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Thread: P12 VE Tuning

  1. #1
    Junior Member dennisscars's Avatar
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    Default P12 VE Tuning

    I'm trying my hand at VE tuning with the P12 and it's coming along but now I'm wondering since it's not logging g/cyl (east/west) only rpm on the timing table.

    How do you log timing so you know where to change timing along the g/cyl column(s)?

    We don't seem to have any *_DMA supported PID's and probably more importantly does it move east/west with no g/cyl readings from the MAF while running behind the curtain?

    So far I'm only running neutral rev's. Wondering if it's only reading from the left most column all the time.
    Thanks

  2. #2
    Joe (Moderator) joecar's Avatar
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    Hi denniscars,

    Do you have any pids whose units are g/cyl...? If not, then try CALC.CYLAIR (which computes g/cyl from MAF g/s and RPM).

    We can edit cal_link.txt to include CALC.CYLAIR as a link pid for the spark tables, if necessary.

  3. #3
    Junior Member dennisscars's Avatar
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    Joe thanks for the reply,
    Yes we have CALC.CYLAIR, which after finding out the hard way, needs to be converted to CALC.CYL4AIR (4 cylinder) and logs correctly, so long as MAF is reporting.

    I disabled MAF signal wire, as we cannot disable via software, leaving the IAT sensor. Which means that all spark values now log to the .08 column. Further research appears that that's where it is pulling timing, solely from the .08 (0.00).

    Which may not be a bad thing to have singular dimensional timing in my off road application so long as I know where it's pulling from. Stock timing at the .08 column is something crazy 43* because you shouldn't be there at 6,000 rpm with .08 g/cyl.

    I'm going to try, next chance, replacing .08 with something reasonable 20* and anything >.08 something unreasonable like 5* throughout to test my theory. If all I get is 20* then it's only reading from the "A" column when MAF is disabled.

    How I came about this is I put new cams which pushed me over the 10,100 alarm limit with my stock MAF. To add to this I installed a Harrop 1320 TVS which make things even worse. So I installed a larger MAF from a G6 which is giving me trouble because of the different resolution at low rpms. So I have it running pretty well on VE only but discovered the timing conundrum.

    Which would/may have been ugly at 43* timing flat out.

  4. #4
    Lifetime Member GMPX's Avatar
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    Even with the MAF missing it will still be calculating the g/cyl airflow. As the P12 seems to share code with the E40 ECM I'd be pretty confident this is what it is doing, I doubt it will be stuck at the 0.08 column.
    You test seems like a reasonable way to prove this point.
    I no longer monitor the forum, please either post your question or create a support ticket.

  5. #5
    Junior Member dennisscars's Avatar
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    You were indeed correct, luckily we were provided with Calc Engine airflow PID DYNAIR_LS2. My Son made me a PID CYL4AIR_DMA so now I can populate the spark advance and VE BEN dash page. Will be VE dyno tuning this week end.

    Would be nice to have access to cold temp adders, I can get 80#'s to work at temp but about .86 BEN before 172*F.

    Larger MAF housing seems to be scale limited at idle so am using as IAT1 sensor holder.

    By the by, I got a hoot out of how "BEN(s)" got their name!

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