2 step fuel bypass

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by Neil Morley, Jan 20, 2017.

  1. Neil Morley

    Neil Morley Member

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    Hey guys just put an electric solenoid on my car to bypass excess fuel when on the two step, not sure what size pill to start with I don't want to go to lean and hurt something when the BV is wide open while on the two step, it's a conventional headed 555ci BBC with a very good HH 14/71 will probably be OD it 39% it has an Enderle 990 pump (15.8 GPM) and will have the two step set at somewhere between 4000-4400 rpm . Any input is greatly appreciated, thank you!
     
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  2. Mike Canter

    Mike Canter Top Dragster

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    You didn't say if you had a fuel flow sensor. If you do you want about 5.7 to 5.9 GPM on the two step. Either with or without I would start with around a 60 jet.
     
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  3. Neil Morley

    Neil Morley Member

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    I don't have a fuel flow sensor but would like to add one soon but thank you mike.
     
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  4. TADHemiracer

    TADHemiracer Member

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    I have a poppet connected to the back of the hat D-block and plumbed it to a solenoid valve mounted on the side of the blower. I put a 30# spring in the poppet so that with the valve open, the hat always has a minimum of 30# fuel pressure and is still adjustable up and down of course. I don't even HAVE a pill in it.
     
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  5. Mike Canter

    Mike Canter Top Dragster

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    TADHemiracer, can you explain the theory behind that setup. Not sure I can tell what you are trying to do. Is this a TwoStep leanout? Why the poppet with a solenoid valve.
     
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  6. TADHemiracer

    TADHemiracer Member

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    Yes, a two step lean out. I am still trying to get a handle on my tune up and I find that the poppet with a set minimum pressure makes it easier for me to find the right amount of lean out without trying different pills. It works for me, may not be how the pros do it.
     
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  7. TADHemiracer

    TADHemiracer Member

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    Seems like the purpose of the pill is to limit how much fuel pressure is in the hat during twp step, the poppet does the same thing without depending on a pill being correct or a pump loop being correct or whatever.
     
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  8. Mike Canter

    Mike Canter Top Dragster

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    Nope the pill is bypassing fuel and not limiting pressure. It is just a main jet extension circuit while on the two step. With our MFI systems you are more interested in changing flow by changing orifice size.
     
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    Last edited: Jan 20, 2017
  9. TADHemiracer

    TADHemiracer Member

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    So, the pill does not limit fuel pressure while on the two step?
     
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  10. TADHemiracer

    TADHemiracer Member

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    And/or the lean out valve pill does not limit fuel pressure while on the two step???
     
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    Last edited: Jan 20, 2017
  11. TADHemiracer

    TADHemiracer Member

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    To me, bypassing fuel and/or limiting pressure is hand in hand. One goes with the other. Maybe it is just my stupid country boy "find a way to make it work" way of thinking.
     
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  12. Bob Alberty Jr.

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    Considering doing something like this myself.
    At .7 seconds (868 average egt, with .73 fuel flow, @1700 rpm) prior to the release of the brake, the throttle /barrel valve go to wot (delay box car).
    At the release (736 average egt, 5.80 fuel flow, @ 4000 rpm. ) for a 132 degree reduction of average egt.
     
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  13. Mike Canter

    Mike Canter Top Dragster

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    TAD, you are most interested in the GPM of fuel going into the motor. Once you have initially established the correct fuel pressure then it becomes secondary. You turn by how many GPM of fuel going into the motor
     
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  14. TADHemiracer

    TADHemiracer Member

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    As of now, I tune by what my motor is happy with and what the ET slips tell me. I have no flow meter and not going to invest in one. As I said, this is what works for me.
     
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  15. Aussiebattlr

    Aussiebattlr Member

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    D Rotor PSI With converter, what fuel flow should we have at idle?? (1800-2000) and at stage (3800-4300)??
     
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