General Category > Quadrajet Carb Talk and Tips
Idle tuning
77cruiser:
What's the cam?
You really need more initial timing.
How much vacuum do you have at idle?
55 Tony:
No to more initial timing advance. At 8-9 degrees it's hard to start, kicks back and breaks starters.
Idle vac is 15 but the idle is a bit fast at 800.
Cam:
http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=436&sb=0
Previous q-jet idled as low as 500 in gear when good and hot. (17058212 I think?)
77cruiser:
Your vac. adv. is hooked to manifold vac.?
Probably needs to have the idle circuit enlarged to provide more fuel.
Frank400:
Yes, lots more idle fuel with a big roller cam. Most every other circuit will need attention as well, in my opinion.
Also, if that is a healthy roller cam, 800 rpm at idle isn't that fast.
55 Tony:
Yes vacuum advance is to the manifold. I tested every port on the carb and none gave more vacuum than the manifold. The one ported one was about equal but with more of a lag when accelerating. Didn't all cars have vacuum advance to the manifold before smog laws came around?
As in my original post, all other circuits are working perfectly throughout their ranges. No need for changes there, I am working on the idle only.
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