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Thread: Airflow Limitation Scaling: No Need To Scale Trans Anymore!

  1. #1
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    Exclamation Airflow Limitation Scaling: No Need To Scale Trans Anymore!

    First, this may not be news to some, but it'll be a welcome read for many.

    So back in 2007, I started this thread:

    IFR Value Limit Workaround - Parameters to scale?

    Over time, that progressed into a healthy discussion on all the various parameters needing to scale in order to get around the various airflow limits within the E40 and earlier E38 PCMs. Greg Banish (eficalibrator) was instrumental in helping most all of us with this, and to more easily understand it.

    However, many of us were and are still plagued with the various 6-speed auto transmissions, in regards to tuning for them when scaling. As if scaling the multitude of the Engine side parameters referencing airflow and torque weren't enough, along comes scaling for all the various Trans parameters referencing the same. I've never had the best of luck doing this either, whereas on one vehicle it is seemingly fine, yet another the shifting is just not up to par no matter what I attempt. I've always attributed this to potentially missing parameters in the software templates that we should also be scaling.

    In early 2009, I originally asked Chris about the possibility of there being a way to scale the incoming torque signal that the TCM sees from the PCM, as seen here:

    http://www.hptuners.com/forum/showthread.php?t=21793

    I asked, "Man, what a LOT of work on the A6 vehicles. There isn't a simple scalar that could be modified in the calibration that effectively doubles the pcm's torque calculation (or whatever multiplication needed based on whatever ratio was originally used to rescale the IFR and airflow values)? Thoughts?

    It would just be really nice if there was a way to alter the torque reading going into the trans."

    Chris replied with, "ya maybe there is some way to scale the airflow used by the torque calc or the raw torque number, i dunno but that would seem the easiest way to untrick it."

    Now fast forward to early 2012, and low and behold, those parameters actually do exist, and have been found (unfortunately by the competitor first - sorry in advance for the link to their site):

    Improving shifts via the ECM

    Quote Originally Posted by GMPX
    Over the last couple of months there has been some talk in THIS thread regarding some new findings and tables for the 6 speed auto's.
    Common complaints are changed shift feel when running without a MAF, shift hanging issues with boosted engines (there's probably more to add).
    Although you can go in and change the shift pressures and desired shift times on the T43, the problem is it's own calculations are torque based. It does a lot of it's own 'thinking' based on the torque figure the ECM is reporting to it. The result of this torque figure being out usually results in the issues mentioned above.
    So how does the ECM measure engine torque? Well, it doesn't, it's calculated, and unless you change the tables used in the calculations the torque figure broadcast to the TCM is not going to be correct. Now we aren't talking to the nearest lb-ft here, but in testing we saw a drop of almost 40 lb-ft in the maximum reported torque just by going MAF-less. Ever notice how a MAF-less car doesn't shift as nice?

    So, the fix for this is not in the TCM, it's the ECM, we need to get the ECM to broadcast a more accurate torque figure of the engine for the TCM to work with. When that occurs, everything just falls in to place.

    Of course nothing is easy, there is two different torque models in use from 2006 to current.

    First the early style...



    And now the later style:




    They are very similar, but not quite the same so we gave them different table numbers.

    The calculation is along the lines of how the Virtual VE works, it takes a bunch of numbers from various tables, adds, multiplies several times over to end up with a final figure. We decided not to attempt to show these as a virtual VE table simply because there is too many variables used to be able to present it as one 3D map. However, in testing it was found there was really only one table that needed modifying to get satisfactory results. The images above show the table I mean, it's the engine Airflow contribution to the final torque figure.

    I will quote from the table descriptions....
    "Modifying coefficient values should be done with caution. Sometimes small changes in the table may cause big changes in the final calculated values. It is recommended that you change the values by only 5% at a time and then test the results. The final torque value from the Torque Model tables can be logged in the scantool using the PID - GM.TRQENG_C "Engine Actual Steady State Torque".

    Note: Don't be too concerned about the shape or smoothness of this map as it is a coefficient table, they tend to look erratic. Applying smoothing to make it look 'nice' may have negative results."


    There is really only one way to verify your changes, monitor the reported torque value using the scantool PID GM.TRQENG_C "Engine Actual Steady State Torque".

    All these updates have been included from RC10 up.

    Please post up your results for others to use as a guide.
    Basically, whatever we are scaling our engine airflow and torque based parameters by, we should also be increasing by the same to this Torque Model table(s), and this will prevent us from having to scale any of the various airflow and torque tables on the Trans side. Take a gander at this thread below, specifically the "fix" in post #12 of it:

    T43/E38 Scaled Shifting

    Quote Originally Posted by swingtan
    1. You've scaled the normal air flow tables down by an assumed 60% to suit the ID1000 injectors. So you need to start with increasing B3033 by at leas the same amount just to suit the stock motor.
    2. You've made additional changes to the tune to increase the stock power, so you need to add to B3033 to match the power increases.
    3. You're have already, or are about to boost the motor, significantly increasing torque, so this table again need further increases to match.


    What I'd do is start with fairly standard settings for the auto, and work on B3033 to get the box shifting somewhat correctly. Then fine tune with the trans tune. It may require some back and forth between the trans tune and the ECM tune to get it perfect, but that's how I'd address any shifting issues.
    But there's also more than just the scaling benefit we'd gain from these parameters, as you've obviously determined by now after reading through that first thread (hopefully you did), one being with the Mafless conversions, and another with vehicles where we just add any significant amount of power to via modding. Tuning these parameters for them *should* be decently capable, and Greg Banish touched on that in his post (#50) on the "Improving shifts via the ECM" thread I linked to above:

    Quote Originally Posted by eficalibrator
    Call me crazy, but I think an easy way to get these tables in the ballpark really quick would be to log the torque estimate resulting from the coefficients (see post #1) during a WOT run that starts from very low RPM. Then you could compare the CALCULATED torque to a reasonable engine torque calculation from the dyno (corrected from wheel torque) and come up with a single rough correction factor at each RPM breakpoint.

    Then, instead of multiplying the whole table by some unknown factor, you could have a series of RPM-specific corrections. Each one would be applied to its own RPM row and all of them would get applied in a single ECU flash.

    Then just re-run the WOT pull and see how close you got it across the RPM band. Like he said earlier, you don't need to be precise, just "close enough". This should take a bunch of the guesswork out of the calibration process and speed things up by avoiding the mindless poking about of constantly trying different random correction factors across the board until it "feels right." You should be able to get close in one or two carefully measured corrections.
    Now all we have to do is sweet talk Chris and the gang into also adding these parameters for us HPT junkies (purty please, Chris?!).
    Last edited by RWTD; 02-07-2013 at 09:25 AM.
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  2. #2
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    I had talked to Chris about this some time ago. The main problem, from my understanding, is that if the ve tables are not properly calculated it can throw everything off which is why he hasn't added it as of yet.
    It doesn't have to be perfect, it just needs to be done in two weeks...

    A wise man once said "google it"

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    I have read the EFI thread with interest a while back and wondered why we couldnt try it in HP tuners. They seem to be having success with it.
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  4. #4
    yes i have known about the tables for a long time, it requires the background math code from virtual VE to do it the way i want and i am still waiting for that to be implemented. Same with some idle stuff i would also like to add.

    I can add the raw tables easily enough in the meantime.

    Chris...
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    Quote Originally Posted by Chris@HPTuners View Post
    yes i have known about the tables for a long time, it requires the background math code from virtual VE to do it the way i want and i am still waiting for that to be implemented. Same with some idle stuff i would also like to add.

    I can add the raw tables easily enough in the meantime.

    Chris...
    Brilliant! Thank you so very much, sir. Me first? LOL, j/k!
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    post up a few OS's you want and i'll do them first
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    Quote Originally Posted by Chris@HPTuners View Post
    post up a few OS's you want and i'll do them first
    Thanks so much, Chris! How about 12617631 (2008 C6 A6), 12614676 (2007 C6 A6), and 12605732 (2006 C6 A6). There's also 12605740 and 12598983 (both 2005 C6 A4), if you'd like to get whichever is newer of those, as well.
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    cool, I use the great A6 tuning tables from HPtuners and just starting using this table in our EFILive setup for scaled tunes....will be great to stay with one cable

    Thanks Chris and Bill

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    Quote Originally Posted by Chris@HPTuners View Post
    post up a few OS's you want and i'll do them first
    I need this..... 12614676 (2007 C6 A6) I converted to the 2 bar map OS if that makes any difference.
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    Quote Originally Posted by realcanuk View Post
    I need this..... 12614676 (2007 C6 A6) I converted to the 2 bar map OS if that makes any difference.
    I listed that above.
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    Quote Originally Posted by RWTD View Post
    I listed that above.
    I know. I copied and pasted it.

    I was just not sure if the upgrade to 2 bar makes a difference.
    2007 Corvette C6 Vert. A6
    LME LS402, Pat G custom cam, ATI 10% OD Damper
    Circle D triple disc 2600, 3.42 Diff
    YSI, 3.0 pulley, ID 1000's
    Alky Control Meth,
    ARH 1 7/8 headers,
    1009 RWHP @ 7000, 817 RWT @ 6000

  12. #12
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    Quote Originally Posted by realcanuk View Post
    I know. I copied and pasted it.

    I was just not sure if the upgrade to 2 bar makes a difference.
    Open your cal and view the OS info and post it up.
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    shouldn't make a difference, what he'll do is add it to the base os def ie 12614676 and it'll automatically show up in the custom operating system for that os.
    It doesn't have to be perfect, it just needs to be done in two weeks...

    A wise man once said "google it"

  14. #14
    ok the E38 OS's listed have been added to 2.23.861 or later.

    we'll start adding them to all E38/67 etc. over the coming weeks.

    The E40 is different so i'll look into those another time.

    Chris...
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    Thanks Chris...

    Lets start testing...

    2007 Corvette C6 Vert. A6
    LME LS402, Pat G custom cam, ATI 10% OD Damper
    Circle D triple disc 2600, 3.42 Diff
    YSI, 3.0 pulley, ID 1000's
    Alky Control Meth,
    ARH 1 7/8 headers,
    1009 RWHP @ 7000, 817 RWT @ 6000

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    Chris can you add 12614682 (2006 C6 E38)

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  17. #17
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    Quote Originally Posted by Ben Charles View Post
    Chris can you add 12614682 (2006 C6 E38)
    Yowsers, yeah I screwed that up previously by giving Chris an '06 M6 OS instead of the A6 OS (what you listed). My apologies. I'm sure Chris will add it in soon (my bad, Chris).
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  18. #18
    any hope for the E40? 12604792?

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    Greg was at our shop this weekend and we continued our conversation about properly remapping the torque coefficients...We are now able to tie our chassis dyno torque reading into our software and use a correction factor based on measured torque to be able to better remap these tables....of course is a down and dirty method but its about as close as we can get.

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    Check out post 115 here. I know nothing about programming but if someone can get a spreadsheet to work like that and give a proper torque output by inputting the variable, I for one, would be happy to donate for the time involved.

    http://forum.efilive.com/showthread....the-ECM/page12
    2007 Corvette C6 Vert. A6
    LME LS402, Pat G custom cam, ATI 10% OD Damper
    Circle D triple disc 2600, 3.42 Diff
    YSI, 3.0 pulley, ID 1000's
    Alky Control Meth,
    ARH 1 7/8 headers,
    1009 RWHP @ 7000, 817 RWT @ 6000