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Thread: 5psi on stock LT1 fuel system

  1. #1
    Advanced Tuner Ghostnotes's Avatar
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    5psi on stock LT1 fuel system

    I'm running stock bore/stroke with a YSi-V7. Stock bottom pulley with a 3.8 upper and at about 4500rpm i start getting above 5ms.

    Is this about right? I'm a few months away from my fuel upgrade. My HPFP pressure stays good in regards to commanded and actual but my LPFP starts to lag. There is no knock and it does not run lean. I top out at around 5psi boost total. I have not tried to make any adjustments to the fuel system yet because I'm not sure if it would actually help.

    Thanks.
    I always tune VVE....
    2016 C7 M7 Z51
    Callies ultra billet crank
    Callies ultra billet rods
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    Jhonson high speed lifters
    Ported and polished headwork
    Custom cam
    YSi-V7

  2. #2
    Senior Tuner Higgs Boson's Avatar
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    What PE are you commanding? If it is too rich you can get a little headroom running leaner, of course not too lean.

  3. #3
    Advanced Tuner Ghostnotes's Avatar
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    Quote Originally Posted by Higgs Boson View Post
    What PE are you commanding? If it is too rich you can get a little headroom running leaner, of course not too lean.
    I'm at 11.8 but i have read conflicting posts that says 12.5 is safe on DI as well.


    I've developed a little knock as well in the 3000rpm/80-90 airmass range, but i think i know what that is.It's hot as hell in Houston now and I think my timing is off now along with my PE enable pedal might be coming on too soon. It was great until the heat came on.
    Last edited by Ghostnotes; 06-07-2019 at 12:33 PM.
    I always tune VVE....
    2016 C7 M7 Z51
    Callies ultra billet crank
    Callies ultra billet rods
    Diamond pistons
    Jhonson high speed lifters
    Ported and polished headwork
    Custom cam
    YSi-V7

  4. #4
    Senior Tuner Higgs Boson's Avatar
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    Quote Originally Posted by Ghostnotes View Post
    I'm at 11.8 but i have read conflicting posts that says 12.5 is safe on DI as well.


    I've developed a little knock as well in the 3000rpm/80-90 airmass range, but i think i know what that is.It's hot as hell in Houston now and I think my timing is off now along with my PE enable pedal might be coming on too soon. It was great until the heat came on.
    11.8 on 14.1 stoich is the same as 12.3 on 14.68 stoich so....

    maybe use lambda instead. :-)

  5. #5
    Advanced Tuner Ghostnotes's Avatar
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    I get it but do think i read somewhere someone was running 12.5 on 14.1 stoich sounded off to me.
    I have adjusted my SOI but not in that area so that rules that out.

    I guess I am at my limit then.
    I always tune VVE....
    2016 C7 M7 Z51
    Callies ultra billet crank
    Callies ultra billet rods
    Diamond pistons
    Jhonson high speed lifters
    Ported and polished headwork
    Custom cam
    YSi-V7

  6. #6
    Senior Tuner SultanHassanMasTuning's Avatar
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    toss a boost a pump on your Lowside, but this is very low boost and the stock form should be sufficient
    Follow @MASTUNING visit www.mastuned.com
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  7. #7
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    Ghost maybe pay some for tune. - since u have so many problems.

  8. #8
    Advanced Tuner Ghostnotes's Avatar
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    Quote Originally Posted by paulsmithsr View Post
    Ghost maybe pay some for tune. - since u have so many problems.
    HUH?

    At this point I only have 2. One is lack of fuel which is fixable, the other is HPT does not seem to calculate coefficients correctly on some os's. The car runs great on MAF only. However if my MAF actually fails.....then I will have a problem.

    I have a lot of unanswered questions but i would not consider that a problem, just a hurdle.
    I always tune VVE....
    2016 C7 M7 Z51
    Callies ultra billet crank
    Callies ultra billet rods
    Diamond pistons
    Jhonson high speed lifters
    Ported and polished headwork
    Custom cam
    YSi-V7

  9. #9
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    Quote Originally Posted by Ghostnotes View Post
    HUH?

    At this point I only have 2. One is lack of fuel which is fixable, the other is HPT does not seem to calculate coefficients correctly on some os's. The car runs great on MAF only. However if my MAF actually fails.....then I will have a problem.

    I have a lot of unanswered questions but i would not consider that a problem, just a hurdle.
    He's just being a troll at this point, I'd ignore him.