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Thread: Advice need for Timing adjustments. 94 5.7L TBI.

  1. #1
    Fuel Injected!
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    Advice need for Timing adjustments. 94 5.7L TBI.

    I have a 94 C1500 5.7L TBI with a 16197427 ECU RamJet Cam swap. I was wondering if anybody could help me out with some general advice for making timing changes to try to get the most out of my setup without breaking anything. I have a Autoprom and I am pretty familiar with tuning the VE tables in TunerPro RT, but I left the timing alone, other then adding 10 degrees of initial timing by rotating the Dist.

  2. #2
    Fuel Injected!
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    It is safer to add timing if you are richer, do you have knock sensors? I would be conservative and add a few degrees and see how it runs. See the below from Solomon

    For stock engines, when running 92+ octane fuel, you can begin by adding about 2° of spark advance across the two Main Spark Timing tables, to get more power/better efficiency out of your combustion. Monitor this increase with a scanner/logger and make sure you aren't getting any consistent knock retard. If you are, note in which RPM range it is, and at what MAP value, and take 1° or 2° out of the appropriate Main Spark Timing cell.

    You can pretty much add advance until you feel the engine holding back or skipping, or get spark retard, and then back it off some. This will generally produce the cleanest combustion and best throttle response. However, sometimes you can have too much timing without knock (power will fall off), so the best way to fine-tune timing is on the dyno.
    Last edited by Aroberson77; 07-20-2017 at 03:07 PM.

  3. #3
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    I do have a knock sensor

  4. #4
    Fuel Injected!
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    I am finally getting to the point of timing as well. I was under the impression that you keep adding advance until you get knock counts for a cell, then you bring it back a couple of degrees. Is this not a good practice?
    1994 Chevy G30 Van "Big Blue"
    5.7 TBI, Vortec Heads, Summit Intake, Thorley Short Headers with dual 2.5" exhaust, 4L80E transmission

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