Q jet power piston spring

[outlaw]

Not sure but I would think that stocker a with a too light of a spring once it starts regaining vacuum on the top end would start plugging rods back down and lean it out. Lean is mean but so is the parts bill.
Terry

[Mark Yacavone]

Alan, all >

I didn't mean to imply that it was some kind of speed secret to eliminate the primary rods.
I've run the same stocker, both ways,... true foot braking it to about 2800-3000 , and never saw a bit of ET movement, either way.
So, the answer is, once again...It depends.

On a Sportsman bracket car, where two stepping is not allowed, but deep staging is, keeping it clean at about 1500 is a good idea.
As mentioned, there are many ways to go about that. A modern, multi-spark ignition goes a long way here.

Stick shift car? Different world, but I've never seen much difference here either.

Bottom line..Pick your poison , and don't stop till ya get enough :-)

[Alan Roehrich]

Originally Posted by Mark Yacavone

Alan, all >

I didn't mean to imply that it was some kind of speed secret to eliminate the primary rods.
I've run the same stocker, both ways,... true foot braking it to about 2800-3000 , and never saw a bit of ET movement, either way.
So, the answer is, once again...It depends.

On a Sportsman bracket car, where two stepping is not allowed, but deep staging is, keeping it clean at about 1500 is a good idea.
As mentioned, there are many ways to go about that. A modern, multi-spark ignition goes a long way here.

Stick shift car? Different world, but I've never seen much difference here either.

Bottom line..Pick your poison , and don't stop till ya get enough :-)

Oh, by all means, my way is not necessarily the only way, or even the best way. It's what I learned, from 40 years of working on QuadraJets, and from guys like Ashley, Oliver, Bridges, and Schindler.


The QuadraJet is very sophisticated. I suppose for many, eliminating the power enrichment circuit simplifies things. I prefer to use everything it offers.


Your mileage may vary.

[Alan Roehrich]

Originally Posted by outlaw

Not sure but I would think that stocker a with a too light of a spring once it starts regaining vacuum on the top end would start plugging rods back down and lean it out. Lean is mean but so is the parts bill.
Terry

Well, few QuadraJet combinations are capable of moving so much air that a 750 or 800 cfm carburetor will become such a restriction that they generate more than 5"- 8" of vacuum, you MIGHT see that on one of the 454 Super Stock engines. If memory serves correct, the orange power piston spring, for example, will overcome 10" to 12" of vacuum. Remember, most 4 barrel carburetors are rated for cfm at 2.5" of vacuum.