Port CheckValve Nozzle Pressure

Discussion in 'PSI Superchargers Tech Questions' started by Blown5402, Sep 25, 2013.

  1. Blown5402

    Blown5402 Member

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    On a screw blown alcohol promod hemi motor with a converter, what do most teams set the Checkvalve/poppit to come in at for the port nozzles? We have run a roots blower for many seasons, but now seem to need some help as when the port nozzles need to come in for the screw blower. THANKS for any help or suggestions-Jim
     
    #1
    Blown5402, Sep 25, 2013
  2. blown1969camaro

    blown1969camaro Member

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    we set our

    17 psi on port
     
    #2
    Last edited: Sep 26, 2013
    blown1969camaro, Sep 26, 2013
  3. Blown5402

    Blown5402 Member

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    Blown69camero-Port or Hat Checkvalve?

    THANK YOU Blown69camero, and that may be where I am having trouble, I just have a poppit or checkvalve on my portnozzles and it is set at 18 to 20#s pressure before it opens. I do not have a checkvalve or poppit on my hat nozzles. Please let me know if I am missing something? THANK YOU, Jim
     
    #3
    Blown5402, Sep 26, 2013
  4. Mike Canter

    Mike Canter Top Dragster
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    Normally you adjust the poppet so that the port nozzles are not on at stage. This can be different from car to car. Look at the pump pressure at stage and set the poppet a little above it. You can check it by taking a port nozzle line off and put it in a plastic milk jug while the car is brought up to stage rpm. Then I know some cars that have the port nozzles on while staging. So what you have to decide is if you want the port nozzles on or off during stage and set the poppet accordingly. Any poppet pressure in between makes little difference to the tuneup.
     
    #4
    Mike Canter, Sep 26, 2013
  5. rb0804

    rb0804 Active Member

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    DO NOT put a check valve in the hat. The port nozzles generally open anywhere between 17-20lbs, but realistiy could open at any pressue and really depends on your situation. What's the issue that you are having? Do you have dribblers? Are you trying to make it idle on the hat?
     
    #5
    rb0804, Sep 27, 2013
  6. Blown5402

    Blown5402 Member

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    2 cold cylinders at launch

    Trying to idle on the hat, it goes cold on 2 cylinders when at wide open throttle on the 2-step, then takes about 1.4 seconds to get those 2 cylinders back up to power making temperatures. I do not have dribblers, but going to add extra nozzles to the 2 cold cylinders for now and put them on a higher pressure check valve and lean the originals, and see if that may work better? THANKS! Jim
     
    #6
    Blown5402, Sep 27, 2013
  7. Mike Canter

    Mike Canter Top Dragster
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    Jim, tell me why you are adding extra nozzles to the the cold cylinders. If they are cold then that is normally caused by those cylinders being too rich. When on the Two Step do you have a fuel bypass solenoid on? Do you have a flow meter and if so how much fuel is going into the motor when on the Two Step? And lastly have you modified the V slot in he Barrel Valve for screw blower operation?

    When on the Two Step are you at Wide Open Throttle or are you at some position less than wide open for some reason?
     
    #7
    Mike Canter, Sep 27, 2013
  8. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    Fuel System

    I disagree with the methods being discussed here.

    IF we are talking about a system with 8 port nozzles, the normal check pressure for these ports would be 8-12 lbs.

    IF we are talking about a system with 16 port nozzles (dribblers) many are set with dribblers 12-17 and ports anywhere from the low 20s to 30 plus. As discussed in other threads, if you are leaving on a two step, the 16 port system is really obsolete because the methodology is to control cylinders at stage (part throttle) with dribblers then bring the ports in after launch to keep the cylinders evened up at WOT.

    Most of the cars I have worked with have check balls in two of the 4 hat nozzles going through the PSI. Every car I have ever worked with all 4 hats wide open have had extremely rich cylinders at stage unless the barrel valve was lean and mean.

    To correct your problem I would advise either leaning barrel valve some or pulling more fuel away at stage on two step. Pay attention to your head temp if you lean the bv.

    If you want to know the real correct answer to your question, send your fuel system to someone like Randy Anderson or Spike Gorr and get it flowed, set up and a baseline. If you figure up your actual cost per run to go to the track and run your car vs what it cost to get your fuel system flowed, it is very hard to figure out a fuel system on your own quicker than you can if you just spend the money to get it flowed. Not to mention those guys can answer a lot of other questions for you on your motor combination and car.
     
    #8
    Will Hanna, Sep 27, 2013
  9. overkill69

    overkill69 Member

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    port

    if the car will idle you can launch wide open on the 2 step and all the checks are meaningless.

    If you have a flowmeter you should be able to get the thing happy.
    I had all my stuff flowed just to get the baseline tuneup and make sure the pump was happy before I wasted time at the track.
     
    #9
    overkill69, Sep 27, 2013
  10. Blown5402

    Blown5402 Member

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    4.75gpm 2-step gpm flow

    Mike, on the 2-step, I have 4.75gpm through the flow meter. I am real close on my tune-up, but want to heat up 2 colder cylinders and will split the fuel flow (hopefully atomizing better too) with 2 nozzles for each cold cylinder, cutting down/leaning the fuel at idle and on the 2-step, and then on a timer or a check valve or dribblers bring in the other nozzle in for each cylinder to keep the temperatures where I want them. I do have a solonoid bleeding fuel on the 2-step and that really helped keep some heat in the 2 colder cylinders. I need the 2 cold cylinders to build some heat as my motor is a smaller 438ci BAE and I need a little more for the 60' and the 330' to reach our goals for this year! THANKS to all for the help and comments. I have been building/racing blown motors for 20 plus years with roots blowers, but the screw is a different tuning story as far as I am concerned. I am wide open throttle on the 2-step and was told that the BV slot modification was not needed; leaving at WOT. I have the barrel valve with the slot modified for a screw, and have not used it yet? It has taken us 4 trips to the track to get nearly all of the bugs worked out on a new car/motor/tarns combo, and just wanting to pick up a little more ET before cold weather shuts us down! THANKS again and I do not worry about anyone stealing or taking over the threads, because I learn more everyday from the knowledge on here. The PSI distribution plate various patterns will be tried on the dyno this Winter too-THANKS again! Jim
     
    #10
    Blown5402, Sep 27, 2013
  11. scott hall

    scott hall Member

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    I just spent a few weeks trying to figure out what Will Hanna has just said to do on a PSI blower set-up on a two step.

    Mine is a one of kind combo that took a lot of figuring things out. But Will is correct, when you have a fuel system person flow your stuff, they will lead you in the correct direction. Mike Kopchick at Rage Fuel Systems did all mine.

    A flow bench will show you the different pressures that the port, hat, and idle poppet are at during the same RPM's. Once you know that, the rest will make sense when you make changes from reading data aqc.

    Scott Hall
     
    #11
    scott hall, Sep 29, 2013
  12. blownapex

    blownapex Member

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    barrell valve

    your last post said you had the modified barrell valvebut not using it
    dont use the v slot roots spool it will be rich and flood the engine
    read the psi book for modifying the spool valve you may need to cut it
    deeper for that smaller engine
     
    #12
    blownapex, Sep 29, 2013
  13. Mike Canter

    Mike Canter Top Dragster
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    You can move the fuel pressure pick off point around off the data logger and read fuel pressures any where you want without having to bench flow the system and if you have a flow meter then every run is like a flow bench run.
     
    #13
    Mike Canter, Sep 29, 2013
  14. Blown5402

    Blown5402 Member

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    Flow Meter

    Mike, I have a flow meter and I am using different points along the fuel pressure line behind the barrel valve and checking pressures and times into the run. I have been picking up .05 to .07 each run and hope to continue next weekend probably our last race of the year, but need to our reach goals to be able to set plans for next year! THANKs for all of the help and everyone else, as we all know, each motor/trans/chassis combination works some differently too! Also going to try and get 100#s off of the car during the Winter too-THANKS-Jim from TN
     
    #14
    Blown5402, Sep 30, 2013

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