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Thread: 98 350, spark advance?

  1. #1
    Junior Member
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    Default 98 350, spark advance?

    Just wondering how much main spark advance people are running on their 350's? before detination starts?

    Running 91/92 octane.

    thx

  2. #2
    Joe (Moderator) joecar's Avatar
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    Default

    What engine/vehicle/mods...?

  3. #3
    Junior Member
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    sometimes i don't think too far ahead...

    Truck is a 98 1/2 ton. 4L60E trans, vortec 350 engine, 3.73 diffs, 315/75R16 tires, approx 34.5" tall
    K&N FIPK, electric fans, true dual exhaust with aftermarket cats.

    I have a tune in it now but just wondering if i might be save with more advance. Complete table is +5 right now.

  4. #4
    Joe (Moderator) joecar's Avatar
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    What is your total timing at WOT above 4000 rpm...?

    Post your tune file... people love to look at tune files...

  5. #5
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    Default

    i attached the current tune.

    Thanks for any help!!!!
    Attached Files Attached Files

  6. #6
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    Did you tune it? It's got that factory curve to it. They go heavy on the advance in the midrange, but light up top. Up top you're less prone to detonation than down low or in the midrange where torque is peaking. You can usually add a degree or 2 after peak torque. It looks like you're pretty close where you're at, but the IMO the curve of it needs to be changed. I've zeroed out the PE timing adder table and suffer zero detonation at high kpa/low TPS/stoich fuel. My table's not perfect, and it's not done, in fact it's on hold for a PE light detonation issue, but it's a million times better than stock.
    1998 GMC Sierra K1500 5.7/4L80E, longtubes, 411 w/COS 5, marine cam/intake, Whipple. 91 octane at 6000'.
    1997 GMC Sierra K3500 7.4/4L80E, 411 w/COS 3, Whipple, small cam.
    2004 Corvette Z06 with longtubes.

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