fuel management plumbing

Discussion in 'PSI Superchargers Tech Questions' started by overkill69, Sep 3, 2011.

  1. overkill69

    overkill69 Member

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    I'm installing a 4 stage management block on a screw fuel system. One stage will be for the 2 step and the others will work downtrack.
    My Waterman pump has a nice -8 fitting just below the shutoff valve. Is that a good place to pull fuel to the mangmt. block?

    thanks
    Mike
     
    #1
    overkill69, Sep 3, 2011
  2. Don Onimus

    Don Onimus New Member

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    fuel mang.

    You are not suppose to take fuel away on a screw blower down track. Forget all you did or heard about a roots. If it is a auto, you keep it fat off the line. If it is a stick, you lean it out off the line then put it back in. along with the timing. That port can be used for a pump sizer. Just a thought. Don
     
    #2
    Don Onimus, Sep 4, 2011
  3. rb0804

    rb0804 Active Member

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    You can take it off of the -8 on the pump, this is where I take mine from. It has less of an effect then if you were to take it from the back side of the barrel valve, but it doesn't really matter. In general, you only need a low gear leanout with the PSI to get it thundering and you run out the back half on the main.
     
    #3
    rb0804, Sep 5, 2011
  4. overkill69

    overkill69 Member

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    psi

    Thanks. I'm rich on the hit and getting a little lean downtrack. I needed a leanout for the two step and couldn't really get anybody to vouch for the lowgear leanout on a 1/8th mile two speed car so i'll do it all with the mangmt. block.
     
    #4
    overkill69, Sep 5, 2011
  5. ibaddlizzard@aol.com

    ibaddlizzard@aol.com New Member

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    why you want to lean it on the 2 step ?
    Doc
     
    #5
    ibaddlizzard@aol.com, Sep 5, 2011
  6. overkill69

    overkill69 Member

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    everybody else does..lol. We run a airthrottle so it doesn't leave with huge boost and has been dropping cylinders intermittently.
    It also beats up headers terribly.
    I think it would run on a good track but we are running really weak tuneups with a LOT of timing out...it tends to be a rich pig on the bottom.
     
    #6
    overkill69, Sep 5, 2011
  7. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    fuel down track

    Don,

    If you are running your fuel system dead nuts on the main jet the entire run on the 1/4 mile, then it's not a good thing to pull fuel out down track that you aren't going to put back in.

    If you are running a converter car with a C rotor, or D for that matter, it's not uncommon for someone to run the car overly rich early to get it off the line, then bleed fuel off with management to get the fuel back to the correct amount. Also, you can run leaner to the 1/8 mile than you can the 1/4. So let's say your combo takes 14 gallons on the davenport. Maybe you leave with 15 gallons and open a 60 jet at 1.5 to bring the flow back to 14 gallons. That would take the 'edge' off a converter car prone to smoke the tires.

    In reference to the plumbing question, if you are leaving at part throttle - if you plumb your management off the pump, it will kick in at stage if you have Normally Open solenoids. If you plumb it off the return side of the BV, Normally Opens will not be as noticeable at stage rpm. It doesn't really matter where you plumb it if you are leaving WOT.

    Also if you have Normally Open circuits, it's not a bad idea to put the circuit on a check a little higher than your idle check to prevent them from flowing at idle and making your head temp too hot.
     
    #7
    Will Hanna, Sep 6, 2011
  8. overkill69

    overkill69 Member

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    plumbing

    Will, I have normally closed solenoids. The transbrake will activate one for the two step/stage. The others will go off a timer triggered by transbrake release. I assume it might act stupid after the burnout when the driver uses the transbrake to shift the reverser.

    This is a D rotor chevy car launching at part throttle.

    Thanks ITA
     
    #8
    overkill69, Sep 6, 2011
  9. rb0804

    rb0804 Active Member

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    You could either install a switch on between the transbrake button and what ever you are using to trigger the fuel management, or you could wire (or plumb if you are using air) off of a switch on the throttle pedal, that way you have to be full throttle AND be on the transbrake for it to activate the fuel management.
     
    #9
    rb0804, Sep 6, 2011
  10. blownapex

    blownapex Member

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    fuel managementl

    make sure you use a wot switch with the trans brake switch
    so its only activated wot when the tb is released
    ill have to look but i think i used a relay
    look at lehees diagrahm for a clutch/ wot
    duane
     
    #10
    blownapex, Sep 6, 2011

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