Technical Topics specific to the Hatchback body - NOT where you post pics/build specs of your car.
By noob
#359394 Hi all, done a lot of reading but cannot seem to get a clear answer.

My project eg hatch is coming along nicely and hoping to have the h22 in there within the next few months.

I have installed a brand new fuel tank, new fuel low level sensor, new fuel sender unit with Walbro 255 pump.

I've ran 3 x an -6 stainless steel braided Teflon hoses from the front bulk head all the way to the tank. One for the fuel feed, one for the return and one to the 2 way valve for vapors.

Is this OK? Or will the pump struggle to keep pressure due to the increased hose internal diameter?

I'd appreciate your opinions on the matter, many thanks.
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By Driv-it-hard
#359397 Noob,
I have done some conversion of some lines from standard hard lines to AN braided line. This is only my opinion, I think the line would be a little to wide for fuel flow. On the return doesn't mean anything.
Please everyone, chime on this and lend a helping hand.
I could be wrong as I could be correct.
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By teal_dx
#359402 I don't think so... once the line is full of fuel, it wouldn't make a difference if it was a little wider. The pressure and fuel will still be there. The same amount would still be getting to the fuel filter/fuel rail. I'm not an engineer though, so I'd like to hear some more opinions as well.
But on the other hand... in house plumbing, the pipe dia starts larger (say 3/4") and steps down to 5/8" and then 1/2" by the time it gets to a faucet, so maybe the smaller pipe does help with building pressure. That/s a house and water though, not a car and fuel.
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By Driv-it-hard
#359403
teal_dx wrote:I don't think so... once the line is full of fuel, it wouldn't make a difference if it was a little wider. The pressure and fuel will still be there. The same amount would still be getting to the fuel filter/fuel rail. I'm not an engineer though, so I'd like to hear some more opinions as well.
But on the other hand... in house plumbing, the pipe dia starts larger (say 3/4") and steps down to 5/8" and then 1/2" by the time it gets to a faucet, so maybe the smaller pipe does help with building pressure. That/s a house and water though, not a car and fuel.



Well said... Thank you Teal.
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By TrailerTrash
#359408 Surely a W255 would have no problem keeping that line pressurized. At least thats how i would look at it :?
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By EconoBox
#359416 That pump will have no trouble keeping those lines pressurized. I had the same setup on my old H22 swap. Be sure you run a quality fuel pressure regulator (Aeromotive is what I had) and mount it to the firewall or shock tower not on the motor itself. You don't want that weight hanging from your fuel rail and why subject the regulator to any extra vibration which could shorten the life of the diaphragm inside or lead to leaks.
By noob
#364565 Hi everyone,

I thought I'd write back with the end scenario! I finished my swap and fuel system, the car starts, and runs great. I ended up with the following setup:

Ran -6 AN braided lines from the fuel tank for the fuel feed, return and breather.

Used an AEM fuel rail, with seperate AEM fuel pressure regulator.

Everything worked fine, with the small exception of of one of the 1/8th NPT fittings on the AEM rail would not seal for love nor money, naturally i then sheared the fitting........ to took off the AEM rail taking it to a machine shop to get drilled and tapped.

So ended up using the original fuel rail with stock FPR and ran an 8mm ID hose from the FPR to the braided -6 line on the return, and fitted the -6 AN feed line with a banjo fitting onto the stock rail. Im bolting this all up over the next few days, I'll post a pic up with the end result.

Cheers for your help though guys.