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Thread: 5.3 turbo start up tune

  1. #1
    Tuner in Training
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    5.3 turbo start up tune

    Hi guys,

    I'm new to boosted motors and I'm wondering if any experts can look at my start up/idle tune/log and provide some feedback. It's a 3 bar SD setup. T76 turbo, 224/224 cam with 110lsa, 4l60e (I will most likely do a 4l80 soon), 80# decapped injectors.

    I'm curious about kPa at idle and vacuum. i setup a boost/vacuum gauge and i'm seeing -9.30 for vacuum at idle. And it's lean, which I'll work on. I know I need to work on VE tuning and spark, but i'm just making sure I'm off to a decent start.

    Appreciate any comments or thoughts you have.
    Attached Files Attached Files

  2. #2
    Tuning Addict 5FDP's Avatar
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    What MAP are you using?

    Your map kpa on key on and when you shut it off is rather high at 105-106kpa. It should match where you live. Like 100kpa key on engine off would be at around sea level.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  3. #3
    Tuner in Training
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    It's an LS1 style 3 bar MAP from EFI source.

  4. #4
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    Any other insight on this? My truck runs perfectly, but my gauge is seeing about 11psi boost, but my MAP is seeing about 6 ish (140kpa)

    My idle is about 70kpa also with a Sloppy stage 2

    hard 1-2.hpl
    Last edited by adnoh400; 02-02-2020 at 07:05 AM.

  5. #5
    Senior Tuner Frost's Avatar
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    sounds like maybe a Chinese knockoff MAP sensor was used instead of a GM unit... or the scaling is wrong... or both.
    Steve Williams
    TunedbyFrost.com


  6. #6
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    I sorta had the same thoughts, but I bought this from EFI source, the truck 3 bar map.

  7. #7

  8. #8
    Senior Tuner Frost's Avatar
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    Yeah, it's exactly what I said it would be... a Chinese / non-GM unit. When a legit, GM, ZL1 MAP sensor is under $40, there's just no excuse for using junk like this. There's places to save a $ and places where you should never. Although de-capped injectors are being discussed in this thread, so it's likely my feedback will be lost lol.
    Steve Williams
    TunedbyFrost.com


  9. #9
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    Huh, I thought I was getting a tested and true unit because I didn't want to run into this shit. I thought EFI source was reputable.

  10. #10
    Tuner in Training
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    OK you got me for a sensor and harness adapter.

    These look correct?

    linear 312.50
    offset -11.25

    See if I can smash this thing on a truck manifold somehow.
    Thanks