hi-speed control

Discussion in 'PSI Superchargers Tech Questions' started by wildride boy, Oct 26, 2005.

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  1. wildride boy

    wildride boy Top Sportsman Racer

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    Hi
    I'M running my 509 bbc with electric controled hi-speed by-pass valves. I began this set up some years ago because i did'nt have access localy to somebody can tune my fuel system , I think it works ok . I think it's easier for me to tune with electric one.
    I saw some pro mod cars both set-up installed on the same car , but i don't know if it operate it together . I use .090 to .100 main jet , first hi speed jet .010 at 6700 rpm and second .015 at 7500 rpm . Can somebody explain me if there are any advantage of one set-up over the other
    Thanks
    Claude
     
    #1
    wildride boy, Oct 26, 2005
  2. wildride boy

    wildride boy Top Sportsman Racer

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    adds

    The other set-up refered is spring load controled by-pass valve
    thanks
     
    #2
    wildride boy, Oct 26, 2005
  3. Mike Canter

    Mike Canter Top Dragster
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    When you say spring loaded are you refereing to the standard pressure type? The major problem I see with the standard pressure type is that when adjusting the main jet to compensate for DA the fuel pump pressure changes and so does the activvation point of the high speed leanout. To make the pressure activated high-speed lean out occur at the same rpm you must either shim the spring to re-adjust the the release point or change the nozzle jet to bring the fuel pressure back to the same point or just leave it alone.

    I much prefer an rpm activated high speed lean out because it always occurs at the same RPM. I believe that there are some rules out there in certain associations that prohibit eletronic fuel control and that might be a problem for some.
     
    #3
    Mike Canter, Oct 26, 2005
  4. wildride boy

    wildride boy Top Sportsman Racer

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    Thanks Mike for the response.
    The other set-up i talked about is effectively standard hi-speed by-pass.
    Can you tell me how many electric hi-speed valves are normaly used these days by alcohol cars. Can somebody tell me the approximate rpm to adjust it if more than two.
    Thanks
     
    #4
    wildride boy, Oct 26, 2005
  5. Mike Canter

    Mike Canter Top Dragster
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    I have seen both one and two hi-speeds on a car. I have been told the correct way to set the first so it bypasses 100-200 rpm prior to torque peak. Normally that varies around the 6500-7500 rpm area. The second would be whatever makes it go fast. Never seen a rule on when to turn on the 2nd one. If somebody else has any ideas then please help.
     
    #5
    Mike Canter, Oct 26, 2005
  6. LOTSOHP

    LOTSOHP Jr. Dragster

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    Why always high speed "lean out"

    Hey mike, just wanted to ask. Why would you want to lean an engine out in high gear? or second gear? sounds like it would make someone run over alot of parts.
     
    #6
    LOTSOHP, Oct 28, 2005
  7. Leon

    Leon New Member

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    On a mechanical fuel pump mounted off the cam,the faster the engine goes the faster the pump goes.At one point the fuel flow outruns the requirements of the engine. A hi-speed will bleed off excess fuel to put the engine back into its happy state.
     
    #7
    Leon, Oct 28, 2005
  8. Mike Canter

    Mike Canter Top Dragster
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    When using a Roots type blower the faster you spin it the more boost you make and the hotter the air charge becomes coming out of the blower. This is caused by the compressing of the air and by the friction of the stripes against the rotors and case. As the incoming air charge heats up the volumetric efficiency of the motor is reduced so less fuel is required to make the correct AFR. As stated the fuel pump does increase its output as the motor increases RPM and almost matches the fuel requirement of the motor but the fuel curve tailoring is down by the high speed leanouts.

    PSI blowers are easier to turn because they have no stipes so less heat is generated so in most cases you add fuel when the rpm goes up and it makes more boost.
     
    #8
    Mike Canter, Oct 28, 2005
  9. LOTSOHP

    LOTSOHP Jr. Dragster

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    Is this waht you look like at a thousand feet or 330>

    Thanks for the info guys, so what I gather from mike is that "most people" tune a roots combination opposite than a screw combination because the boost is lower on the roots? I wanted to ask wildride what rule restrictions are you working with, most people I have been around use solenoids to curve their fuel system. on a three speed deal it would have two solenoids activated with each gear change. It could be activated with air if the car is air shifted or elec. if you use a switch on each gear change. THis would be more consistant because you would know exactly when the change occurs making it easier to tune especially with a computer on the car. you match the gph with the rpm and watch the egt's etc. fuel management systems can be set up the same way, each stage of the system is activated by air when the gear change is made and you can use asmany stages as you want, each one has a changeable jet in it so you can curve it either way you want.I dont know what rules you have to abide by or what your running?
     
    #9
    LOTSOHP, Oct 29, 2005
  10. Mike Canter

    Mike Canter Top Dragster
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    No that is not exactly what I said. Although what you said is correct in that the Roors has less boost than a PSI. The main reason for the difference in either adding or subtract fuel as the motor RPMs is the temperature of the air charge coming out of the blower which changes the volumetric efficiency of the motor. The Roots heats the air more than a PSI,
     
    #10
    Mike Canter, Oct 29, 2005
  11. DQUES

    DQUES Member

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    I don't think ihra or nhra allows the fuel system to be controlled by anything electronic . Most people run a air switch under the throttle pedal that activates air timers that open and close different jets at preset times . Claude , if you were to ad the area of a .010 and a .015 jet , then ad that # to the area of a .090 main jet , this would be your final jet area . You might not be opening up enough area with those 2 small jets to really affect the fuel system much . I would figure it out but I cannot even find a area chart that goes below a .020 orifice . When both of your hi spds are open you are only around a .092 or .093 final jet area . Just my thoughts on it and I have been wrong before .
     
    #11
    DQUES, Oct 29, 2005
  12. Bob Kraemer

    Bob Kraemer New Member

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    To figure area of a circle or jet you multiply radius x radius x 3.1416
    Example area of a .020 jet
    .01 x .01 x 3.1416 = .0003416

    If anyone is intresred I have downloaded some Windows & DOS based programs for weather, square area, fuel injection etc!!

    Most DOS programs will work on Windows 95, 98, ME, 2000 & XP

    Hope this helps
    Bob Kraemer
     
    #12
    Bob Kraemer, Oct 29, 2005
  13. flash

    flash top alcohol

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    #13
    flash, Oct 30, 2005
  14. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    a standard psi fuel system is fairly simple. you can run real fast with just a main jet, and a 'pump loop' to effectively control your pump size with another jet. i've seen fuel systems that had lean outs controlled by gear shifts and timers. however, you have to have the fuel back in a psi by high gear.

    the most common leanout you see on a psi is the low gear leanout, where you lean it through low, then put the fuel back in it either at, or around the 1-2 shift.

    in nhra tad and tafc, no fuel system functions can be controlled electrically, so all timers and solenoids must be air operated. i think in promod, electric timers can be used. however, in tad and tafc, electric timers can be used to control ignition functions.
     
    #14
    Will Hanna, Oct 30, 2005
  15. wildride boy

    wildride boy Top Sportsman Racer

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    Hi guys, sorry i wasn't there to replay more quickly.
    LOTSOHP , i'm intop sportman class , i didn't see anything in the ihra rules book that tell me it's illegal , i used 2 msd rpm activated switch coupled to 2 NOS nitrous solenoid , i used only rpm signal , i don't have any reference with which gear i am. I was thinking it's more accurate this way. I used 3 speed lenco with converter.
    DQUES & BOB : thanks for the explanation about calculation of jet area , i know this calculation system for long time , but i never never think to apply it to my fuel system ( I only + jets size ) .
    WILL : Your post is very interesting , can you explain more about : PUMP LOOP JET & " YOU HAVE TO HAVE THE FUEL BACK IN A PSI BY HIGH GEAR " . Why use only in first gear.
    Thanks Claude
     
    #15
    wildride boy, Oct 31, 2005
  16. Leon

    Leon New Member

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    Hey Bob,what injection programs you got?Can you post em or do they need to be emailed? Ive got all kinds of stuff for weather and ive got a nozzle area chart.Cant have too many.LOL
     
    #16
    Leon, Oct 31, 2005
  17. Bob Kraemer

    Bob Kraemer New Member

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    I'll have to e/mail them.
    Some of the programs will require Winzip & Microsoft excel.
    Leon I tried to e/mail but your address wasn't listed. Post back or e/mail me. Leon I got your message.
    Note to all who asked for the files. Some of the programs I have never used at the track so I am not sure how accurate they are. In other words don't kill the messenger. :D
    Take Care
    Bob
     
    #17
    Last edited: Oct 31, 2005
    Bob Kraemer, Oct 31, 2005
  18. funnycarguy 230

    funnycarguy 230 New

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    Bob If You Would Email Me The Figures For The Fuel Systems Thanks Jamie Funnycarguy@netzero,com
     
    #18
    funnycarguy 230, Nov 1, 2005
  19. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    high gear

    since you dont run into the inefficiency problem you do on a roots, its making hp as the rpm's and boost go up. if you were to lean it out all the way through high, you're more than likely going to blow it up. you can get away with leaning it in low, then throwing the fuel back to it. you lengthen the fuse to speak. basically you build some heat with that low gear leanout, then throw the fuel to it, and it burns it.
     
    #19
    Will Hanna, Nov 1, 2005
  20. Fuel Cars

    Fuel Cars AA/AM

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    Bob, can you email me the programs also, use this LINK for email.

    Thanx in advance.
     
    #20
    Fuel Cars, Nov 1, 2005
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