Walbro 255lph fuel pump?

Discussion in '94-95 5.0 - Specific' started by EVOIX, Jun 27, 2007.

  1. EVOIX

    EVOIX New Member

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    Is it ok to put a Walbro 255lph fuel pump on this SN95 (with a BBK FPR):
    Mustang GT 95
    Mods:
    C&L 76mm intake kit
    Cobra Upper and Lower intake
    BBK shorty headers
    BBK 70mm TB
    Flowmasters catback
    Highflow cats / midpipe

    I want to go with a 255 so I don't have to upgrade later
     
  2. Paul

    Paul Legend

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    Yes.
     
  3. Schiffy

    Schiffy Well-Known Member

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    Yes, but why so big? do you have big plans? I personally am going to go with an exterior fuel pump when it's that time in my buildup.
     
  4. 95KBGT

    95KBGT Legend

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    yes, but your prob not going to need it till you add a power adder. plus your going to run rich and bad gas milage. in my blown 95 i went from 13MPG to 7MPG
     
  5. quickstang_1994

    quickstang_1994 Well-Known Member

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    Yeah, You don't want to do things twice. The computer will compinsate for the fuel(it's not a returnless system). But I would take off the regulator and let the computer do its job. If you may supercharge in the future you may want a high pressure.
     
  6. EVOIX

    EVOIX New Member

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    Wanted to go with a 255 just in case. O0 The stock fuel pump in the car seems to not be delivering enough fuel or there is some problem with the stock regulator so thats why we are putting on a new pump and regulator. When you are driving then stop the car, turn it off, and restart it. It has lots of power for a few pulls then bogs down. We tried taking the vacuum off the regulator and it ran a whole lot better (even with all the fuel at low rpms). The fuel gauge shows 40 (with vacuum disconnected) and 32ish (with it connected). Once I get my new/broken LC-1 back from Innovate I will try to get some A/F readings.
     
  7. SonicStang

    SonicStang Active Member

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    ??? I thought the comp. manages how much fuel is going to be burned, the rest goes back into the fuel cell (return style fuel system)...
     
  8. ryclef331

    ryclef331 Well-Known Member

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    Alright...class in session.

    The fuel pressure regulator adjust fuel pressure SOLELY BASED on its vaccum signal. THATS IT. With NO VACCUM (either unhooked OR at WOT), it will allow the max fuel pressure it can (whatever you set it at or factory...depending on regulator used). The pump flows at a constant VOLUME....restricting the flow of the volume increases pressure (this is what the regulator does by opening or closeing the internal orifice of the return port). The computer has NOTHING TO DO with the regulator at all. NOTHING.

    The computer controls the timing or and how long the fuel injectors stay open (pulse width). It does this based on reading from the O2s, RPM, IAT, MAF and Throttle Position. All those readings are calculated to figure out how long it should open for.

    Now YES, increasing your fuel pressure will fatten up the mix but then the computer CAN reverse that effect by decreasing pulse width....in theory. Its not a perfect world and it doesn't always work that way.

    Generally on a stock car by bumping timing and leaning the fuel pressure back a few lbs, you can pick up 5-10hp....plus better economy. What fuel pressure works best varies from car to car. Find what works best for you.

    Class dismissed.
     
  9. EVOIX

    EVOIX New Member

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    Thanks ryclef331.

    {off topic} Now when you boost your max fuel pressue is no longer at vacuum its at max boost. This is why on a turbo cars you should never tap a boost gauge off your fuel pressure regular. You don't want any leaks or the line falling off the FPR on a turbo car lol

    Now back to this mustang. Anyone know why when I restart the car after it has been running why it has lots of power then after a couple pulls its bogs down till then next time I restart it? Also why it has lots of more power with the FPR vacuum off - constant 40psi (max psi on this stock regulator)?

    Any help on this whould be great. I going to do the fuel pump, then the regulator, but I was just wondering why it car would seem to need more fuel.
     
  10. SonicStang

    SonicStang Active Member

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    Okay. But if you still have the 19 pound injectors there won't be that much of a difference, right?
     
  11. ryclef331

    ryclef331 Well-Known Member

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    yes it makes a difference on 19's. Try changing out your plugs and fuel filter as well..
     
  12. EVOIX

    EVOIX New Member

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    I put the fuel pump and fpr in. It has a new fuel filter. It seems to run good at 50psi with the vacuume off (about 42psi with vac). Any lower it bogs.

    The plugs are not that old but I will check them.
     
  13. purplehaze

    purplehaze Member

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    hey everyone! ;D i finally found this topic on fuel pumps and wanted some advice as to if i can switch out my fuel pump or fuel regulator in my 95 gt.
    my mods are:
    cold air intake
    70mm tb
    trick flow street upper and lower intake
    e303 cam
    bbk pullys
    bbk long tube headers
    o/r h-pipe w/ dynomax bullets
    3.73 gears
    stock 19lb injectors
    wanted to upgrade my fuel pump and regulator but dont know if it will affect my car.can anyone give me a size of pump i should go with?can i use an inline pump, oh i plan to start using nitrous within the next month or so!thanks for your time guys.