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Thread: Very jagged VE table, but runs well, suggestions?

  1. #1
    Potential Tuner
    Join Date
    Mar 2017
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    2

    Very jagged VE table, but runs well, suggestions?

    Please look at my tune/ provide basic guidance. Im a noob. 5.3L twin turbo Ultra4 buggy. 7lbs of boost. All stock motor with 2bar SD OS, no MAF. Decapped stock injectors flowed at ~80#/hr at 4 bar. I have been tuning based on Dan Maslic's book using a turbo car case study as a guide.

    1. The injector duty cycle goes very high at high RPM and max boost. I started with the stock VE table and changed injector values until i had lowest average AFR error below 100 kPa. This wound up about 69#/hr and was used. This could be lack of fuel supply, i will look into logging fuel pressure. My walbro 255lph should handle it?

    2. VE table is very jagged. I've done a few iterations of test drive and tune, logging AFR error and multiplying by percent (discarding extremes). Each batch of VE changes shows good AFR error on the next tune. Any ideas if I have something else affecting my tune? It is scary fast, and runs well for how ugly the VE table is. Just want to get VE nailed down before moving to spark.
    Thank you for any help

    log 3-31-17_2001 - T19 4th VE changes.hpl
    layout_wb11.Layout.xml
    SD_T19 3-31-17_1823.hpt

  2. #2
    Tuning Addict 5FDP's Avatar
    Join Date
    May 2012
    Location
    Rogers, MN
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    14,066
    If the injectors flowed at around 80lb/hr, having the tune set up for smaller injectors isn't right. That's why the duty cycle is going so high.

    Use the editor to your advantage, do multiply by half % and then use the smooth sections icon in the VE table to help smooth it out. It just looks so jagged because your numbers are so close, like between 48-60ish for the most part and one "large" swing somewhere in the middle will cause the spike.
    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.