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Thread: SD tuning for E38/E67 ECM's

  1. #81
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    Spreadsheet and How to solve for clean boundaries ?

    Hi there- the link below is no longer working. Carneb, would you be willing to upload it again for us or can someone that downloaded it previously email it to me ? Also, when you have XLFit solve for the parameters, does it simply do each zone in isolation or do you/can you tell XLFit to solve for the parameters under the constraint of hitting the edge figures exactly (or to a close tolerance) so that there is no ugliness at the boundaries of the zones ?


    Thanks, Dean


    Quote Originally Posted by carneb
    I've found an Excel add-in called XLFit. I've changes the spreadsheet to include this and to tidy it up. You can copy the coefficients from HPTuners and paste onto the "Original Coeff" sheet. This will graph the VE table and show the table on the "Original VE" page. After logging the car you can then copy and paste the AFR % error from HPTuners into the "AFR % error" sheet, assuming the row and column titles are the same. The AFR % error data will adjust the VE table. The adjusted table is shown on the "New VE" sheet and the new coefficients and graph on the "New Coeff" sheet. You can then copy and paste the new coefficients back into HPTuners and then go and do some more logging.

    The problem is that you can only use XLFit for 30 days before having to pay and it's not cheap. If you want to have a look it is here http://www.idbs.com/Decision/XLfit/ . Unfortunately the spreadsheet won't work properly without installing XLFit.

    If you are going to play with the spreadsheet please note that it has not been tested in real world conditions so make sure the figures look sensible before using them.

    Here is the Spreadsheet. http://users.bigpond.net.au/bcar4179/e38_e67 sd ve tuning afr.xls It is now around 1 MB
    Last edited by deanm11; 09-19-2007 at 04:51 AM.

  2. #82
    Tuner carneb's Avatar
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    Quote Originally Posted by deanm11
    Hi there- the link below is no longer working. Carneb, would you be willing to upload it again for us or can someone that downloaded it previously email it to me ? Also, when you have XLFit solve for the parameters, does it simply do each zone in isolation or do you/can you tell XLFit to solve for the parameters under the constraint of hitting the edge figures exactly (or to a close tolerance) so that there is no ugliness at the boundaries of the zones ?


    Thanks, Dean
    Try this http://www.ls1-australia.com/vetunin... Table AFR.xls
    VE Calais V 6.0L L98 V8 6L80E

  3. #83
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    Quote Originally Posted by carneb
    Absolutely amazing! Great find.
    Formerly known as RWTD

    Toys: '22 Tesla Model S Plaid / '20 Chevy Duramax / ?20 Sea-Doo RXT-X (2)

  4. #84

  5. #85
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    Quote Originally Posted by checkmate
    My head hurts.
    mine even more
    05 Yellowjacket GTO M6
    too many mods
    big cam untuned

  6. #86
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    Quote Originally Posted by Chris@HPTuners
    ya you need the matrix solver, looks like they beat us to the punch. oh well at least they didn't choose the same name as we did
    I'm reading up before attempting to mess with LS3. Did this get implemented so that changing VE no longer requires the spreadsheet plus the add-in?

  7. #87
    Advanced Tuner Bluecat's Avatar
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    In case you haven't ran across this thread...

    http://www.hptuners.com/forum/showthread.php?t=14558

  8. #88
    wow, thanks guys, very useful and interesting thread

    Quote Originally Posted by Chris@HPTuners
    4. *the difficult part* using a math program such as Matlab or crazy amounts of trial and error solve the VE table raw data into the coefficients. ie. this is a solving matrices problem - hence Matlab or equivalent. This amounts to solving each of the 30 simulataneous equations for the 14 coefficents.

    eg. Ax² + By² + Cxy + Dx + Ey + Fxy + G = VE

    You know what VE needs to be (the AFR % error tells you this) and you know x and y (MAP & RPM) so solve for A,B,C,D,E,F,G and repeat 30 times, simultaneously. Scary huh. You really do have to recalculate *ALL* the coefficents, although some may not change much, it is critical that crossing zone boundaries is continuous.
    unclear about something, in what sense are 30 equations simultaneous? each has its own coefficients A_z, B_z, etc, indexed by zone z, so equations are zone-independent and seems to me this is actually pretty easy if one has some trim data, since the data is directly segregated into zones. all one needs to do is use some decent numerical software to fit a quadratic function over each zone separately, given a good number of data points (rpm, map, target VE(rpm, map)) in each zone.

    as far as continuity, one has no control over how resulting VE functions patch and seems to me one should let them fall where they may. can't expect simple quadratic functions to respect zone boundary conditions. i bet even the factory VE functions have noticeable steps across some zone boundaries. or am i missing something?

    -alex

  9. #89
    ok, never mind, i see...

  10. #90
    So Chris any news on the feature you mentioned you guys are working on? ("Virtual VE")

    thanks!

  11. #91
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    So I "think" I have a handle on how this works ... For my engine ('08 6.2L VVT w/ MagnaCharger TVS1900 @ 6#) I still have the one BIG unknown ... Cam Angle ... any chance this is coming soon? Can you just post the calculations for cam angle based on load, rpm, tps etc ... whatever it may be calculated on so that I might be able to calculate the angle?
    From the one VCP table available (spark) I don't see any way around properly tuning the VE except for running pure MAF which I understand works in general but I would rather use both in my application.
    Thanks in advance for the help!

  12. #92
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    I'm going to blindly chime in here after looking at only a few select posts. But Honda motors already run on cam angle and map readings, it might be beneficial to read up on tuning through what they call "Kpro" for some of the information and/or tables that might help.

  13. #93
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    It's alive!!! So what's new since 2007?
    Darryn

    2009.5 Blue G8GT

  14. #94
    Quote Originally Posted by Chris@HPTuners View Post
    I haven't updated the help files yet for the new SD parameters, but here's a simlified view for those vehicles that don't have variable camshaft or switched (active) intake manifold.



    As you can see it is far from simple

    The way this kind of thing is typically done in a mathematical sense is you create the solution matrix that they are trying to achieve (ie. in this case the multi-dimensional VE table). Then put that into a math package like Matlab etc. that then churns out the filter coefficient matrix, which is then put into the calibration tables.

    It is completely non-intuitive, but you could construct a spreadsheet or something to calculate the VE value at given RPM and MAP values for any set of coefficients (using the formula above). For those 4cyl guys who have variable camshaft your world is another 2 orders of magnitude more complex) becuase the Intake and Exhaust cam terms are not zero.



    If you open an early E38 file, under Engine Airflwo, Dynamic Airflow you will see the zone mapping thresholds and numbering.

    For the later code they eliminated the ability to map the zone #'s but the convention is the same as below.



    Now most of you are wondering, why, for the love of god, would anyone think this is a better system than before? The answer is simple really, this mathematical approach gives a highly accurate result in the new multidimensional space created by adding the exhaust, intake camshaft and also the variable intake systems. For example, to do this the traditional way would require multiple VE tables for each camshaft, then some mehtod to mix the result and then another set of VE tables for each depending on the switched manifold state, not to mention you have DoD thrown in as well. ie. the old way being conservative assuming 5 VE tables for each cam position, three differnt states for the manifold switch and a couple of states for DoD. gives a total of 5 x 5 x 3 x 2 = 150 VE tables and then you still have a giant interpolation mess to deal with at the end. Not to mention you just blew out the size of the calibration a huge amount.

    Unfortunately folks this is the way of the future, and this aspect of the PCM control is not the only thing headed this way - things like torque estimation, idle control and throttle control will all go this way eventually. Makes you wish you had paid attention in those engineering math classes

    So where to begin?
    So far you should have realized that the constant term is the only remotely intuitive part to the equation. Modifying these numbers effectively offsets each zone of the VE table up or down. ie. if you increase the constant term the VE value increases and the PCM will add more fuel. However, be warned that as soon as you change anything, the transition boundaries between zones will be out so don't move things too much or unexpected things may happen. The linear terms suchs as KMAP and KRPM multiply the current value of RPM or MAP, then you have the quadratic terms such as KMAP² and KRPM² which operate on the square of the MAP or RPM. You'll notice that these numbers are very small or zero, putting large numbers here will create major problems and/or instability.

    You will also notice that in some cases the coeffcients are negative numbers, there's no reason they can;t be negative, it's just a mapping to a final result after all.

    The good thing here is that in theory you can run 2bar without any operating system mods as the SD zones can be setup for boost as well, in fact some of the northstar engine calibrations do just that.

    Good luck,

    Chris...

    PS. after SEMA i will put as much detail in plain english as possible in the help files, although i have struggled to even explain it to myself and i know the thoery and mathematics behind this stuff quite well.
    Just so I can be clear with this, are the periods in your equation multiplication? Ex:

    A*B*C=D
    equivilent to
    A.B.C=D ?

    And when you mean KMap.Map^2
    do you mean K*Map*MAP^2?
    or the constant of map times map squared?
    KMap*Map^2 ?

    I want to enter this into matlab and make a program for myself. Thanks Chris!
    Chris

  15. #95
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    if you're using matlab, just use the x2fx function, with the 'quad' model parameter

  16. #96
    Quote Originally Posted by redhardsupra View Post
    if you're using matlab, just use the x2fx function, with the 'quad' model parameter
    Ok I just searched in Matlab and I got it, I love their help files they are very informative for functions I am not familiar with. Thanks.
    Chris

  17. #97
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    any update?

  18. #98
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    Wow I am in math class again....

    Thanks,
    Mr. 2008 SS
    E-Fans*160 Stat*K@N Filter* FlowMaster Catback Duals*HP Tuned By Me USA

  19. #99
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    Labels RPM Zone 0 RPM Zone 1 RPM Zone 2 RPM Zone 3 RPM Zone 4
    MAP Zone 0-1 30.0 25.0 21.0 21.0 21.0
    MAP Zone 1-2 45.0 45.0 45.0 45.0 45.0
    MAP Zone 2-3 60.0 60.0 60.0 60.0 60.0
    MAP Zone 3-4 75.0 75.0 75.0 75.0 75.0
    MAP Zone 4-5 90.0 90.0 90.0 90.0 90.0

    Sorry I couldn't seem to get my screen shot function to work on this computer, but..

    Is this right for what my dynamic MAP boundary table should be? I haven't made any changes to it, but most of the other tables that are posted in this thread start at "0" in the top left, and end up at "29" in the bottom right, numbered vertically? I'm struggling to make the corrections I need, and have already found a couple temperature tables in this tune file that were labeled really strange. Could this be why nothing seems to react the way I think it should when trying to tune?
    Its from a 2010 A6 Camaro.

  20. #100
    Tuner in Training AGamble's Avatar
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    wow I thought electronic engineering formulas were a challenge, I think my brain waves just flat lined. I am going to need a lot more training to catch up with y'all. I have been researching all the forms I can find, I won't even touch my LS3 tune until I learn more. I bought the pro, but it looks like I need a lot more info and a wideband. Any direction I can get would be appreciated.