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Thread: tune plotting

  1. #1
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    Default tune plotting

    done decent amount of dmax stuff messing with gas now.. one thing I learned there is a flow chart on how the ECM processes info..
    diesel was pretty simple.. it was TPS/RPM=fuel volume(MM3) then just about every table was based of one of those three values TPS, RPM, fuel volume

    I know all the major tables are either based of VE/RPM/engine load or vacuum but have been able to connect all the dots...

    why does B0101 go up to 15.2psi and just about every timing table stops are 11.6psi, like B3701 or B4001?
    what does 15.2psi in EFI live correlate to in either PSIG or PSIA? there a table?
    what does OZ/cylinder numbers reference? like table B3639 what does .020 correlate to?

    im guesing OZ/cylinder numbers from .003 to .042 denote engine load or manifold vacuum but have yet find the table that denotes said values
    this definition was on B4001
    "It is based on manifold absolute VACUUM, where:
    0 kPa vacuum indicates atmosphere and
    80 kPa vacuum indicates atmosphere less 80kPa which, at sea level, is 101.3-80 = 21.3 kPa MAP."
    21.3kPa is ~7psi

    does 20inHg gauge vacuum equals what in EFI live 6 or 34? guesing its 6 since 30inHg is a perfect vacuum.... that begs the questions...where's WOT on the table or 0inHgG
    i know the VVT dmax trucks, boost is command in absolute values.. 30psig of boost is 45psi on in tables

    trying to figure out how they wrote it.


    ada,

  2. #2
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    maybe I failed at articulating my question...
    using table B5913 its using RPM and OZ/cyl to get/depict a timing value. what does collum information/value come from? the .011 .013, .014 etc numbers come from?
    Educated guess is top left is idle bottom right is WOT
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  3. #3
    Joe (Moderator) joecar's Avatar
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    Hi mal,

    Quote Originally Posted by malibu795 View Post
    ...
    why does B0101 go up to 15.2psi and just about every timing table stops are 11.6psi, like B3701 or B4001?
    what does 15.2psi in EFI live correlate to in either PSIG or PSIA? there a table?
    what does OZ/cylinder numbers reference? like table B3639 what does .020 correlate to?
    In gasoline tuning (and diesel tuning) the convention is to use kPa units for any pressure related to intake air.

    So the MAP axis on B0101 runs up to 105 kPa;
    note that 100 kPa represents approximately (but very closely) 1 atmosphere (1 bar);
    note that MAP is Manifold Absolute Pressure (i.e. not gauge pressure).
    So B0101, B3701 only run up to just barely past 1 atmosphere, i.e. 105 kPa (so we have to do special thins to tune for boost).

    The axis on B4001 on GenIII is vacuum, i.e. BARO - MAP (and on GenIV and GenV is deltaMAP which is defined as the pressure delta across an injector (top - bottom)).

    The axis on timing tables B5913, B5914 is g/cyl (or simply just g, the /cyl being implied); this is the cylinder airmass fill in grams.

    Same with B3639 (note that you should not be using Lean Cruise except under very particular circumstances).


    im guesing OZ/cylinder numbers from .003 to .042 denote engine load or manifold vacuum but have yet find the table that denotes said values
    Engine load yes, vacuum no, cylinder airmass yes.

    (use g instead of oz)


    this definition was on B4001
    "It is based on manifold absolute VACUUM, where:
    0 kPa vacuum indicates atmosphere and
    80 kPa vacuum indicates atmosphere less 80kPa which, at sea level, is 101.3-80 = 21.3 kPa MAP."
    21.3kPa is ~7psi
    Yes, correct (use 100 kPa for BARO, it is very close and easier to calculate with).


    does 20inHg gauge vacuum equals what in EFI live 6 or 34? guesing its 6 since 30inHg is a perfect vacuum....
    that begs the questions...where's WOT on the table or 0inHgG
    20 inHg gauge vacuum (stock idle, 35 kPa MAP, 65 kPa VAC) is 2/3 of the way between 0 inHg (WOT, 100 kPa MAP, 0 kPa VAC) and 20 inHg (perfect vaccum, 0 kPa MAP, 100 kPa VAC).


    i know the VVT dmax trucks, boost is command in absolute values.. 30psig of boost is 45psi on in tables
    Anything above 1 bar (15 psiA (close approximation to 14.5 psiA), i.e. 100 kPaA) is boost... it is easier to be consistent and use absolute pressure.

    Units:
    For pressure use kPa, for mass (air or fuel) use g, for flowrate (air or fuel) use g/s.
    For fueling unit use EQR, not AFR (to keep fueling independent of fuel being run).


    Also note: keep airmass separate from fueling.


    More info (see posts #4, #29, #38): Summary-Notes
    Last edited by joecar; November 10th, 2018 at 07:12 AM.

  4. #4
    Joe (Moderator) joecar's Avatar
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    Quote Originally Posted by malibu795 View Post
    maybe I failed at articulating my question...
    using table B5913 its using RPM and OZ/cyl to get/depict a timing value. what does collum information/value come from? the .011 .013, .014 etc numbers come from?
    Educated guess is top left is idle bottom right is WOT
    The column axis is the PCM's calculation of cylinder airmass (you're viewing as oz; change your units to g).

    top left region: idle.

    rightmost column: WOT (you can have WOT at any RPM).

    bottom right region: WOT at redline/screaming RPM.

  5. #5
    Joe (Moderator) joecar's Avatar
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    Also, extremely important, when tuning gasoline, pay extremely close attention to knock/detonation, do everything to prevent it.

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    found a KPA absolute to inHg/psig chart that will help.. converted tables to G/sec
    stuff is starting to click now...
    do a working example.... engine I have is a 454 with 0411 ecm swap
    displacement x rpm, divide by 3456 = CFM
    CFM x 0.069=lb/mm
    lb/mm x 7.559= G/sec
    then multiply by engine efficiency..

    454*800rpm/3456=105.09 cfm
    105.09cfm * .069=7.25 lb/mm
    7.25lb/mm *7.559= 54.81 g/sec
    54.81g/sec divide by 8 cylinders is 6.85 g/sec per cylinder at 100%

    at 4400 rpm
    578cfm
    39.8 lb/mm
    301.47 G/sec
    37.68 G/per cylinder

    B0101 is closest with grams a second and VE accounted for.. at roughly 70-75%..VE

    when under edit->properties->display.. going from G/sec to G/cylinder..
    on square 4400 rpm/80kpa kPA
    G/sec the value is 204.9606
    G/cylinder the value is .7474
    how did they get .7474 from 204.9606?

    B5932 base spark is only coming up as gram cylinder
    while timing and lean AFR are best for HP/efficiency too much timing or too lean and they can kill hard parts fast

  7. #7
    Joe (Moderator) joecar's Avatar
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    Hi mal,

    In tunetool, go Edit->Configure Display Units and set everything to Metric.

    For gasoline engines, do not use CFM, use g/s (do you know what your engine's volumetric efficiency is...?).

    Look at B0101 using units g*K/kPa... GM already measured cylinder airmass and normalized it for pressure and temperature.

  8. #8
    Joe (Moderator) joecar's Avatar
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    Quote Originally Posted by malibu795 View Post
    . . .
    G/sec the value is 204.9606
    G/cylinder the value is .7474
    how did they get .7474 from 204.9606?
    204 is g/s, 0.747 is g/cyl.

    B5932 base spark is only coming up as gram cylinder
    while timing and lean AFR are best for HP/efficiency too much timing or too lean and they can kill hard parts fast
    Yes, correct, at significant load, must pay attention to timing (LS engine: 26 deg maxand you at 6000 rpm at WOT) and fueling (NA requires minimum EQR 1.175 at same conditions)... and you have to check for knock and adjust (decrease timing, increase EQR, increase octane) if it occurs.
    Last edited by joecar; November 11th, 2018 at 01:33 PM.

  9. #9
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    I'm dumbing timing tables down until I get a handle on it.. mimicking the timing plot off my carb'd and go from there
    The Gen 6 454s probably need more time I push 36

  10. #10
    Joe (Moderator) joecar's Avatar
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    SBC and BBC can run more timing than LS engine (LS head design promotes faster burn).

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