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Thread: E38 VVE Setup Guide

  1. #121
    Joe (Moderator) joecar's Avatar
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    You mean link the scantool to the tunetool... there is a setting for this.

  2. #122
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    Quote Originally Posted by joecar View Post
    You mean link the scantool to the tunetool... there is a setting for this.
    swingtan's AvatarJoin Date
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    Well....

    You only have 22 min worth of log data there, so you are going to be cutting it close to the minimum amount of data needed. I prefer to run logs of over 30 min, preferable over 60min when using street based logging. On the dyno you can use a much shorter log as you can hit the required cells more often. However, you can still use this log even though you didn't log E38.AFRATIO.

    What I'd do is check the tune settings for PE mode, and then filter out PE mode in scantool. You can then assume that the commanded AFR will always be stoichiometric ( or what ever was commanded, but it'll be fixed ). So you can make a custom PID to display a fixed BEN Factor for the commanded AFR vs the WB reading.

    Then invert the filter and do the same for PE mode, as if you set up PE as in the tutorial, then it should be a fixed setting as well. If you get really tricky, you can make a custom PID to work with both cruise and PE mode in one hit.

    It's a bit of work though and would be a little tricky, but it could be done. Or just redo the log using the correct PID's. I was talking someone else today about this and mt suggestion was to log the drive to / from work for a couple of days and then use the log joining tool to combine them into a single log. Then after filtering the data, use the combined logs to apply the changes to the VVE. When getting log data, keep changing gear up and down to vary the RPM and load, this gives lots of good data.

    Simon.

    I may not have used the proper words before so I copied and pasted then Highlighted Swingtons words. Log Joining Tool to put logs together into one log. How To ???
    LBL866

  3. #123
    Joe (Moderator) joecar's Avatar
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    Oh, yes, there's a log joining tool somewhere, I don't remember where it is... if you have multiple logs, the joining tool joins them together... just try it, you'll see how it works.

  4. #124
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    Question about the commanded AFR's - I had to scale the injectors in my 2008 Avalanche e38 by roughly 20% (did it by multiplying IFR table by 0.8 and dividing the stoich table by 0.8). Now that the afr table is different does this affect the desired fuel ratios referenced in the tutorial? Ie. If my stoich ratio for gasoline is now referenced as 16 instead of 14.7 (don't have exact numbers in front of me, sorry) due to the scaling do I also need to account for that 20% difference when entering the commanded/desired afr?

  5. #125
    Joe (Moderator) joecar's Avatar
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    Use EQR units to view the AFR table (i.e. the PE table).

  6. #126
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    Thanks, that's what I kind of figured. BTW, I scaled B4001 "Injector Flow Base" by multiplying it by 0.799 and scaled B3671 "Stoichiometric AFR" by dividing by 0.799 - I hope that's the correct way to scale?
    What was throwing me off is when I was looking at commanded AFR PID it showed that it was commanding 15-16 AFR even under PE. I'll have to read up how to change the BEN calculations to use Lambda or EQR instead of AFR since my wideband shows normal AFR ranges which is throwing the whole correction factor out of whack because the wideband serial readout is not scaled...

  7. #127
    Joe (Moderator) joecar's Avatar
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    Yes, correct...

    ( stated generally: multiply or divide IFR or stoichAFR by inverse scale factors )

    i.e as you have it, set B4001 to (IFR * X) and set B3672 to (stoichAFR / X) where X is 0.799.

    Yes, please use EQR.

    ( I use EQR for commanded fuel, and Lambda for exhaust measurement... this allows me to avoid confusion when speaking )

    Post your calc_pids.txt here.

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