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Thread: ASPARK Values in Excess of 100%?

  1. #1
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    Default ASPARK Values in Excess of 100%?

    So back in June I reinstalled the now rebuilt supercharger on my dually because I suddenly had a trip from CO to MI and back on my schedule that involved pulling my 24' enclosed with a Monte Carlo on the way back and I didn't want to get stuck either wringing the motor out or doing 65 to stay in OD so I slammed the blower on and with nothing more than a basic COS3 flash (had done larger injectors a couple weeks prior) set about on my journey. It seemed like I heard some spark knock initially, but it quickly went away. My time in MI was insanely busy and I hate that I couldn't slice off the time to log some data even if I didn't apply it. So here it is September and I still haven't addressed my slow TCC lockup issue. I've been putting it off to avoid a spark high/low relearn. I logged GM.ASPARK tonight and the resultant values ranged above and below 100% which made no sense, so I searched on here for ASPARK and it sounds like it still doesn't make any sense. Aren't values of 100% indicative of the PCM running off of the high octane table? Should ASPARK be treated as a long term spark trim with knock retard being short term? I've watched as I logged KR driving down the road and after a while, the KR disappears. Is this ASPARK stepping in? I must also balance the timing that I pull from the main map against IATs as they're pretty damn high with an unintercooled twin screw. I'm wondering if I ought to repeat this process in the middle of winter to maximize the spark map, then repeat next summer to address IAT map? Here's my log.

    Dually Log 4.efi
    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.

  2. #2
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    Here's a screenshot of my Aspark values. I've plotted them against RPM and dyncylair just like the spark map is in the tune.

    Click image for larger version. 

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    Another question. Does the scalar reset itself every time you turn the key off? Or are those values stores as sort of long term trims? At the moment, I'm not trying to find out where spark is going, rather I want to ID where knock is occurring and deal with it appropriately be it in the spark map or the IAT table.
    Last edited by Supercharged111; September 2nd, 2019 at 08:00 AM.
    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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    I never log aspark... I just log for knock to see where it's knocking and then pull some timing where it needs pulling.

    I would have expected aspark to deliver values between 0% and 100%, but it's obviously not doing that. Can you post your current tune file and the log you did with aspark.

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    This is frustrating, work has had me really distracted the last few weeks. I remember reading the email notification for this post and immediately brain dumped it. So what you describe is exactly what I've been doing all this time (pulling timing where KR is observed), but my concern was that, if ASPARK is a long term spark trim, there may be some timing that I need to pull from an area that I won't see being pulled via KR because ASPARK has that timing pulled already? I've watched my 1500 hit a load cell in KS I can't get here in CO and it was pulling like 6 degrees of timing via KR. After a minute or so it wasn't pulling any, I ASSume ASPARK took over here? I just want to better understand the relationship between the 2, because I could very well be making some assumptions here that just aren't accurate.

    Could my 2 bar MAP sensor account for ASPARK values above 100%?
    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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    Quote Originally Posted by Supercharged111 View Post
    but my concern was that, if ASPARK is a long term spark trim, there may be some timing that I need to pull from an area that I won't see being pulled via KR because ASPARK has that timing pulled already?
    When tuning spark, you should make high and low octane spark tables the same... then aspark spark timing 'trims' won't do shit.

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    Quote Originally Posted by statesman View Post
    When tuning spark, you should make high and low octane spark tables the same... then aspark spark timing 'trims' won't do shit.
    And just the other day I was reading that KR will still function when you do this which I previously thought was not how it worked. Easy peasy I like it. I've always just left the low octane table stock. Is 10 degrees a rational amount of timing to pull from the high table to build the low? I tune for 91 octane, but need to be able to account for a bad day and cheap gas when the only station in BFE only carries just the cheap shit.
    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.

  7. #7
    Joe (Moderator) joecar's Avatar
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    KR is short term retard; adaptive spark (sliding from HO to LO) is longer term.


    Hmmm, it is quite odd that ASPARK goes above 100%.

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