Orifice Constant Numberto use in Pump Calcs Flow Question

Discussion in 'PSI Superchargers Tech Questions' started by TADHemiracer, Mar 10, 2013.

  1. TADHemiracer

    TADHemiracer Member

    Joined:
    Dec 9, 2010
    Messages:
    359
    Likes Received:
    13
    I have been using the Pump Calcs orifice flow calculator online but I am not sure which "Orifice Constant" number I should be using for alcohol. The choices offered at that site is .51, .62, .82, .97 and 1.55.
    Any advice on which is the correct number I should be using?
    Thanks in advance.
    Barry
     
    #1
  2. Patrick Hale

    Patrick Hale Member

    Joined:
    Aug 7, 2010
    Messages:
    58
    Likes Received:
    0
    #2
  3. TADHemiracer

    TADHemiracer Member

    Joined:
    Dec 9, 2010
    Messages:
    359
    Likes Received:
    13
    Orifice Constant

    I see that I left off some important info about my particular uses for the pump calc number. I am trying to calculate how much alcohol would go through an Enderle main pill that has the bevel on the screwdriver slot side. I saw the drawing for the vaious orifice styles but none were similar to the Enderle main pill as far as I could tell.
    The drawing for .62 shows to be for a straight wall portion of the pill to be 1/4 of the hole diameter so if the hole is .100, the wall portion would be.025 or less.
    The drawing for .82 shows to be for a straight wall portion of the pill to be 2 to 3 times the diameter of the hole. So if the hole is .100 then the straight wall portion would be .200 to .300 or so. This seems to be closer to the Enderle pill than any of the other orifice styles shown on PumpCalc.
    Am I missing something?
    Thanks again,
    Barry
     
    #3
  4. Patrick Hale

    Patrick Hale Member

    Joined:
    Aug 7, 2010
    Messages:
    58
    Likes Received:
    0
    Mike @ Rage Fuel Systems (843) 623-3500

    Call Mike and tell him what you are doing. He knows all the flow coefficients from his years of bench flow testing fuel systems. As I recall, the Enderle main pill is closer to the 0.51 PumpCalcs choice. But Mike Kopchick is the expert.

    Patrick Hale
    www.DragRacingPro.com
     
    #4
  5. Dave Koehler

    Dave Koehler Member

    Joined:
    Sep 10, 2004
    Messages:
    441
    Likes Received:
    14
    To the OP. Unless you have a reason the fuel path on the enderle is through the square edge side, not the screwdriver side. That taper was added to keep people from screwing up the edge of the hole with screwdrivers.

    Dave Koehler
    http://www.koehlerinjection.com
     
    #5
    Last edited: Mar 10, 2013
  6. TADHemiracer

    TADHemiracer Member

    Joined:
    Dec 9, 2010
    Messages:
    359
    Likes Received:
    13
    Main Pill Fuel Flow Direction

    I understand that the flow is from the smooth side. I used the bevel and slotted description to describe the KIND of pill, not the flow direction. My flow is still from the square edge side. That still does not change the smooth wall dimension of the pills. I am trying to figure what size pill to put in the pump loop. I need to lose 3 gpm from my 1100 Enderle pump. I will call Mike at Rage tomorrow.
    Thanks for everyone's help.
     
    #6
  7. Mike Canter

    Mike Canter Top Dragster
    Staff Member

    Joined:
    Mar 10, 2004
    Messages:
    4,599
    Likes Received:
    178
    At what fuel pressure do you want to lose 3 gpm on a standard Ederle bypass jet? I think you are making this way to hard.
     
    #7
  8. TADHemiracer

    TADHemiracer Member

    Joined:
    Dec 9, 2010
    Messages:
    359
    Likes Received:
    13
    Orifice Constant

    I am trying to lose 3 gpm at 150 psi. I wanted to be sure of the constant number to be reasonably sure that the flow numbers I use are accurate enough to use. It seems that the flow from .51 to .62 and even .82 are far enough apart that it would make a sizable difference in flow. I would also be able to use that constant number in other calculations that use the same style pill, as in a high speed and other lean outs or a staging fuel bypass circuit. Without an accurate constant number then I see no reason to even use the calculator much less trust the calculations at all.
    Thanks
     
    #8
  9. Mike Canter

    Mike Canter Top Dragster
    Staff Member

    Joined:
    Mar 10, 2004
    Messages:
    4,599
    Likes Received:
    178
    #9
  10. ta455

    ta455 Member

    Joined:
    Nov 26, 2003
    Messages:
    197
    Likes Received:
    2
  11. Mike Canter

    Mike Canter Top Dragster
    Staff Member

    Joined:
    Mar 10, 2004
    Messages:
    4,599
    Likes Received:
    178
    Check with Ralph Gorr first because all his charts were based on water flow and not methanol flow and that makes a big difference. I had sent him new charts for methanol but not sure he switched them
     
    #11
  12. ta455

    ta455 Member

    Joined:
    Nov 26, 2003
    Messages:
    197
    Likes Received:
    2
    is there a number you could multiply/divide water numbers to get methanol numbers?
     
    #12
  13. ozrace

    ozrace New Member

    Joined:
    Dec 8, 2012
    Messages:
    23
    Likes Received:
    1
    Using a flow chart like this is a lot more effective than trying to calculate an individual orifice.. but be aware that every time you change the main pill, your fuel pressure will change and so will the flow of the loop pill.
    You can't just flow 3 gpm all the time.. you have to take the loop, main and fuel pressure into account.
     
    #13
  14. Patrick Hale

    Patrick Hale Member

    Joined:
    Aug 7, 2010
    Messages:
    58
    Likes Received:
    0
    #14
  15. TADHemiracer

    TADHemiracer Member

    Joined:
    Dec 9, 2010
    Messages:
    359
    Likes Received:
    13
    Irifice Constant

    Ozrace, The 3 gallon number I mentioned was to be at the full 150 psi. Actually, changing ANY orifice in the system affects pressures and flow numbers as a result. Simple hydraulics.

    Patrick, I had a long day yesterday and have not had the chance to call Mike at Rage yet. I will try to find the time today and post his answer when I get it.

    It is looking to me that there may not be a specific "orifice constant" after all. That being said, the pump calc may not be as dependable as Gorr's flow chart. The pump calcs and the Gorr flow data are going to give me a good starting point.

    Thanks everyone!!
     
    #15
  16. TADHemiracer

    TADHemiracer Member

    Joined:
    Dec 9, 2010
    Messages:
    359
    Likes Received:
    13
    Mike at Rage convo about orifice constant

    Ok, the verdict is in.
    A. Mike at Rage said that a .109 orifice would flow close to 3 gpm (2.98 actually) at 150 psi.
    B. I mentioned the pump calcs orifice constant question and he said the number would be between the defaults offered of .51 or .62.
    C. He also said that those default constants work pretty for what it was designed to work with like hydraulics but are not really close enough to use for fine tuning an alcohol race motor.
    D. Mike also said that splitting the loop into two pilled circuits would give more ability to control the fuel curve. One pill at the pump. Second pill at the D block.
    Thanks for everyone's input!!
    Barry
    Thanks for everyone's input!!
     
    #16
  17. rb0804

    rb0804 Active Member

    Joined:
    Aug 7, 2010
    Messages:
    655
    Likes Received:
    36
    The second pill being inline between your port check and the distribution block? Was there an approx. percentage to between the two or will they be split 50/50?
     
    #17
  18. TADHemiracer

    TADHemiracer Member

    Joined:
    Dec 9, 2010
    Messages:
    359
    Likes Received:
    13
    Second Pill and Percentage

    I am certainly not qualified to answer those questions you posed. My tune-up is so far out in left field that the stadium lights don't even go that far.
    My port check is directly into the port D block so in my case the secondary pill would be taken directly off of the D block with another check valve. That being said, the poppet crack pressure would also influence the fuel curve.
    My D block has enough ports in it to put a second check valve and pill. I think the reasoning was to get the second pill closer to the nozzles where the pressure is a little lower but then again my Hi Speed is set at 100# for a beginning point.
    There was no discussion about percentage.
    Here again, I can see that the correct answer to getting a baseline tune on my race motor, given the pump I have with the set-up I have with the unflowed nozzles I have and with the unknown flows of my high speeds, lean outs and fuel return hoses is to send these parts to a qualified shop and let them do what they do best...flow and tune.
    I keep resisting spending the money to get it done but as time goes by and I see the burnt parts pile getting higher and higher, I could have saved money and gone fast at the same time.
    Thanks again to all that posted.
     
    #18

Share This Page