Q-jet experts , couple questions

[Redlight]

What is the minimum clearance you can run from air cleaner base to hood/air cleaner lid?

Not running a choke so is there any advantage removing the tower a'la Holley?

How about epoxy work around the top rim?

Any simple/cheap tricks for improving flow on the primary side?

Oh, it's for a bracket car so the "rules" don't apply.


Thanks

[tj310]

Just wire the choke open goes just as fast, we use a flow thru lid goes just as fast as nothing.
some castings are larger on the primary side eg 454 motorhome
Thanx Trevor
re air cleaner lid k/n style yes. re dime a dozen I buy my Quadrajets by the pound and I think that other co. is bankrupt....again

[Redlight]

Trevor,

The choke blade,rod etc all have been removed and mounting holes filled.

Are you talking about K&N style lid?

[Alan Roehrich]

One of the air cleaner bases with the really big radius will help direct air flow. I don't know that the K&N lid helps that much. It may or may not, depending on the area around the carburetor, and only experimenting will tell you.

You need an inch or so at least between the hood and the vent tube. The Q-Jet is a very sophisticated fuel metering device, and air flow around the bowl vents and the feeds/bleeds is critical, excessive turbulence or a lack of clearance around them can upset the circuits.

The Doug Roe book on Q-Jets is one of the best sources for Q-Jet information and tips. No Q-Jet racer should be without a copy of his own.

[Bob Pagano]

"Oh, it's for a bracket car so the "rules" don't apply."

Why run a Q-jet when Holley carbs are a dime a doz. and simpler to tune.

[Mark Yacavone]

Originally Posted by Bob Pagano

"Oh, it's for a bracket car so the "rules" don't apply."

Why run a Q-jet when Holley carbs are a dime a doz. and simpler to tune.

I was wondering the same thing, Bob.


No, you can't remove the tower on a Q jet without making a mess out of it.

[Lynn A McCarty]

Holley simpler to tune? If you call up Mike Beachy and get the hanger adjusting tool he makes, you can tune the carb with simply changing the hanger once you get close with metering rods and jets. I dont see how you can get any simpler than that?

Power? I have been on at least 6 different dynos. A 800 to 850 Holley loses power on our SSers every time. That includes the expensive flowed boosters and all. The only carb that has ever out HPed the Q-jet is the 1150 with all the max tuned flow boosters and venturi. That was only 7HP.

Why do we use the Holley then? For measurements only with the Super Flow air bonnet. It screws with the vent tubes and the secondary air horn. We have found to relocate the air flow mechanism and relocate it as far away from the carb as possible, then making a custom Q-jet carb bonnet helps. The secondary air horn still doesnt like it.

[Bob Pagano]

Lynn its a bracket car, they dont look at the same things we do, it would still be cheaper to run a holley.

[Lynn A McCarty]

I have bracket guys running Q-jets and the love them. You dont have th carry a bucket full of jets and gaskets everywhere you go. You can get away with substandard fuel delivery with a Holley due to the larger fuel bowls and inlets, but otherwise the Q-jet is pretty damn cheap.

I spent a lot of time with the Q-jet guys in Rochester, NY. You guys wouldnt believe the technology of a Q-jet. They still state that the Q-jet was the closest carb to actual fuel injection ever made.

[Mark Yacavone]

For the record, I wasn't advocating a Holley carb for anything, unless the user's application required a bunch more CFM.
I doubt that's the case here.
More specifically, I'd rather see him cobble and hack up a Holley, rather than a good Q- Jet.