Idle speed

Discussion in 'Fuel and Air Systems' started by 69fastbackfish, Jul 28, 2018.

  1. 69fastbackfish

    69fastbackfish Well-Known Member

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    98AA1DBD-1429-4505-9ED7-EDECCA5E74F9.jpeg how do I know what my idle speed target should be on a 383 .30 over rpm performer intake, edelbrock1411 carb, summit cam, tti headers
     
  2. Steven190

    Steven190 FABO Gold Member FABO Gold Member

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    Range should be 750 to 1000 rpm most of the time. Set it to where it will keep an idle speed, drive it and if it stays there, then that is where it needs to be. If it dies when you stop, then increase the speed some.
     
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    • kowalski440

      kowalski440 Well-Known Member

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      Ehrenberg from Mopar action recommends no less than 800 rpm extended idle time for flat tappet cams due to less oil splashing below that. I assume that's an in gear number.
       
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      • TrailBeast

        TrailBeast Slightly Twisted Member

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        I set my idle mixture and speed both by how I like the sound of the idle.
        That just happens to be 800 rpm and about 15.8-16.5 afr.
         
      • AJ/FormS

        AJ/FormS 367 FormS clone 3.09-1.92-1.40-1.09-.78od 3.55s

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        I have a stick
        with a HFT cam
        Neutral idle is 700 with a 230* cam(276/286/110 advertised) and 175psi cylinder pressure, at 14* idle timing.
        Your results are guaranteed to be different.

        That 6400 cam has advertised specs of 288/298/112,with 69* overlap, and a 72* or so ICA, and with iron heads at 10.5Scr, and only a 3.35 stroke, you're in for a bit of fun.
        Get the T-port synced up and Shoot for 800 if it don't try to tear the mounts off when you put it into gear. Then try to ease the timing back while simultaneously working on the low speed system, to get the idle down to a point where you only experience a drop of about 100rpm or less, going into gear.
        I like 600/650 with my 230* cam; it sounds tuff. But I bow to the camshafts need for splash, even tho I modded my valley to piss oil all over the lobes. So sometimes I idle it down to 550 in first gear, and let her idle around the parking lot, pretending we're tuff.
        You may have to reduce your idle timing to get what you want. In which case I would run a two-stage timing curve . Stage one slams the timing back to normal by 2800, and stage two slows it down for maybe another 6 or so degrees, coming in after 3200.
        Happy HotRodding
         
        Last edited: Jul 28, 2018
      • MOPAROFFICIAL

        MOPAROFFICIAL Well-Known Member

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        800-850 rpm sounds good.