stocker gas line

[Mike Savelle]

Is a 3/8 line from pump to Qjet big enough , if so what size should the return line be ?

[rboyle]

I ran -12an from the tank to the pump and -10 an from pump to regulator then -8 an to the carb, -10 an return from the pump to the tank for my qjet

[Dave Turner]

IMO Mike, 3/8" is too small to feed one of your fuel hungry SBC's.

I was going to suggest -10AN to the regulator, -8 to the carb and -8 return.

[Coleydog]

Originally Posted by Dave Turner

IMO Mike, 3/8" is too small to feed one of your fuel hungry SBC's.

I was going to suggest -10AN to the regulator, -8 to the carb and -8 return.

Better have a big pump with that size line.
Mike

[Dave Turner]

Originally Posted by Coleydog

Better have a big pump with that size line.
Mike

I do....Aeromotive A1000

[Mike Savelle]

Dave I checked your engine specs and understand why you need that much fuel! I got 390/410 lift 1.94/1.50 valves with a Qjet, and run the same class as you. I was told it cost 2-3 times as much to run a Ford .WOW. I priced the a1000, $550 cdn with tax another WOW. I just retired and we are on a budget ha ha .See you next year, and thanks for the input . Mike

[GTX JOHN]

Our small block stockers run 3/8 hard line and Mallory 140 pumps....Never lose pressure.

Our super stocks run 1/2 hard line and Aeromotive pumps.

Of Course our Thermoquad Bowls are BIG and hold a lot of gas.

[Ed Wright]

Just curious, wondering (surely this has been tested) about the flow rate difference through a given size needle & seat assy (say a .125" or .150" dia orfice in the seat) with various i.d. fuel hoses, all much larger I.d. than the orfice in the needle & seat? A Quadrajet only has one, with a small float bowel for all four jets. I'm guessing the most difficult carb to keep full enough? Kinda seems like if the fuel line/hose I.d. was larger than that one orfice, a larger line would not help. Pretty interesting, thinking how a much larger line would alter the flow rate through the seat orfice.

[GTX JOHN]

Two .110 Needles and Seats on Thermoquad.

Some year ago they shut us off on line for clean up down track.
I forgot to turn fuel pump back on....Staged and ran past 1/8 mile
before I ran out of fuel.

[Tom Broome]

Originally Posted by Ed Wright

Just curious, wondering (surely this has been tested) about the flow rate difference through a given size needle & seat assy (say a .125" or .150" dia orfice in the seat) with various i.d. fuel hoses, all much larger I.d. than the orfice in the needle & seat? A Quadrajet only has one, with a small float bowel for all four jets. I'm guessing the most difficult carb to keep full enough? Kinda seems like if the fuel line/hose I.d. was larger than that one orfice, a larger line would not help. Pretty interesting, thinking how a much larger line would alter the flow rate through the seat orfice.

I worked for an aftermarket manufacturer once upon a time and we did test some different configurations using an orifice attached to a flow meter.
We were attempting to qualify the differences between needle and seat area and fuel pressure with respect to fuel volume. We also tested differing configurations before and after the secondary regulator. It's been so long ago now that I don't recall the specifics of that test, but I do remember a fondness for bypass style systems. It seemed that the less total area that you flowed through needed a bypass to keep the secondary regulator functioning.
If the fuel system was primarily laminar flow like fuel injection, fuel line area and orifice area can be closer than a carbureted system. Since a carburetor is essentially a siphoning device, fuel flow through the boosters and calibration are affected by the level of fuel available in the bowl(s). When the needle(s) open the bowl needs to be refilled as rapidly and smoothly as possible.
If your using alcohol with a carburetor the pump essentially overcomes the regulators ability to control pressure at some engine RPM. The needle and seats are the restrictions but volume is increased with the excess pressure.