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Thread: Calculated HP PID?

  1. #1
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    Default Calculated HP PID?

    Not the one that EFILive comes with, I wonder if anyone made one that uses the engine's calculated torque to math out calculated hp? It's pretty easy to see your range of peak torque with the dyncylair_dma PID, would be nice to see when hp is falling off as well. I don't care what number it spits out, just looking for the curve. The included PID is rate of change of speed over time IIRC and can be affected by a gust of wind and all sorts of things.
    1998 GMC Sierra K1500 5.7/4L80E, longtubes, 411 w/COS 5, marine cam/intake, Whipple. 91 octane at 6000'.
    1997 GMC Sierra K3500 7.4/4L80E, 411 w/COS 3, Whipple, small cam.
    2004 Corvette Z06 with longtubes.

  2. #2
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    Alright, I think I just made one. Probably doesn't work, never done this before. Open kimono, I never left the old 7.5 scanner software even though 8.0 is on my machine. So I just went into 8.0 and made a custom PID group and a custom PID under it. Here's the syntax:

    -- MINE.WHP
    "PCM.TRQENG*PCM.RPM/5252"
    return 0

    I suspect I have a bit more to configure before I can go out and log on V8 all the things I do on 7.5, but I wasn't seeing a way to do this on 7.5 and it's not showing up in the 7.5 PIDs. In the meantime, if you happen to see this before I post a log, please let me know if I've missed something obvious creating that PID.
    1998 GMC Sierra K1500 5.7/4L80E, longtubes, 411 w/COS 5, marine cam/intake, Whipple. 91 octane at 6000'.
    1997 GMC Sierra K3500 7.4/4L80E, 411 w/COS 3, Whipple, small cam.
    2004 Corvette Z06 with longtubes.

  3. #3
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    After looking at other calculated PIDs, I came up with this:

    -- MINE.WHP
    return pid"pcm.trqeng"*pid"pcm.rpm"/5252;

    Not sure if I need parenthesis for individual PIDs?
    1998 GMC Sierra K1500 5.7/4L80E, longtubes, 411 w/COS 5, marine cam/intake, Whipple. 91 octane at 6000'.
    1997 GMC Sierra K3500 7.4/4L80E, 411 w/COS 3, Whipple, small cam.
    2004 Corvette Z06 with longtubes.

  4. #4
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    Last night I had an issue with connectivity with my Z06. Key on engine off, V8 would display data. Fire the car up and it would instantly die. Showed o hp with the engine off, so was hopeful it'd work. Tried today on my truck and V8 worked just fine, but my PID was stuck at 0. Must be a syntax error. I'd updated it to show ft/lb, but may have to undo that since I can display PCM.ENGTRQ as ft/lb. Here's what it looks like now:

    -- MINE.WHP
    return pid"pcm.trqeng"/1.356*pid"pcm.rpm"/5252;

    If there's a primer on syntax anywhere, I'd really appreciate a nudge in the right direction because I can't find jack shit with google or the search function. Looking at the calc.vet thread, maybe I should try something more like this?

    -- MINE.WHP
    return {pcm.trqeng}/1.356*{pcm.rpm}/5252;

    It looks like units were also baked into it from the get go, where's the legend to what abbreviation equals what units? Do I need parenthesis since order of operations would prevent this from getting messed up? According to some quick math, if the PCM is correctly calculating torque going up or down, I'm making more hp at 5300 than 5000. With my cam the truck shouldn't want to shift much north of 5000. Maybe the blower is keeping it going? Torque is falling off pretty hard, but the hp seems to still be going up. Would be nice to have a PID show me that to help determine the appropriate WOT shift point.
    1998 GMC Sierra K1500 5.7/4L80E, longtubes, 411 w/COS 5, marine cam/intake, Whipple. 91 octane at 6000'.
    1997 GMC Sierra K3500 7.4/4L80E, 411 w/COS 3, Whipple, small cam.
    2004 Corvette Z06 with longtubes.

  5. #5
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    As usual, I didn't read far enough.

    https://www.efilive.com/latest/creat...lculated-pids/

    I saw boolean and bailed, I wanted a calculated output not a yes/no filter. What about if/or/else statements though? If I try doing anything cooler than this I'm going to get stuck again pretty quickly. Here's the syntax that worked.

    -- MINE.WHP
    return pid("PCM.TRQENG")/1.356*pid("PCM.RPM")/5252;

    I didn't test it out before, that would have saved me some trouble. Didn't realize that function existed. It needed parenthesis after all (and the correct case, but I just clicked the PIDs from the menu on the right this time). And since I assume this starts life in nm, the numbers come out correctly with my nm/ftlb conversion even though I display calculated torque in ft/lb. It looks like I may have shifted right at peak hp, going to run it out 200 more to see what it says.
    1998 GMC Sierra K1500 5.7/4L80E, longtubes, 411 w/COS 5, marine cam/intake, Whipple. 91 octane at 6000'.
    1997 GMC Sierra K3500 7.4/4L80E, 411 w/COS 3, Whipple, small cam.
    2004 Corvette Z06 with longtubes.

  6. #6
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    dont you like "the one that EFILive comes with"? does it work for you (in a realistic way)? after all is based on the acceleration.

    while dyncylair is some calculated value. good for comparative analysis, but absolute numbers? and my trqeng does very strange things.

  7. #7
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    Quote Originally Posted by dian View Post
    dont you like "the one that EFILive comes with"? does it work for you (in a realistic way)? after all is based on the acceleration.

    while dyncylair is some calculated value. good for comparative analysis, but absolute numbers? and my trqeng does very strange things.
    The one it comes with wasn't helpful in determining shift points. I don't care what the number is, I just wanted to see where peak was.
    1998 GMC Sierra K1500 5.7/4L80E, longtubes, 411 w/COS 5, marine cam/intake, Whipple. 91 octane at 6000'.
    1997 GMC Sierra K3500 7.4/4L80E, 411 w/COS 3, Whipple, small cam.
    2004 Corvette Z06 with longtubes.

  8. #8
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    so you are analysing the trans? i thought you were after horsepower. trqeng supposedly controlls torque signal pressure. i suspect there is more to it, like first derivative of tp maybe.

    i started logging line pressure recently and looking at it and force motor (pcs) pressure (=torque signal/tfmprs) i dont see a consistent correlation with trqeng. seems better with dyncylair just looking at it. my trqeng is fine with the car in stock configuration but acts up with cos3 and boost (centri). are you finding the same? i asked about it on here not so long ago.

    my tfmps is far from adhering to what im comanding in d0701-3. and the relation between it and line pressure is another story still.

    e.g.: max tfmprs occuring is 580 kpa. it can be all in between 360nm and 710nm, altough i command it to this level by 435nm. no use maxing out the table to the 662kpa also. line, btw, is around 13 bar (200psi) max.
    Last edited by dian; November 12th, 2023 at 09:29 PM.

  9. #9
    Joe (Moderator) joecar's Avatar
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    Don't forget that the torque converter decouples any correlation between engine and trans calculations.

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