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Thread: "Performance" cam setting = Won't idle lower than 1000rpm when in gear

  1. #1
    Join Date
    Jun 2015
    Location
    Rochester, NY
    Posts
    11

    Default "Performance" cam setting = Won't idle lower than 1000rpm when in gear

    I have a mopar 440 built to about 500hp. Cam specs are attached below..... I have my system setup for a "performance" cam........

    At startup, seems to take a few minutes for the car to warm up before it won't die out (if I don't feather the gas peddle).

    No matter what I set the target RPM to, when in gear, it idles around 950-1000 rpms..... If in idle, its up around 1300-1400rpm. Fluctuates a bit in idle.... almost as if it races a bit, then backs off.

    Currently the system is NOT controlling timing. When I was on a carb I could idle as low as 600 rpms easily.

    Thoughts? What should I look at? Possible changing the default cam setting off of "Performance"? Mild?

    I can get more info once I get home in regards to what all my settings are at.

    Thanks!
    Phil

    Cam_Specs.jpg

  2. #2
    Join Date
    Jun 2015
    Location
    Rochester, NY
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    Default

    Um.... according to this:
    cam_duration.JPG

    My "Cam Duration @.050" is 246 degrees.......... which is JUST under the 250 degree limit.

    What would happen if I went to a mild cam setting? Too far out of wack?

    I'll post all of my settings once I get home.

  3. #3
    Join Date
    Jun 2015
    Location
    Rochester, NY
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    Default

    My current settings:
    Cubic Inches: 446
    # of cylinders: 8
    Camshaft Type: Performance
    Fuel Pump Type: PWM No Regulator
    Air Pump Equipped: No
    IDL RPM Target: 900
    Rev Limit: 6500
    Timing Control: Disabled

    A/F Targets:
    Idle: 13.5
    Cruise: 13.5
    WOT: 12.3
    Nictrous: OFF
    Boost: 11.9

    Timing Disabled

    Pump Squirt: 25%

    Power Valve Enrich: 19%

  4. #4
    Join Date
    Jan 2010
    Location
    Brisbane, Australia
    Posts
    1,578

    Default

    How many steps is the IAC at hot idle?

    Gary
    Regards, Gary

  5. #5
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    Jun 2015
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    Rochester, NY
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    Default

    Hi Gary,
    I'll fire it up tomorrow, get it up to temp...... and check the IAC at hot idle....... Do I check in gear or neutral?
    Phil

  6. #6
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    Hi Phil,
    If the target is 900 rpm, then in neutral I would expect IAC of 5-20.
    Yours sounds like if target is 900, and it's still too fast in gear, IAC is probably at 0.
    Then in neutral with no load, the engine races with the IAC still at 0.
    Close both primary and secondary a fraction at a time until you get the IAC steps into this 5-20 zone.
    I would expect IAC in neutral about 5-20, then in gear could be about 40-50.
    Gary
    Regards, Gary

  7. #7
    Join Date
    Jun 2015
    Location
    Rochester, NY
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    Hi Gary,
    Drove the car around last night, let it warm up.

    Just as you expected, IAC when idling was 0. When in gear, IAC was 0.

    I'll try to close the butterflies slightly and see what happens. How do I know if I have the primary & secondary in the correct possition? Will the primary affect idle IAC and secondary in gear.... or they should both be cracked slightly open the exact same?

    When I cold start the car.... it fires right up, then stumbles and starts to die out unless I catch it by feathering the gas pedal. Once it is warm it won't do that.

    Thanks!
    Phil

  8. #8
    Join Date
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    Make the primary and secondary open by the same amount.
    Back both speed screws out until the screw is off the lever, turn in until touched, then open both by 1/2 turn to start with.
    They don't really need to be exact.
    Target of 5-15 IAC steps hot idle in neutral.
    Gary
    Regards, Gary

  9. #9
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    Jun 2015
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    Thanks again Gary! I'll report back once I try this out. <Fingers Crossed> . If I can get the IAC dialed in better..... think I might get my idle speed lower than 900?

    Thanks,
    Phil

  10. #10
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    Can't see why you can't have it idle at say 750?
    But a cam like like will be happier at 800-850.
    Gary
    Regards, Gary

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