Ok, I got my new CCC Q-Jet on and working very well. Since I'm pretty much an FI guy and I'm not real smart in the carb area I'm gonna ask a dumb question about the secondaries. I guess q-jets are mech secondaries?? Can someone explain to me at what point they open? I noticed that mine dont open when I just give it gas so I poked a small screw driver to see if the bottom throttle plates open and I can budge them, I just figured they opened when the primaries did as the gas peddle was depressed.

 

No the comp controlled Quad is vacume secondaries, and no you will have a hard time opening them up all though you can look in the "How To" section of this site to learn how to fine tune it to open earlier and quicker giving you more power right off the bat

 

If you hold your carb up in the air, and hold down the fast idle cam (and the secondary lockout tab), then rotates the throttle linkage with your other arm, you'll see at about ~65% opening of primary throttle blades your secondary throttle blades start to open.

I thought this meant it's a mechanical secondary carb...

However, yes, the secondary air valve is vacuum operated.


Anyone want to clarify this?

 

And see thats my thing, at 100% of the primary throttle blades being open the 0% of the secondarys are open. What this "lockout tab" and mabey I disengaged it somehow when I was installing the carb??

 

The Quadrajet and the Carter/Edelbrock style carbs have secondary valves which are opened mechanically by throttle action, but they all have an air valve over the secondaries, which makes them behave more like vacuum secondary carbs. "Demand based secondaries" is probably a better term for them.

Hold the choke and secondary air valve open while you open the throttle, you should be able to look down the secondary bores to see the secondary valves opening.