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Thread: Correct IFR tables for LS3/LS7 injectors in Gen III

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    Default Correct IFR tables for LS3/LS7 injectors in Gen III

    I have an 04 Silverado PCM and Ive swapped LS3 heads, intake, and injectors on my 6.0L (LQ9).

    Ive been doing some AutoVE tuning just to get the hang of things. Ive got that down and my LTFT are 0-3% almost all the time.

    Now I want to stop practicing and do it right, Ive read that its best to use a GM injector because GM did all the work with ALL the other setting besides flow rate. So I chose a stock injector specifically for that reason. I thought it would just be a "copy and paste" all of the tables, but they do not line up at all and some tables just dont exist. Im assuming its since the LS3 and LS7 cars use a different PCM.

    How do I make sure my IFR tables are correct? Ive found stock tunes for LS3 and LS7 Vettes on holdencrazy but dont have the knowledge to swap/convert everything.
    Last edited by joecar; October 18th, 2009 at 05:59 AM. Reason: Fixed title spelling...

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    I used the spreadsheet I found on here to get my numbers in my tune. I just told the spreadsheet I had 41lb/hr injectors and copied and pasted the table.
    Last edited by SweetS10V8; August 2nd, 2009 at 01:10 AM.

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    EFILive Distributor dfe1's Avatar
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    Quote Originally Posted by SweetS10V8 View Post
    I have an 04 Silverado PCM and Ive swapped LS3 heads, intake, and injectors on my 6.0L (LQ9).

    How do I make sure my IFR tables are correct? Ive found stock tunes for LS3 and LS7 Vettes on holdencrazy but dont have the knowledge to swap/convert everything.
    The LS3/LS7 injectors are flow rated at 4-bar, the same as LS1/LS2 injectors. All you need to do is use the values in a file from a vehicle that uses the injectors you've selected. Couple of suggestions-- make sure the flow units are the same in both files-- either Imperial or metric, keep in mid that the IFR tables in Gen4 ECMs are referenced to "Delta MAP"-- the difference between Manifold Absolute Pressure (MAP) and fuel rail pressure. and-modified fuel system pressure. A Delta MAP of 400 kPa equates to 4bar of fuel pressure and 0 manifold vacuum so the value at 400kPa in a Gen4 file equate to the value at 0 in a Gen3 file. Note the flow rate table in both files is B4001.
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    Quote Originally Posted by dfe1 View Post
    All you need to do is use the values in a file from a vehicle that uses the injectors you've selected.
    That was the plan until nothing matched up. Thats why I posted the differences under my injector folders in my tune ('04 Silverado) and the stock tune ('08 Vette) which has the exact injectors Im using.
    Quote Originally Posted by dfe1 View Post
    keep in mid that the IFR tables in Gen4 ECMs are referenced to "Delta MAP"-- the difference between Manifold Absolute Pressure (MAP) and fuel rail pressure. and-modified fuel system pressure. A Delta MAP of 400 kPa equates to 4bar of fuel pressure and 0 manifold vacuum so the value at 400kPa in a Gen4 file equate to the value at 0 in a Gen3 file. Note the flow rate table in both files is B4001.
    So i400kpa in gen IV = 0 in gen III? Thats great, but the helps me fill in one single input. How do I convert the rest?

    What about the rest of my inputs under my injector file that dont line up with anyhting from the tune that uses the injectors Im running?

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    Quote Originally Posted by SweetS10V8 View Post
    That was the plan until nothing matched up. Thats why I posted the differences under my injector folders in my tune ('04 Silverado) and the stock tune ('08 Vette) which has the exact injectors Im using.
    So i400kpa in gen IV = 0 in gen III? Thats great, but the helps me fill in one single input. How do I convert the rest?

    What about the rest of my inputs under my injector file that dont line up with anyhting from the tune that uses the injectors Im running?
    Ive just done this


    http://forum.efilive.com/showthread.php?t=11878

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    Joe (Moderator) joecar's Avatar
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    Expanding on what dfe1 said:

    GenIII:

    pressure difference across injector = FP + MANVAC
    so then: IFR = R0 * sqrt((FP + MANVAC) / P0)
    where: FP = fuel rail pressure = 58 psi = 4 bar = 400 kPa

    GenIV:
    pressure difference across injector = DELTAMAP
    so then: IFR = R0 * sqrt(DELTAMAP / P0)
    This is what Gelf did using the spreadsheet.


    Last edited by joecar; November 13th, 2009 at 10:53 AM. Reason: Added missing parenthesis...

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    EFILive Distributor dfe1's Avatar
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    Quote Originally Posted by SweetS10V8 View Post
    That was the plan until nothing matched up. Thats why I posted the differences under my injector folders in my tune ('04 Silverado) and the stock tune ('08 Vette) which has the exact injectors Im using.
    Things aren't going to match up exactly because, among other things, the voltage offsets are different between LS1 and LS3/LS7 style injectors. Don't worry about every number being exactly what you think it should. There are a number of factors that come into play, not the least of which is that even in a bone stock LS3 or LS7, the fuel trims are likely to be off a good bit. I can't remember the last time I saw a stock tune with long term trims that were consistently in the 0 to -5% range.
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    Joe (Moderator) joecar's Avatar
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    Quote Originally Posted by joecar View Post
    Expanding on what dfe1 said:

    GenIII:
    pressure difference across injector = FP + MANVAC
    so then: IFR = R0 * sqrt((FP + MANVAC) / P0)
    where: FP = fuel rail pressure = 58 psi = 4 bar = 400 kPa

    GenIV:
    pressure difference across injector = DELTAMAP
    so then: IFR = R0 * sqrt(DELTAMAP / P0)
    This is what Gelf did using the spreadsheet.


    So it seems that DELTAMAP is the same as FP + MANVAC... they are both the pressure difference across any one injector.

    This can be used to convert the vertical axises between the GenIV and GenIII B4001 tables...

    OEM stock value of FP is 4 bar (58 psi, 400kPa):

    Code:
      MANVAC  MANVAC+FP
      [kPa]    [kPa]
        0       400 <--- WOT
       10       410
       20       420
       30       430
       40       440
       50       450
       60       460 
       70       470 <--- idle (small cam)
       80       480

    I need a sanity check, does that make any sense...?


    So, in other words:
    the GenIV B4001 cells between DELTAMAP 400 and 480 [kPa] correspond to
    the GenIII B4001 cells between MANVAC 0 and 80 [kPa].


    See the highlighted cells in the attached ZR1/LS9 B4001 table.


    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	ZR1--LS9--B4001.png 
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    Last edited by joecar; November 13th, 2009 at 01:03 PM.

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    Joe (Moderator) joecar's Avatar
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    Same with GenIV B1210 --> GenIII B3701... copy the slice ranging 400-480 kPa, and interpolate between missing cells.

    The other injector tables can be matched up by their name and/or description.

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    Quote Originally Posted by joecar View Post
    So it seems that DELTAMAP is the same as FP + MANVAC... they are both the pressure difference across any one injector.

    This can be used to convert the vertical axises between the GenIV and GenIII B4001 tables...

    OEM stock value of FP is 4 bar (58 psi, 400kPa):

    Code:
      MANVAC  MANVAC+FP
      [kPa]    [kPa]
        0       400 <--- WOT
       10       410
       20       420
       30       430
       40       440
       50       450
       60       460 
       70       470 <--- idle (small cam)
       80       480
    [FONT=Courier New]
    I need a sanity check, does that make any sense...?

    Consider yourself sane. lol.
    The Tremor at AIR

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