another motor by running it lean.
    What are my options?

  2. #2
    injector constant is all you have.

    you need to scale it based on how much bigger your new injectors are, from memeory you scale it down for larger injectors.

    eg. if your old injector was 20lb/hr and new is 24 and your InjCont is 0.2 you would do:

    InjConstNew = 20/24 * 0.2 = 0.16667

    please confirm the fuel before you go doing any WOT running, my memory could be bad! You might need to scale it the other way.
    I count sheep in hex...

  3. #3
    Tuner in Training
    Join Date
    Aug 2010
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    40

    thanks we are on the right track

    This motor originally had side feed injectors. the closest thing I can find is it says it's 17 pounds per hour. The new injectors are 23.8 pounds per hour bosch injectors. According to the help file an hp tuners you are correct number goes down as the injector size goes up. I will use your formula to calculate value and try it in the car tonight thanks for such a timely response have a great weekend I will let you know what I find out.
    I was really hoping there was more it just means I hope it runs like this thanks for the help

  4. #4
    Tuner in Training
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    Aug 2010
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    What should I be looking for now?

    What should i expect to have to change in the ve tables?
    When I first got it running with the big cam I had to lean it out quite a bit to get it to idle and richen it up later in the RPM.

    Should it be rich all the way across the board ?

    went from a 17 to a 23.8 lb/hr
    changed the constant from .25573 to .18267

  5. #5
    Tuner in Training
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    Aug 2010
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    Ok,going to the track now. Got it pretty close. poke and hope.Lol
    Changed the constant to .2016 and richend up the idle and its pretty close.
    Will log today and see what we come up with.

  6. #6
    Tuner in Training
    Join Date
    Aug 2010
    Posts
    40
    Got it to run ok made a shall change at the track.
    Copied AFR ERROR% to the corresponding tables paste special, multiply by%.
    Going to try it again tomorrow.
    Weird thing is it didn't want to idle down and kept revving and running lean at random. Almost idled.
    After pasting some cells were at 100. Should i offset the ve , and how much?
    Last edited by o2l8; 07-31-2012 at 04:32 PM. Reason: spelling.