Couple of fuel system questions

Discussion in 'PSI Superchargers Tech Questions' started by 37hemi, Feb 19, 2013.

  1. 37hemi

    37hemi New Member

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    Just put in a 462ci BBC into my car for a few meets till my normal engine comes out of the shop. It has a teflon 10/71 standard helix making 26lbs. Bird hat with port nozzles, and its a power glide, 110 pump and a supermag4. Firstly when I pull the fuel shut off to turn it off in the pits it seems normal, and the end of the run it really brings the rpm up high. Any ideas why this may happen? second question is I checked my idle check valve and it is set at 10lbs. I have read many things about were it should be set, 6-8lbs seems to be common but I would like to no the reason and difference between high and low settings? Also should I set mine lower and why? My high speed isset at 62lbs with a 60 pill and port nozzles come on at 18lbs. Hat nozzles 2x50 2x42 4x48. Ports 2x34 2x36 2x44 2x48. running a 125 main pill. Only done 1 1/8 meet. Seemed a little fat but hard to tune on a 1/8th track. Any advice on the tune up at all???
    Thanks
     
    #1
    37hemi, Feb 19, 2013
  2. Mark Leigh

    Mark Leigh Member

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    Exactly WHEN do you pull the fuel shutoff after making the run ?????????
     
    #2
    Mark Leigh, Feb 19, 2013
  3. 37hemi

    37hemi New Member

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    In the braking area just before the turn off
     
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    37hemi, Feb 19, 2013
  4. Animal1

    Animal1 Member

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    when you shut the fuel off it leans the motor thats why she's revvin up...also could be your shuttin off the fuel and gettin on the brakes hard to cause it to rev up faster
     
    #4
    Animal1, Feb 19, 2013
  5. Mike Canter

    Mike Canter Top Dragster
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    The crack pressure on the idle return will set the range of the barrel valve idle adjustment. The higher the setting the less the percent leak down on the BV to get the correct idle. If your idle mixture is ok that the motor is responsive coming off idle and the staging EGTs are right around 625* then all is good. If your staging is to rich and the EGTs are too low then one raises the crack pressure and reduces the percentage of leak down. I use 8-10 on the idle poppet and think you are just right. I think your port poppet is a little high. When you stage you don't want the port nozzles on but if you make that port poppet crack pressure too high then your sixty foot may suffer. You might try lowering your port poppet to 7-10 psi and see if it makes it more responsive off the line.
     
    #5
    Mike Canter, Feb 19, 2013

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