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QV motor vaccum reading/ starting characteristics

Discussion in 'Technical Q&A' started by abarthracer, Apr 9, 2004.

  1. abarthracer

    abarthracer Formula Junior

    Dec 6, 2003
    373
    Falmouth, Cape Cod
    Full Name:
    david S.
    Can anyone tell me what the vacuum reading should be at the intake plenum. I am going off of the nipple that is next to the CSI. At about 1000RPM mine is at 9.5-10 in. Seems low to me.
    Also, you guys that have perfectly running motors, what is a normal running scenario from cold. IE, it starts after 4-5 cranks, idles at 2Krpm for 3 min, then back to 1000RPM etc. I want to know if my expectations are unrealistic. And lastly, is there a base line setting for the air bleed screw under the plenum. Does it react like a normal idle speed mix screw as in use it to get the fastest idle possible and then use the idle speed screw to adjust the final setting.
    Thanks
    1985 QV Mondial
     
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  3. 4re308

    4re308 F1 Rookie

    Jun 13, 2001
    4,723
    Woodstock, GA
    Full Name:
    Mitch D
    David, when my car is dead cold, it starts almost immediately and idles at 1100 right off the bat. However, after a drive during the winter, I go to crank her up, and it goes right to 2000RPM and stays there for a 1-2 minutes. I HATE when it does that. It just sounds bad to me. It think my cold start valve is no good.
     
  4. pma1010

    pma1010 F1 Rookie

    Jul 21, 2002
    2,559
    Chicago
    Full Name:
    Philip
    David
    Idle vacuum doesn't sound too far off. My carb'd 77 with stock cams would pull about 10 inches (with the comp cams it is much lower) at idle.
    Philip
     

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