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Thread: High Pressure Pump Start Angle table with aftermarket fuel pump lobes?

  1. #1
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    High Pressure Pump Start Angle table with aftermarket fuel pump lobes?

    When using a cam with an oversize fuel pump lobe are people adjusting the fuel pump start angle table? Seems like if I understand how things work it would take less start angle when the stroke is increased by an oversized fuel pump lobe.

  2. #2
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    I believe you edit the row axis on the leading edge angle. Multiply whatever percent fuel lobe you have to the entire row. This will edit both leading and trailing edge angles.
    2016 Silverado CCSB L83/6l80e
    TSP cam 218/226, .635"/.635", 113 LSA 10% FL
    TSP LT headers
    Stock converter

  3. #3
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    Quote Originally Posted by SILV View Post
    I believe you edit the row axis on the leading edge angle. Multiply whatever percent fuel lobe you have to the entire row. This will edit both leading and trailing edge angles.
    Could you share a little more about the leading edge angle? I'm not seeing it anywhere in the tune.

  4. #4
    Senior Tuner Ben Charles's Avatar
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    Under fuel system tab

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  5. #5
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    This is the table I am talking about. It seems to me that the table would need some sort of update based on a factor related to the fuel pump lobe. I don't see much in the scanner related to the pump control though.

    start angle table.png

  6. #6
    Senior Tuner Ben Charles's Avatar
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    That tables does need to be calibrated for larger cam lobe, info came from an OEM calibrator to do so

    Email Tunes, PM me for more info
    96 TA Blown/Stroked, 4L80E/Fab 9
    15 C7 A8 H/C 2.3 Blower/PI
    14 Gen 5 Viper
    Custom Mid Engine chassis, AKA GalBen C

  7. #7
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    Quote Originally Posted by DanLeeWatson View Post
    This is the table I am talking about. It seems to me that the table would need some sort of update based on a factor related to the fuel pump lobe. I don't see much in the scanner related to the pump control though.

    start angle table.png
    Yes that's the table. I dont know your application but it looks like the row has already been modified.
    2016 Silverado CCSB L83/6l80e
    TSP cam 218/226, .635"/.635", 113 LSA 10% FL
    TSP LT headers
    Stock converter

  8. #8
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    Quote Originally Posted by Ben Charles View Post
    That tables does need to be calibrated for larger cam lobe, info came from an OEM calibrator to do so
    So how do I go about doing that with HPTuners? I don't see much in the way of pump channels in the scanner.

  9. #9
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    You just update/edit the row axis values to reflect the percentage of increase in the pump’s output volume.
    Click on the row axis title to edit it.

  10. #10
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    Quote Originally Posted by crankz1 View Post
    You just update/edit the row axis values to reflect the percentage of increase in the pump’s output volume.
    Click on the row axis title to edit it.
    How are you determining the pumps new output volume? are you just assuming it is the same as the % called out on the fuel pump lobe?

  11. #11
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    Yes. Like SILV said above.

  12. #12
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    Quote Originally Posted by crankz1 View Post
    Yes. Like SILV said above.
    Ok, but how are people verifying this actually works properly? I can't find anything in the scanner that shows error or correction for pump pressure. I would think this table is the primary means to correct under and overshoot in the rail pressure but I never see it talked about.

  13. #13
    When I put in my 32% fuel lobe I never really noticed many fuel pressure issues, it appeared the commanded and desired behaved like stock. Anyway I multiplied the entire row axis by my new fuel lobe cam value (1.32) like SLIV said. I didn't notice any difference though but I feel better that its now "fixed" at least.