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Aftermarket Fuel pump option....

Discussion in 'The Garage' started by Batmanjr, Oct 27, 2003.

  1. Batmanjr

    Batmanjr 1/2 ton status

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    First, I would like to know if anyone KNOWS the exact amount of PSI the stock electric fuel pump puts out on an 87+ newer truck?

    Second, I would like to mount a frame mounted fuel pump on my 87 Blazer with a Holley 670 CFM TBI. Holley's fuel pumps put out a range of 6-15 PSI with 97-250 gph... One puts out 45 PSI with 67 gph and is used on MPFI systems....

    I did some research and found two aftermarket pumps that are very reasonable in price and almost the same.... Here are the specs:
    1st: 18 PSI 100 GPH and it's a diaphram pump
    2nd: 20 PSI 50 GPH and it's a rotary pump

    Any suggestions of which one to get? Which is more important GPH, or PSI? And WHY? Thanks in advance! /forums/images/graemlins/thumb.gif
     
  2. wrathORC

    wrathORC 1/2 ton status

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    The "range" is 9-13psi. Most "new" pumps are in the 12-13psi range. At 9psi the vehicle runs pretty poorly at high temperatures. At 7psi it won't barely run.

    Ford has a bunch of different fuel pumps all under $100 with different fuel pressure and flow rates. If you search the 'net you'll find them.

    Diaphragm pumps tend to pulse and I don't like that. I'd much rather have a vane-type pump like my Carter street/strip pump (7psi) which doesn't pulse.

    A 355 at 6500rpm with 85% volumetric efficiency at 12.8:1 air/fuel ratio uses 33gph. More important than how much fuel it can flow is how fast it reacts to fuel demands. IE: When that motor says it wants to go from 1800rpm to 6500rpm and the computer dumps extra fuel down the throttle body that fuel pump had better be able to provide that pressure at that flow RIGHT then.
     
  3. Hossbaby50

    Hossbaby50 3/4 ton status

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    I just ordered the MSD EFI pump for my TPI conversion. It puts out 43 GPH at 40 PSI. It has a max continuous output of 55 PSI. The best part about it is it only runs about $80. I will see the product first hand Friday when it comes in. It puts out more PSI then you need, but if you get a regulator then you should be ok.

    There are alot of pumps out there that should be able to put out the 15 PSI or whatever your TBI needs. It is alot harder to find a pump for TPI.
     
  4. Batmanjr

    Batmanjr 1/2 ton status

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    I just found the stock pump stats:
    7 PSI with 38 GPH and of course its diaphram...

    So in other words, either would work....
    Why do people(not here so far) push Holley fuel pumps? They are diaphram too and anything over what the ragulator uses will be loss! Right? In other words, at least have some PSI to spare, and as much GPH in free flow as you can! Right! /forums/images/graemlins/ears.gif
     
  5. DieselDan

    DieselDan 1/2 ton status

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    Check this guy out. http://www.autoperformanceengineering.com/

    I bought my high pressure Walbro pump from him. /forums/images/graemlins/thumb.gif He got the lower PSI units (6000 series)too /forums/images/graemlins/deal.gif
     

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