Old Country
Well-Known Member
Here's my situation, the problem or question will become obvious very quickly:
I've just replaced my entire fuel line system (5/16" to 3/8"), from tank to engine compartment using 3/8" (0.375") outside diameter hardline. Pump is a new Mallory Comp 140, great flow, MUCH more then I should need, to a Mallory Comp Filter to a Holley By-Pass regulator to a fuel block divided 3-ways to my six-pack carb setup (which I've pictured in here a few months back). Simply for looks and the fact that I had them laying in a spare parts box (came with the car project), I'm going to use -6 (3/8") steel braided hoses (Summit brand) with their respective fittings in the engine compartment. Wanting to ensure I maintain as closely as possible the superior-flow of the new larger 3/8" lines, I examined (not sure why) the steel braided hose -6 fitting outlet ID ....and THAT's where I hit the wisdom-wall.
Let's see....
1) 3/8" ID steel braided hose
2) Blue -6 (3/8") fitting screwed into a red hose-nut fitting
3) Remove said -6 from red hose-nut fitting
4) The blue -6 fitting which screws into the red hose-nut has a long/tapered extention which threads/pushes/wedges its way down into the 3/8" ID hose.
5) Holy-Shite: I found that the fitting inlet hole ID and the entire length of the tapered extention is only 0.011" shy of 5/16" .... !!!! Very noticeably smaller than the -6 outlet end of the same fitting!!!! :banghead:
I'm completely and totally stunned that this is a purposely designed major flow restriction... and if that's true... "what the heck!!"...what use is it having 3/8" lines? (actually my 3/8" hardline has an ID of approx .309").:dontknow:
With the way I've designed the fuel system, I'll have several 5/16" restrictions due to these fittigs within my 3/8" system, and at every one of them the fuel pressure will drop, due to the fluid pressure vs fluid flow velocity principle at a flow restriction. You needn't be an Engineer of fluid dynamics to grasp what a compounded flow restrition this creates! :angry5:
SO - to maintain my 3/8" flow advantage, do I have to use 1/2" hose and -8 fittings? Why is this not clearly noted anywhere this sort of hose & fitting stuff is sold? Is it this way for aaaaall of thes fitting or is this a Summit racing el-cheapo brand design FLAW...? I had Russels on my old drag car 20 yrs ago and I don't recall them being like this.
HELP this dumby understand what the hell I just stumbled in to.:angryfir:
I've just replaced my entire fuel line system (5/16" to 3/8"), from tank to engine compartment using 3/8" (0.375") outside diameter hardline. Pump is a new Mallory Comp 140, great flow, MUCH more then I should need, to a Mallory Comp Filter to a Holley By-Pass regulator to a fuel block divided 3-ways to my six-pack carb setup (which I've pictured in here a few months back). Simply for looks and the fact that I had them laying in a spare parts box (came with the car project), I'm going to use -6 (3/8") steel braided hoses (Summit brand) with their respective fittings in the engine compartment. Wanting to ensure I maintain as closely as possible the superior-flow of the new larger 3/8" lines, I examined (not sure why) the steel braided hose -6 fitting outlet ID ....and THAT's where I hit the wisdom-wall.
Let's see....
1) 3/8" ID steel braided hose
2) Blue -6 (3/8") fitting screwed into a red hose-nut fitting
3) Remove said -6 from red hose-nut fitting
4) The blue -6 fitting which screws into the red hose-nut has a long/tapered extention which threads/pushes/wedges its way down into the 3/8" ID hose.
5) Holy-Shite: I found that the fitting inlet hole ID and the entire length of the tapered extention is only 0.011" shy of 5/16" .... !!!! Very noticeably smaller than the -6 outlet end of the same fitting!!!! :banghead:
I'm completely and totally stunned that this is a purposely designed major flow restriction... and if that's true... "what the heck!!"...what use is it having 3/8" lines? (actually my 3/8" hardline has an ID of approx .309").:dontknow:
With the way I've designed the fuel system, I'll have several 5/16" restrictions due to these fittigs within my 3/8" system, and at every one of them the fuel pressure will drop, due to the fluid pressure vs fluid flow velocity principle at a flow restriction. You needn't be an Engineer of fluid dynamics to grasp what a compounded flow restrition this creates! :angry5:
SO - to maintain my 3/8" flow advantage, do I have to use 1/2" hose and -8 fittings? Why is this not clearly noted anywhere this sort of hose & fitting stuff is sold? Is it this way for aaaaall of thes fitting or is this a Summit racing el-cheapo brand design FLAW...? I had Russels on my old drag car 20 yrs ago and I don't recall them being like this.
HELP this dumby understand what the hell I just stumbled in to.:angryfir:
