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Thread: Calc.MAFT: correcting VE and calculating MAF (in single log) --> reverse of Calc.VET

  1. #31
    Joe (Moderator) joecar's Avatar
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    Hi Shawn,

    Thanks for updating...

    I made a minor edit to point 3.

    Also, should point 5. (filtering) be done before points 3. (CALC.SELBEN->B0101) and 4. (CALC.MAFT->B5001)...?

    On your maps, show the units.


  2. #32
    Joe (Moderator) joecar's Avatar
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    Hi Shawn, I made another minor edit, I swapped the text between steps 4. and 5. to match the pics.

  3. #33
    Joe (Moderator) joecar's Avatar
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    Shawn, also, the MAF has to be disabled.

  4. #34
    R.I.P Shawn, 1956-2011 WeathermanShawn's Avatar
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    Well pretty much completed all the testing on CALC.MAFT, and it works quite well.

    Did about a half-dozen runs, some MAF-Enabled (for comparison) and MAF Disabled.

    Compared CALC.MAFT formula: "{GM.VETABLE_DMA.VE}/{CALC.DAT.K}*{SAE.MAP.kPa}*{SAE.RPM}/15" vs the following Airflow Pids: (All in g/s units).

    "{GM.DYNCYLAIR_DMA}*{SAE.RPM}/15"

    "{GM.CYLAIR_DMA}*{SAE.RPM}/15"


    "{GM.DYNCYLAIR}*{SAE.RPM}/15"


    “{GM.DYNAIR}


    Results: CALC.MAFT equation was superior. It accurately reflected the VE/MAF Airflow relationship instantaneously and with no 'filtering'.

    The various Airflow Pids all reflect a subtle filtering and averaging in their results. The DMA Pids also reflect a slight difference vs DYNAIR.

    Conclusion: The CALC.MAFT equation most accurately reflects the direct relationship between the VE Table vs MAF Airflow/Frequency. The Airflow Pids can be substituted, but during Throttle Transitions the averaging/filtering components show an inconsistency vs CALC.MAFT.

    Bottom line is that it can be a very exhausting and time-consuming study to substitute Airflow Pids as a Tuning method for the MAF. IMO, the CALC.MAFT represents the best approach to Tuning the MAF directly from a known VE Table.
    Last edited by WeathermanShawn; May 31st, 2011 at 11:47 PM.
    2002 Black Camaro Z-28 M6 Hardtop 11.0:1CR 425HP/410TQ SAE (400TQ@3500RPM)
    200cc Heads, 228/232 110+2 Cam, 1 3/4" LT's w/catts, GMMG, Koni Shocks, Hotchkis Springs, 35/21 Sways, 17" ZR1's, 3.90 Gears Roadrunner PCM LM-2 Serial Wideband
    EFILive Closed-Loop MAF/SD Hybrid Tune..


  5. #35
    Joe (Moderator) joecar's Avatar
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    Good deal

  6. #36
    Lifetime Member Mr. P.'s Avatar
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    OK I have looked over the suggested calc_pids.txt file in Post #1, and question something:

    joecar you express CALC.PE as: "{GM.EQIVRATIO} > 1 && {SAE.RPM} > 1000"

    Shouldn't it instead be: "{GM.EQIVRATIO} <> 1 && {SAE.RPM} > 1000"? In my commanded AFR table I use 0.99 to prevent going into closed-loop as I log & do my VE table tuning.

    Also, this seems to me to be more a function that determines when the PCM is in open or closed loop (versus whether it is in PE mode or not); and that's fine, I get it, you want to know when the PCM is updating TRIMs and leverage the feedback of those TRIMs during those windows of time when the PCM is calculating/updating them, and that happens when commanded EQR = 1.000, right??

    Mr. P.
    Last edited by Mr. P.; June 2nd, 2011 at 04:02 AM.
    2003 Silverado SS, with Novi-1500 "CAI mod"
    EFILive V 7.5 COS-3 (OLSD, for now!)

  7. #37
    R.I.P Shawn, 1956-2011 WeathermanShawn's Avatar
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    Mr. P, quit asking tough questions!.

    Joking of course..We have been trying to figure out a better Pid for PE Mode, but so far no luck. Obviously, you can change any of the Calculated Pids to your own definition. As you stated, this one is designed to know when Trims are being applied, and when they are not.

    You can try what you are asking..if that does not work try a PM to JC..its a good question, a little out of my area of expertise..
    2002 Black Camaro Z-28 M6 Hardtop 11.0:1CR 425HP/410TQ SAE (400TQ@3500RPM)
    200cc Heads, 228/232 110+2 Cam, 1 3/4" LT's w/catts, GMMG, Koni Shocks, Hotchkis Springs, 35/21 Sways, 17" ZR1's, 3.90 Gears Roadrunner PCM LM-2 Serial Wideband
    EFILive Closed-Loop MAF/SD Hybrid Tune..


  8. #38
    Joe (Moderator) joecar's Avatar
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    Quote Originally Posted by Mr. P. View Post
    OK I have looked over the suggested calc_pids.txt file in Post #1, and question something:

    joecar you express CALC.PE as: "{GM.EQIVRATIO} > 1 && {SAE.RPM} > 1000"

    Shouldn't it instead be: "{GM.EQIVRATIO} <> 1 && {SAE.RPM} > 1000"? In my commanded AFR table I use 0.99 to prevent going into closed-loop as I log & do my VE table tuning.

    Also, this seems to me to be more a function that determines when the PCM is in open or closed loop (versus whether it is in PE mode or not); and that's fine, I get it, you want to know when the PCM is updating TRIMs and leverage the feedback of those TRIMs during those windows of time when the PCM is calculating/updating them, and that happens when commanded EQR = 1.000, right??

    Mr. P.
    That (EQR 0.99) prevents it from doing STFT trimming while in open loop (which is a feature of the COS's, and is enable-able on the non-COS's via B4206).

    Yes, exactly... we're trying to find a better way of determining CL/OL.

  9. #39
    Joe (Moderator) joecar's Avatar
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    We may change the PE pid to be a CL pid... after logging a few STATExx pids, it seems we'll have to make a calc pid that uses FUELSYS to determine CL/OL.


    I've been logging STATE05 and I see this:
    - fuel state shows CL all the time after operating temp is reached;
    - DFCO never triggers;

    both of those are obviously incorrect.

  10. #40
    Lifetime Member Mr. P.'s Avatar
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    Quote Originally Posted by WeathermanShawn View Post
    Mr. P, quit asking tough questions!...
    Lol yeah I'm a PITA that way; blame the developer in me. I'm good at tearing stuff apart, just not always so good at putting it back together!

    Quote Originally Posted by joecar View Post
    We may change the PE pid to be a CL pid... after logging a few STATExx pids, it seems we'll have to make a calc pid that uses FUELSYS to determine CL/OL.


    I've been logging STATE05 and I see this:
    - fuel state shows CL all the time after operating temp is reached;
    - DFCO never triggers;

    both of those are obviously incorrect.
    I totally understand your strategy, you want to leverage TRIMS and those are 'live' only when the PCM is in closed loop.

    BUT - I thought there was already a PID which told us whether the PCM was in CL or not, because I remember when I first purchased EFILive years ago and I stepped through the tutorial there was a PID whose value was "CLOSED" or "OPEN", I remember exporting it and looking at the data because my truck runs f'n awesome when you first start it (value was "OPEN" and spark was dead steady) and then after 30-seconds or so the motor idled like crap and the spark randomly jumps all over the place and that PID displayed "CLOSED"...

    In both the GM and custom operating systems it is True that when they are in CL operation the commanded EQR will be 1.00; however the converse is *not* True (that when EQR = 1.00 the PCM is in CL) because there are a few special situations where the PCM will command 1.00 EQR and be in OL (like at cold startup and restart, when the O2s are cold). But I think in the 'sandbox' we are working in, I would stick with your initial strategy, have your custom PID return a True value when EQR = 1, but I would rename that variable CALC.CLOSED_LOOP or CALC.DO_USE_TRIMS or something like that, but that's admittely nit-picking and a very minor suggestion.

    I will go back and look for that closed/open loop variable I saw years ago, but I would not use it because that's just 2 more bytes [channels] eaten-up in your data stream when you can determine the same value from the commanded EQR you are already logging.

    Mr. P.

    PS - on the point you made about B4206, thanks did not know the PCM's OS acted like that - I did not know the PCM would update STRIMS in open loop, for some reason I had it in my head that TRIMS only updated when in closed-loop. ???
    Last edited by Mr. P.; June 3rd, 2011 at 03:07 AM.
    2003 Silverado SS, with Novi-1500 "CAI mod"
    EFILive V 7.5 COS-3 (OLSD, for now!)

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