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Thread: "new guy" help tuning 4.8L supercharger

  1. #1
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    Default "new guy" help tuning 4.8L supercharger

    I had it tuned by someone with stock injecters. I puchased efi live last month to learn to tune my truck. I changed injecters to svo 30lb. The charger is a vortec with fmu and booster fuel pump. Fuel pressure is 43.5 @ idle and wot is 65. How to go about changing injecter flow table. I had 19lb injecters that were flowing 24.8019 and i was told to change the flow table to 37.3269 and now it is running rich. Please help
    THANK YOU

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    Prob need to find all the info on those injectors and see what they really flow. 43.5# at idle seems some what low? mine is 55 at idle and 62 with the Vacuum hose removed.

    How many PSI are you runnin with the SC? I have 44# injectors that are maxed out at 5psi boost on a 6.0L.

  3. #3
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    Thanks for the help Sorry fuel flow was 53.5 idle and 63.5 at wot. I am running 9.5psi at max rpm. I found what was wrong with flow table i loaded pcm the wrong way but i fixed it. How do i find out about the injecters. I do know that flow 30lb at 43.5psi. The truck is running better but at wot it falls on it face. I have been told to drive it for a day so pcm will set the tables up right.Then go and scale the flow table down some.

    THANKS FOR YOUR HELP
    Last edited by 00 truck; July 28th, 2008 at 01:29 PM.

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    Quote Originally Posted by 00 truck View Post
    Thanks for the help Sorry fuel flow was 53.5 idle and 63.5 at wot. I am running 9.5psi at max rpm. I found what was wrong with flow table i loaded pcm the wrong way but i fixed it. How do i find out about the injecters. I do know that flow 30lb at 43.5psi. The truck is running better but at wot it falls on it face. I have been told to drive it for a day so pcm will set the tables up right.Then go and scale the flow table down some.

    THANKS FOR YOUR HELP


    Whats your highest IDC? and whats your AFR in boost?
    What fuel pump?
    It could be your running out of Injector or fuel pump or both?
    Do you have a Fuel Pressure gauge in the cab?

    haha, thats a few questions.. but it should give a better idea of what the issue is.

  5. #5
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    IDC was 110.476 @ 4962RPM. AFR is 11.67 at same rpm. fuel pump is inline pump from vortech it flows 42 gph and stock pump in tank. DO not have fuel gauge in cab i have a snapon gauge i can hook it up and use in cab. At 3204RPM and the TP38% AFR was 14.68 and when i went TP 100% AFR went to 11.94 @ 3381RPM.
    Last edited by 00 truck; July 29th, 2008 at 09:16 AM.

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    Quote Originally Posted by 00 truck View Post
    IDC was 110.476 @ 4962RPM. AFR is 11.67 at same rpm. fuel pump is inline pump from vortech it flows 42 gph and stock pump in tank. DO not have fuel gauge in cab i have a snapon gauge i can hook it up and use in cab. At 3204RPM and the TP38% AFR was 14.68 and when i went TP 100% AFR went to 11.94 @ 3381RPM.
    ok...
    If your injectors could, they would flow 10% more... you need to get some bigger ones and go from there... and if i were you i would richen it up to around 11.2 in boost. and a Walbro 255 in tank would prob be your best bet.

    im not the best at tuning but i try.. ive learned alot of stuff from these guys on here..

    Post up your log and tune.. maybe some smart person will chime in to help..

  7. #7
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    Thanks for the help

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