Port Nozzel pressure

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by Brad671, Jul 28, 2008.

  1. Brad671

    Brad671 New Member

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    At what pressure do port nozzle typically come in at?
    And how would you determine what pressure they are coming in at?
     
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  2. td1506

    td1506 Member

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    our port nozzel poppett is set at 10 lbs.
     
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  3. SoDak

    SoDak Active Member

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    Ours comes on at 10 lbs also.
    How to check,,,
    take the poppet off and hook it up to a air pressure regulator and gage, turn up the regulator psi until it physically opens, now read your gage
     
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  4. jim phillips

    jim phillips ta/fc

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    my comes in at 12 lbs my tune up calls from 10 to 12 lbs you should be good at one of these settings
     
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  5. LeWhite

    LeWhite BB/Alt

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    Any benefit to drilling a .030 to .060 hole in the poppet?
     
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  6. MKR-588

    MKR-588 Member

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    With 10 to 12 lbs , wouldn't it be letting fuel in at idle?
     
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  7. secondwindracing

    secondwindracing top alcohol

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  8. Mike Canter

    Mike Canter Top Dragster

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    If you drill the poppet then surely you would change the pop point. Are you doing this so some small amount of fuel enters the port nozzles when the poppet is closed at idle?
     
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  9. SoDak

    SoDak Active Member

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    Mine is on at about 1800 RPM.
     
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  10. Brad671

    Brad671 New Member

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    So when I leak down the BV should air be coming out the port nozzels if the pressure is so low? Because on mine it doesn't.
     
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  11. Mike Canter

    Mike Canter Top Dragster

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    If you are leaking the barrel valve the hoses to the hat and ports should be disconnected from the barrel valve and the idle return should be capped off. Something tells me that if you are asking that question you are not leaking the BV correctly.
     
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  12. Brad671

    Brad671 New Member

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    Oops, so I have to disconnect the lines to the hat and port nozzels and leav them open or block them off?
     
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  13. Mike Canter

    Mike Canter Top Dragster

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    You leave those lines open
     
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  14. mbaker3

    mbaker3 New Member

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    I guess I have been doing this wrong too! I thought the only way I would know how much fuel was getting to the Hat nozzles was to "leak test" through barrel valve to the hat nozzles. What ever percentage that it comes to I can increase or decrease the amount with the barrel valve linkage.
    Without going through your hat nozzles, I didn't think it would be telling you anything useful.:confused:
     
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  15. WJ Birmingham

    WJ Birmingham New Member

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    Newp... Like Canter said...

    You cap the returns, and remove the hat/port connections.

    BV leak is ONLY the leak going past the spool at idle.
     
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  16. WJ Birmingham

    WJ Birmingham New Member

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    According to Wizbang, assistant tuner on Ron Smith's Top Fuel car, they are only running about 7 PSI at idle.

    According to our data logger, we're only running 1-2 PSI at idle. I would have to think a Pro-Mod or TA motor would lie somewhere in between.

    If the ports don't open until 10-12 psi (we use 15 psi), there's no way it would be unseating the poppet, unless the poppet is leaking.
     
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  17. 560Jim

    560Jim Member

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    I`ve been doing it with the hat and port lines hooked up as well. I`ve just gone and checked BV leak with and without the hat and port lines hooked up and here are the results
    -85% leak with lines connected
    -85.5% leak after disconnecting port lines
    -87% leak after disconnecting port AND hat lines
    Cheers. Jim.
     
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  18. Mike Canter

    Mike Canter Top Dragster

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    You can leave them hooked up and use the percent solely as your own reference but if you try and compare it to someone elses percentage then you have to be careful that you are both doing it the same way.
     
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  19. mbaker3

    mbaker3 New Member

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    Ok, now I am truly, totally confused! :eek:
    Because I am fairly new to this I am open to help here.
    "I thought" leak testing my barrel valve told me how much fuel was getting to the hat during idle conditions. I am not sure why I would want to compare my fuel conditions to anyone else's. ( I have a very fat, heavy truck, not a T/A rig that runs in the 5's) :rolleyes:
    My impression of the value of leak testing was that I could adjust how much fuel was being put into the engine at idle speed. Too rich and it could be very sluggish at the "hit of the throttle". Too lean and it could hurt performance and parts.
    Please, please, don't think I am trying to be a smart a$$, I'm am not! I am hearing that the reason that I am leak testing my barrel valve is ??? Well ...... Now, I really don't know why!
    Help!
     
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    Last edited: Jul 30, 2008
  20. WIZBANG

    WIZBANG Member

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    The fuel car is between 5-9 lbs at an idle rpm of 2700 !

    We shout for 7 lbs !
     
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