Is my fuel pump too big???

Discussion in 'PSI Superchargers Tech Questions' started by KennyKeller, Oct 21, 2009.

  1. KennyKeller

    KennyKeller New Member

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    526 aires, 14 degree heads Pro Mod Camaro, lenco drive K11 superman Enderle 1200 pump. We've done the math and it seems a little too much.
    Mike' I pm'd you about this but did not get a responce.
     
    #1
    KennyKeller, Oct 21, 2009
  2. shawn davis

    shawn davis Member

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    Put a decent sized pump loop and run it
    I pm some info to you
     
    #2
    Last edited: Oct 21, 2009
    shawn davis, Oct 21, 2009
  3. SoDak

    SoDak Active Member

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    k11 and I'm assuming its a 14-71?

    Too big a pump is alot better than too small:eek:

    How fast is the blower spinning?
     
    #3
    SoDak, Oct 21, 2009
  4. AnimalCrew

    AnimalCrew New Member

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    We are running a 526 KB Olds, Big Chiefs with a K11. It will make 51 lbs of boost in the 1/4 at 44 over. If we get into some Mine Shaft air the 1100 we are running may be too small so the answer is.... NO the 1200 is fine. As mentioned, put a loop in the system and use that to size the pump.

    Troy.
     
    #4
    AnimalCrew, Oct 21, 2009
  5. Greg Kelley

    Greg Kelley Member

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    Could someone explain what the "loop" deal is and how it works?
     
    #5
    Greg Kelley, Oct 21, 2009
  6. SoDak

    SoDak Active Member

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    A pump sizer/loop is where a check valve is set at some lower psi and returns fuel from the pressure side of the pump back to the inlet side of the pump. Most of the time (since it turns on at a low RPM), fuel is "looped" around the pump, making it act like a smaller pump, thus the other name "pump sizer".

    Hope this makes sense:)

    A check valve can be used for idle control (idle check), pump loop, high speed or pump saver. Essentially they are all the same housing but they're turned on at different psi's. I listed them from lowest psi to the highest.

    There are books available from Bob if you are interested in reading/learning.

    Here is a pic of a pump loop plumbed in a real common way. http://www.goodvibesracing.com/Product-Scans/E-80AHS6.JPG
     
    #6
    Last edited: Oct 21, 2009
    SoDak, Oct 21, 2009
  7. Mike Canter

    Mike Canter Top Dragster
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    The Pump Sizer Loop can be considered an extension of the Main Jet Circuit since it runs parallel to the main jet. Basically it is a poppet and jet holder that is screwed into a threaded hole on the fuel shutoff block that is ontop of the fuel pump and this either runs down to the inlet of the pump or back to the tank. Back to the tank is the prefered way. What I do is try and keep the Main Jets sizes within a certain range like 90 to 110 and if I can't because the DA gets too high then I put a 40-100 bypass jet in the pump loop to return fuel so my main jet comes back down in size. Normally you set the poppet at 35 to 40 lbs crack pressure. You would also need a blank off jet so if you get down to zero feet DA and needs lots of fuel you can blank it off.

    A pump sizer lets you run a larger pump and bypass the fuel you don't need. I have seen some cars that run two pump sizers.

    To compute the jet needed in the pump sizer you have to work with the area of the jet so if you need a 140 main jet then compute the area and subtract the area of a 90 jet then see what size pump sizer jet you need for that difference.
     
    #7
    Mike Canter, Oct 21, 2009
  8. Greg Kelley

    Greg Kelley Member

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    got it - thanks
     
    #8
    Greg Kelley, Oct 21, 2009
  9. secondwindracing

    secondwindracing top alcohol

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    we run a 526 with bae heads hi helix retro 50% over with 19.5 gal per min with no pump sizer we do run a 4 stage fuel timers..Dave
     
    #9
    secondwindracing, Oct 21, 2009
  10. KennyKeller

    KennyKeller New Member

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    Thanks guys
     
    #10
    KennyKeller, Oct 22, 2009
  11. Mike Canter

    Mike Canter Top Dragster
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    The size pump and the need for a pump loop also depends on where you race as what the average Density Alitude is out in the West the DA is always up around 4000 ft so you need less fuel. If your pump is too big then one of the solutions is to get a 10% underdrive which also reduces the chance of cavitation. The big headache with too big or too small of a pump is getting and maintaining the correct fuel pressure at the nozzle.
     
    #11
    Mike Canter, Oct 22, 2009
  12. bruce mullins

    bruce mullins Top Dragster

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    let me get this right, a roots combo and you feel you will need more than 17 gallons a minute?
     
    #12
    bruce mullins, Oct 22, 2009

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