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Thread: KR for off-idle tip in....concerning?....fix?

  1. #1

    KR for off-idle tip in....concerning?....fix?

    Could use some impressions on this little issue. Should I be concerned about these knock spikes? In other logs, they appear equally short, but can be as high as 1.4* KR. They seem to correspond with off-idle tip-in, and with shifts as I watch the TPS move after shifts. Always in the 800-2500rpm range, with 0.3-0.6g/cyl areas. I presume this is related to a lean tip-in with transient fueling. Tune and log are attached.

    SD with MAF deleted, OL in these logs. CL doesnt seem to help.

    '14 L77, 6L80e, DoD delete, stock rec port heads
    BTR PDS stg 2 cam with 122+6 LSA
    dual 90mm DBW throttles
    6-71 PDS
    headers

    I have already de-sensitizes the knock sensors to match those of a '13 CTSV, and upped the transient Impact and Evap factors to well over stock. Adjusting the timing doesnt seem to help proportionately.....takes ~10* retarded timing to get the spikes to go away.

    Also seem to get them randomly at idle and cruise....those logs also attached. Those logs have STFT and LTFT functioning

    any input would be greatly appreciated.
    Attached Files Attached Files

  2. #2
    Tuning Addict 5FDP's Avatar
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    May 2012
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    Disable de-soot mode to help stop the lean tip in issue under a quick stab of the throttle.

    The tiny little knock events aren't even worth worrying about, you'll drive yourself up a wall trying to remove that.
    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
    unfortunately that didnt seem to help. I keep playing with different Transient Impact and Evap settings but nothing seems to be helping the lean situation. it causes a stumble coming out of a light as well. it is less prominent with light input and more with moderate acceleration.

  4. #4
    so dont worry about it then? even if it is persistent?