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Thread: E38 and Power enrichment

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  1. #1
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    Default E38 and Power enrichment

    I have a 2008 5.3L E38 Silverado that was brought into me to tune, it has a homemade turbo install. Stock MAF, Injectors (i am sure they will be too small) the problem I am having is when I get the throttle to a point where I am getting into a few psi of boost I want the PE to kick in, I have lowered the TPS for PE and made sure there is no delay for Pe, yet the enrichment will still not come in until a much heavier throttle? Any help would be appreciated, it is a mild truck so the stock MAF should be ok?
    Mark

  2. #2
    Lifetime Member swingtan's Avatar
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    check this thread....

    http://forum.efilive.com/showthread.php?t=6461

    in some ( if not all ) E38 tunes, the PE TPS figures are not the same as the logged ETCTP PID. There can be a logarithmic relationsip that makes setting the PE via TP% a little more difficult. At post 7 in the above thread, I give a quick table for the corrections. This may be your issue.

    Simon

  3. #3
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    Thanks, that make sense I'll try it
    Mark

  4. #4
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    Default VVE Which ones

    Ok it worked great, one question about VVE and the differant ones, there are open intake valve closed intake valve.
    the truck has no intake valve
    one bar two bar three bar
    one and two bar make changes to the fueling but how do you know which it is in when? and should the higher vacuum area of the two bar be similar or the same in numbers as the one bar? what is the whole thing with the calculate co eficients or what ever it is called?
    should the vve look like a normal ve table?
    sorry about all the questions I have been reading as much as I can find in the forum.
    Mark

  5. #5
    Lifetime Member GAMEOVER's Avatar
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    Have you read Swingtan's tutorial on VVE adjustment:http://download.efilive.com/Tutorial...20Tutorial.pdf
    2008 2WD Ext.Cab Silverado 1500 6.0 V-MAX E38(L76) & T42(4L70E) MAF Only CL Corvette Servo AFE CAI INNOVATIVE LM-2 WBO2

    FLASHSCAN V2 & AUTOCAL

  6. #6
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    Yes a couple of times and it is great, I didn't see those answers in there I'll look again?
    Mark

  7. #7
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    It does answer what it should look like, and slightly about what generating coefic are, still not clear totaly why it is in there and not just a ve table? what about the diff vve tables how do you know which it is using since they all have high vac areas, and should the high vac areas be sam or similar to each other?
    Mark

  8. #8
    Joe (Moderator) joecar's Avatar
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    Quote Originally Posted by markemac View Post
    It does answer what it should look like, and slightly about what generating coefic are, still not clear totaly why it is in there and not just a ve table? what about the diff vve tables how do you know which it is using since they all have high vac areas, and should the high vac areas be sam or similar to each other?
    The E38 and E67 calibrations contain all those tables of polynomial coefficients, this is how the GM engineers designed the E38 and E67 to function...

    since humans can't visualize what the 3D VE graph looks like from a set of coefficients, the EFILive tunetool provides a tool which maps the coefficients to a 3D virtual graph... the tool lets you edit the graph from which it recalculates/regenerates the coefficients.


    Look at the name of the tables... the various tables apply for those situations... look at the descriptions of each of those tables... somewhere in the calibration are entry/exit parameters for the various modes.




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  9. #9
    Lifetime Member swingtan's Avatar
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    The way I "think" it works is....

    • Adjusting the 1Bar ( up to 105kPa ) VVE should suffice for non FI appliactions.
    • If going FI, then the 2Bar VVE will need to be adjusted. The lower pressure areas ( higher vacuum ) should take the shape of the 1Bar tune and you should only need to adjust the upper areas.
    • The Intake Valve / open tables only need to be changed if your vehicle has the vale fitted. I don;t have one so I just copy the 1Bar table for both open and closed.


    The reasoning behind this is that in reality, there is not multiple "tables" in the tune at all, just one set of coefficients. The tables were generated to help us visualise the shape of the graphs. So the 2Bar VVE is actually the 1Bar VVE with a set of higher pressure values stuck on the end.

    Of course, you could avoid a lot of this if you plan to keep the MAF and just set the high speed air flow setting to just off idle........

    Simon.

  10. #10
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    I really liked the bit on IAT adjustment correction, (havn't done this on a E38 yet) well done for taking the time to put this all down for others to benefit from mate. Bloody impressed !!!
    I'm doing a brand new E2 wagon R8 next week so I'll be giving that a go.



    Quote Originally Posted by GAMEOVER View Post
    Have you read Swingtan's tutorial on VVE adjustment:http://download.efilive.com/Tutorial...20Tutorial.pdf
    "Just a tune > yeah right !!!! "

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