Demon idle question
Thread Starter
Melting Slicks
Joined: Mar 2004
Posts: 3,472
Likes: 18
From: Lake Ozark, MO
Demon idle question
BB 454 with new comp XE274 cam - Mighty Demon 750.
I have the idle transfer screws set at 20 thousands as described in the book. If i leave the screws set at 20 thousands, I cannot get the car to idle high enough by just adding in more timing. I can set the car to idle by adjusting the transfer screws about 3/8 of a turn each beyond the initial book setting, but is this messing up the carb adjustment or is it ok to use them? Book doesn't really say.
I have the idle transfer screws set at 20 thousands as described in the book. If i leave the screws set at 20 thousands, I cannot get the car to idle high enough by just adding in more timing. I can set the car to idle by adjusting the transfer screws about 3/8 of a turn each beyond the initial book setting, but is this messing up the carb adjustment or is it ok to use them? Book doesn't really say.
Heel & Toe
Joined: Nov 2005
Posts: 22
Likes: 0
From: Eagle Grove IA
Mighty Demon
Does your Demond have Idle Ez? If so you may get the idle rpm from there. If not from what I have heard you can adjust from the idle screw as long as you keep primarys and secondairs equal. I wish my Idle Ez worked a little better but I can adjust the idle some from there.
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
the 20 is just a starting point.....you can adjust these both to get the proper idle.....then adjust the a/f screws and go back and do a final adjustment to both the transfer slots
Tech Contributor
Joined: Aug 1999
Posts: 14,379
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
That's correct. The .020" is a starting and reference point to get you in the ballpark and to assure that both primary and secondary idle speeds have the same starting point. Adjust both idle mixture screws evenly from this point. If you get too far out of whack on the .020" (excessive amount of slot exposed) you can get into an off-idle stumble problem, but you need to be more than a full turn on both screws beyond the .020 before you get into that situation. Leave the IdleEZ closed if you can and set up your timing for 36 total and target around 18-22 initial.
