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Thread: How to adjust VE with $OD

  1. #1
    Fuel Injected!
    Join Date
    Dec 2017

    How to adjust VE with $OD

    Can someone explain how to do it cell by cell as I donít use excel...

  2. #2
    Fuel Injected! steveo's Avatar
    Join Date
    Aug 2013
    with pretty much any table, you determine a correction that needs to be made, usually as a percentage, and where it needs to be made, then apply it with multiplication to the particular cell, and perhaps the surrounding cells as well.

    VE is calculated against current MAP and RPM, so you need the rough MAP and RPM where the change needs to be made at a particular point, and the calculated difference between your target (probably 128 trim) and the actual value. scroll through your logs to find good data points, the unfortunate thing is averaging data like this by hand is a pain in the ass.


    lets say you have a BLM trim value of 102 at around 50kpa map and 2000 rpm, while in closed loop, at a decent operating temperature, and want to adjust your VE table for that correction.

    trims are ideal at 128, so you can use division to find a multiplier that expresses the change that needs to be made: 102/128 = ~0.795

    then in tunerpro, you select the cells you feel are in that region (control-click for multiple cells) that are near 50kpa and 2000 rpm. in the function menu at the top, choose 'multiplication', and put 0.795 in the 'value', and click 'apply'.

    i would then view the graph (third icon from the left at the top) to see how that affected the curvature of the VE table, and perhaps smooth it a bit by hand

    this is tedious for sure and requires some instincts about how VE tables are supposed to be shaped, even if excel is used, you have to interpolate a bit.

    tunerpro has a feature called history tables that you can play with, that could do a rudimentary 'running average' as you play back log data. averages are way better than point-by-point log analysis for fuel trims. you have to be careful to clear it, then only play back sections of good data, such as not in power enrichment, in closed loop, not in decel fuel cutoff, etc.

    i also find this tedious

    i wrote this software called trimalyzer to make it easier to chew up logs and spit out VE corrections, it's free, it works best with tons of log data and you should still fine tune by hand afterwards. here's a how-to i wrote on how to use it

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