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  1. #1
    Super Moderator dave w's Avatar
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    1227747 $42 VE1 + VE2 Fuel Tables

    The screen shots below show how to add the '7747 VE1 + VE2 tables.

    It's my understanding that once the '7747 ECM goes above 3200 RPM's, the ECM will use the last known VE value from the 3200 RPM table. Typically, the 3200 RPM VE values are at or above 90's ( VE1 + VE2). It's very likely an engine operated by a '7747 at or above 3200 RPM's will already be above 80 Kpa.

    With the correct BPW the ideal VE1 + VE2 table will have low numbers in the low 40's and the high numbers will be no higher than the mid 90's.

    Use at your own risk.

    dave w
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    Last edited by dave w; 07-11-2012 at 07:27 AM.

  2. #2
    Fuel Injected! CDeeZ's Avatar
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    Thanks for posting this dave.

    This makes a lot more sense than jockeying two separate tables.

    After adding them, do you slew the table down at all before logging BLMs, so the VEs are not over 100??
    Last edited by CDeeZ; 07-11-2012 at 08:10 AM.

  3. #3
    Super Moderator dave w's Avatar
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    I only adjust VE1, even on a stock .bin file that will be using both VE1 and VE2.

    For VE cells over 100, I adjust to 96 and increase the BPW slightly ( usually 3 or less).

    I'll add VE1 + VE2 for modified engines (cams, heads, pistons, intakes, ect). For a stock or nearly stock engine, adjustments to BPW and VE1 are all that is usually required.

    dave w

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    RIP EagleMark's Avatar
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    Quote Originally Posted by CDeeZ View Post
    Thanks for posting this dave.

    This makes a lot more sense than jockeying two separate tables.

    After adding them, do you slew the table down at all before logging BLMs, so the VEs are not over 100??
    You have no choice in TunerPro, it will do it for you.

    I've read some other srticles on this and says to leave VE2 adder alone after 3200. This does not work. I've verified Daves way with a Wide Band O2 sensor and it works fine.

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
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    RIP EagleMark's Avatar
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    Dave I found a better way to add to BPW/BPC in these, add to injector bias.

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
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  6. #6
    Fuel Injected! CDeeZ's Avatar
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    Quote Originally Posted by EagleMark View Post
    You have no choice in TunerPro, it will do it for you.
    I know that TPRT caps the VE values at 100 or 99.6 or whatever it is.




    I must say, configuring the VE tables using daves method of VE1+VE2 has given me better results than anything else I've tried as far as messing with the fuel tables in the 747.

    I added my VE tables together using daves method, then slewed the whole table down a few points so that no VEs were over 100, or close to for that matter. I've done several logs and adjusted the fuel table down and now, my highest is like 88 and lowest is like 22. This is after a few BLM adjustments using daves VE calc spreadsheet

    Mark I think you told me lower is better regarding VEs, correct? (within reason of course)

    I haven't checked BLM since doing the last adjustment but I expect them to be +/-3 in most areas..

    dave, you said ideally the lowest VE should be low 40s and highest mid 90s. Really anywhere is OK though as long as you're not maxed out to either extreme 0 or 100 right? I used yet another handy tool of yours, the BPW spreadsheet you created, and came up with my BPW, dropped it into the tune, combined VEs, slewed main VE down a bit and proceeded to collect BLMs. After a few BLM logging sessions my lowest VE is now ~22 and highest VE ~88.
    Last edited by CDeeZ; 07-13-2012 at 06:25 AM.

  7. #7
    RIP EagleMark's Avatar
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    Quote Originally Posted by CDeeZ View Post

    Mark I think you told me lower is better regarding VEs, correct? (within reason of course)
    No that was not me nor is it correct, VE Volumetric Efficiency has to be correct weather low or high. Just can not exceed 95 in highest cell and lower is better.


    Quote Originally Posted by CDeeZ View Post
    I haven't checked BLM since doing the last adjustment but I expect them to be +/-3 in most areas..
    Can't get much better then that, even if you did it would change with weather.

    The reason Dave W BLM Spreadsheet works so well with this method is it's adjusting 100% of the value, what it is designed to do. If you still had VE2 then... lets say VE2 had 39% rounded to 40% for simplicity. Then you applied the spreadsheet calculations to VE1 which is the other 60%, so you have adjusted 60% of total VE not 100%.

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
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    RIP EagleMark's Avatar
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    Since Dave brought this up and seems to be of intrest I'll give some calibration theory taking from some of the best calibrators/tuners.

    First adding VE2 to VE1 fueling table is usually easy and only one number, (Refer to Dave W first post) for instance ADSU is 39.06 for the entire VE1 table, use the Offset +/- tool in TunerPro and add it in, zero out VE2 and save bin with new name protecting your starting bin. This is what you end up with.

    Stock with VE1 and VE2 added together.


    1227747 $42 does not have a big resolution of table compared to later masks with say double the amount of cells. Tuning basics says to start with a smooth table, open your wireframe veiw and do some manual smoothing to make the table look more consise, then use the smooth tool to finish it off one cell at a time or row by row, setting it to .10 is a huge smooth and .90 is a small adjustment, I use .5 so it ends up something like this below.

    So where do you start? Well if you look at the table, not wire frame, basically leave all four corners alone. Max number in bottom right should be no higher then 95 max, lower is better if you have big enough injectors and fuel pressure to support engine HP.

    After smooth.


    Reason for this is the way the ECM/PCM get's it's VE number for a given cell, say your using data tracing or the engien is running in this cell.


    Well the ECM/PCM does not use that cell alone! It is a calculation of that cell plus four surrounding cells.


    With that you can understand how and why it's easier and more accurate let alone easier for the ECM, in this case a slow ECM to make adjustments to fuel as needed.

    In the end of tuning and making adjustments via BLM readings and a spreadsheet the final tune would look something like this.
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    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

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