high speed question

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by rb0804, Nov 16, 2010.

  1. Critical Mass

    Critical Mass Member

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    Thanks Mike for the reply. I do have a pressure sensor between the pump and BV and see the sawtooth pattern you describe. I didn't think of the pump saver poppet because it is set at 180 psi. I'll check the pump saver again.
    Thanks, Joe
     
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  2. Mike Canter

    Mike Canter Top Dragster

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    I believe what you are seeing is normal gear tooth pressure pulses but if you want to print screen from your computer displaying it from the data logger for another set of eyes you can email me a picture at mike.c@mindspring.com
     
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  3. BUTCH

    BUTCH Member

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    fuel pressure

    Mike, what Is the best to limmit the amount gear teeth pressure pulses that the computer see's ? we are pulling the pressure off the top of the waterman pump>

    thanks

    Butch
     
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  4. Mike Canter

    Mike Canter Top Dragster

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    If it is just upsetting you on the Racepak or other data logger then right click on the appropriate box for the pressure above the graph and move the slide bar for the "smoothing" to the right until it flattens out the display some. Just be warned to much "smoothing" delays the data for that trace on the graph just a little. So if you were looking for a pressure change at 1.5 secs then it may now occur at 1.55 or 1.6 seconds depending on how much smoothing you have turned on. You can do smoothing on just about all traces on the graph.

    What smoothing does is average out the high peaks and low dips so it displays a straighter line.

    Now to actually reduce the pulses in the system then you need an accumalator of some type. I have done it my using a inline System One fuel filter but you would have to put the pressure sensor above the filter for the smoothest display.
     
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  5. rb0804

    rb0804 Member

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    does it matter where you put the main jet? I was looking through a few diagrams from Gorr and the one with the square enderle they had a 'high speed' tee with a jet can and a popet for the main jet and they put a blank in the main. Could you do the same thing but opposite by leaving no jet in the barrel valve and put the jet AND popet assembly downstream further (like on the return block like I mentioned earlier)? I would think that it makes no difference where the jet is, as long as it is in there somewhere. It might make a difference on how your barrel valve is setup whether the jet is acted upon before or after the spool (referring to the old Pete Jackson vs. the new JT stewart style PJ. On the old cast one a change of the jet shows up at idle/stage and it doesnt on the new style). Thanks.
     
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  6. Mike Canter

    Mike Canter Top Dragster

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    No it doesn't make any difference where the main jet is located BUT why would you move it. First the main jet circuit is actually a combination of the main jet, the high speed and the pump sizer circuits. You can eliminate some and replace it with control in the other as has been stated in a previous post but that is not the same for all engines because it is different if you launch on a Two Step or not. All these circuits bypass fuel and the poppet controls at what point they bypass fuel. The staging fuel flow is important and like I said varies a little depending on if you are using a Two Step, air control or nothing. Then there is the fuel control in the actual run. The trick to all this is control, repeatability and stability. You have to be able to control the fuel flow with great accuracy so the fuel curve is what you want when you want it. I you can't do that then you can't change it at different points during the run. If you run a different setup then you have to be able to tune it to the fuel flow you want and when and that takes time. The big question is why you would want to change from a proven stable setup. Believe me the problem with most racers and especially beginners is not the location of all the jets but getting the fuel curve correct for the RPM and other factors during the run.
     
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  7. Dale Finch

    Dale Finch New Member

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    Hey AJ481x.......I am not going to let your statement go by without you explaining yourself. Unless I am missing something here every fast car out here runs fuel management mostly off the high speed port on the barrel. And that is technically a multi pill high speed. What do you mean it doesn't help?
    Dale
     
    #27
  8. aj481x

    aj481x Member

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    Everyone has fuel management of some sort. I was referring to the straight "high speed leanout" which is used based on the theory that the engine is less efficent at higher speed and thus needs less fuel. This helps on injected motors but if you really study a blower motor there is no reason for this. The motor automatically adjusts as it leaves both the air and the fuel it can't use in the intake as the speed increases. It really wants a very similar amount of fuel/air in the cylinder at all times. The fuel and timing requirements are pretty simple and fuel and timing management are mostly needed for traction and to control the max temp in the cylinder.
     
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  9. rb0804

    rb0804 Member

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    Does anyone use the air operated valves on the back side of the barrel valve? All of the diagrams that I have seen (like the PSI stuff) takes the fuel management off directly off the pump. Is it done like that way because the jets would be 'less sensitive' to whats going on post barrel valve, thus keeping the jet diameter in a reasonable range?
     
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  10. Mike Canter

    Mike Canter Top Dragster

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    One should first ask why anybody would call a High Speed a High Speed. We don't turn it on at high MPH or high RPM. All it is is an extension of the main jet circuit that you can turn on at the right time to help adjust the fuel flow right after launch. One still adjusts the size of the main jet with the High Speed on and the pump sizer on. Yes you can get rid of the High Speed and increase the size of the pump sizer jet and/or the main jet and bypass the same amount of fuel so the tuneup is basically the same during the whole run with or without the High Speed. Maybe one should understand the reason that with some systems you don't want to start bypassing right away so you use a poppet or timer on the High Speed and the Pump Sizer circuits to delay the turn on.

    You can place the solenoids before or after the BV. The only difference is a little more flow through the bypass jets when before the BV because the pressure is a little higher so you have to adjust the size a little. You are still going to have the same GPM bypassed regardless where it is located and the same final GPM going into the motor.
     
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  11. rb0804

    rb0804 Member

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    You have a PM
     
    #31
  12. SoDak

    SoDak Active Member

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    I ran some scenarios and here is what I found.

    With the High Speed T located right off the 3 way shutoff which is right on the pump, I played with the pill before the poppet and than after it. At first I had 3 PSI sensors in place, 1 was pump psi, 1 was between the pill and the poppet and 1 was after the poppet between it and the tank. The pill was a .075" and the poppet crack PSI was 72 lbs. There was no psi between the poppet and the tank (I don't think anyone will be surprised with this) and there was a psi drop between the pump psi and the psi on the other side of the pill.
    The GPM difference between the pill before the poppet and the pill after the poppet went like this. After the poppet opened (in the low 4000's for RPM) the difference in GPM at 4750 RPM was 0.15, the pill first poppet second had more GPM to the motor. At 8000 RPM the difference was 0.10, the pill AFTER the poppet now had more fuel to the motor.
    So in this setup, putting the pill after the high speed leaned in the lower RPMs and richened in the upper RPMs.
    The poppet was set with an air pressure regulator at 72 psi, on the flow bench it would get to about 82 psi and flat line, the psi would not go higher even though the system psi continued to climb. I changed the spring to a radically different one, although shimmed it to open at the same PSI (within 1 psi) thinking the rate of the spring would change things. It still flat lined at about 82 psi and the GPM seemed to change by about .05 but that small amount is pushing my limits of repeatability. In the very least one can say it changed very little.
    For this fuel system, changing the main pill by .005" will change the GPM by about .10-.12. I bring this up to help relate the above GPM numbers to pill sizes.
    I hope this makes sense and helps someone:cool:
     
    #32
  13. rb0804

    rb0804 Member

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    Thanks for the good, hard info. I tried to send you a PM but your inbox is full.
     
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  14. SoDak

    SoDak Active Member

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    rb0804, try the PM again
     
    #34
  15. Critical Mass

    Critical Mass Member

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    Problem Found

    In post #21 I said the pressure in my port line was all over the place due to my high-speed. I discovered that the electrical connection to the sensor was vibrating and causing intermittent contact during the run. This was a good lesson for me. In the future I'm going to better secure all my sensors. I'm passing this info on to others to be aware of.

    Thanks Mike for offering to look at the data with another set of eyes; I'm sure you would of caught it right away. Joe
     
    #35
  16. rb0804

    rb0804 Member

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    Thanks for the update, this will save someone some headaches in the future. Are you planning on moving the high speed back around to the way it was to see if there is a difference?
     
    #36
  17. rb0804

    rb0804 Member

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    pressure regulated high speed

    Has anyone tried the Kinsler style high speed diaphragm bypass? I am just curious if there would be a flow and/or pressure difference when compared to the spring popet.
     
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  18. Critical Mass

    Critical Mass Member

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    rb0804

    Yes, I like more fuel for the launch. It leaves pretty hard, 4.361 sec in the 1/8, but this a boat.
    Joe
     
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  19. SoDak

    SoDak Active Member

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    Are you a fly on my shop wall?:D This is next on my list...
     
    #39
  20. rb0804

    rb0804 Member

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    Just thinking out loud. I would be curious to see the results. Keep us posted and thanks for the good data.
     
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