914 with Carbs, Suggestions for the return fuel line Options

[porkchopexpress]

I am getting ready to button up my fuel system after pulling the tank for cleaning and replacing the soft lines.

I have a 72 that a PO carb converted. The return line is capped off back in the engine bay past the plastic fuel line, which seems a bit foolish to plug the line so far back.

Does anyone have a solution for capping the line at the tank? I do evenaually want to change back to FI so I don't want a solution that is permanant.

[yeahmag]

That's how I did mine so in the event I needed to run a bypass style fuel pressure regulator I was good to go. Or go back to FI for that matter...

[monkeyboy]

You could pull the tank and cap it off there with a piece of hose end. That's what I did.

When I go to FI, I will need to install a new pump, so the tank will come out anyway.

[SirAndy]

Why not use it? Even with carbs you'd benefit from circulating the fuel ...
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[zeezee]

Why not use it? Even with carbs you'd benefit from circulating the fuel ...
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[Woody]

Why not use it? Even with carbs you'd benefit from circulating the fuel ...
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I disagree, recirculating the fuel heats it up. Cool fuel atomizes better. I also believe most manufacturers have gone with returnless systems for that same reason.

[SirAndy]

Why not use it? Even with carbs you'd benefit from circulating the fuel ...
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I disagree, recirculating the fuel heats it up. Cool fuel atomizes better. I also believe most manufacturers have gone with returnless systems for that same reason.

If you ever had fuel boil in the carb bowls from heat-soak, you'd know that the tank is a much better heat sink than them tiny bowls.
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[larryM]

just cap it at the tank

it is absolutely stupid to think of any need for recirculating fuel in a carb system with a pressure regulated pump (as are 99.9% of all carb-car fuel puump systems)

- just install a simple psi regulator at 2-3 psi before the carbs, , and the simple fuel pump (like a Facet) will just stop sending more fuel

- no need to run it back to the tank - that's just dumb!

caveat - - some oem early german 911/914-6 fuel pumps DID have a provision for pressure relief via a 3rd pipe

- but a Facet does not require this - go buy a facet pump

.

I am getting ready to button up my fuel system after pulling the tank for cleaning and replacing the soft lines.

I have a 72 that a PO carb converted. The return line is capped off back in the engine bay past the plastic fuel line, which seems a bit foolish to plug the line so far back.

Does anyone have a solution for capping the line at the tank? I do evenaually want to change back to FI so I don't want a solution that is permanant.

[timothy_nd28]

These pics are from my friends car (porkchopexpress). This is his return line situation, the next pic shows where his pump is located.

[DBCooper]

If you ever had fuel boil in the carb bowls from heat-soak, you'd know that the tank is a much better heat sink than them tiny bowls.
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Once fuel gets into the bowls the only place it's going is through the jets. There's no use for a return with carbs.

[brant]

just cap it at the tank

it is absolutely stupid to think of any need for recirculating fuel in a carb system with a pressure regulated pump (as are 99.9% of all carb-car fuel puump systems)

- just install a simple psi regulator at 2-3 psi before the carbs, , and the simple fuel pump (like a Facet) will just stop sending more fuel

- no need to run it back to the tank - that's just dumb!

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I disagree
a re-circulatory system keeps fuel cooler
(the fuel isn't sitting in the lines over the engine absorbing heat)
makes more horsepower as a result
and is better over all (even combats vapor lock)

putting fresh cool fuel into the carb bowl (versus fuel sitting in the line heat soaking above the engine) Does help combat bowl boiling.

all modern cars (and even porsche when it designed the 914) use recirculatory systems. They are used on millions of factory designed current vehicles
even on carbs it is still better than non circulatulatory systems

it is better
only a little better
but still better

not accurate to call a superior design stupid or dumb...

brant

[SirAndy]

If you ever had fuel boil in the carb bowls from heat-soak, you'd know that the tank is a much better heat sink than them tiny bowls.
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Once fuel gets into the bowls the only place it's going is through the jets. There's no use for a return with carbs.

Last i checked there is usually a fuel line connected to that carb ...
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[rhodyguy]

short piece of line on the tank fuel return tube, a tight fit shouldered bolt and a stock clamp.

tim, that fully threaded bolt return line plug is sketchy and if it should leak in the engine compartment...FIRE!! find another place to locate the pump too. hot confines. i try to keep the # of hose connections to a minimum in the engine compartment

edit: something else i noticed. it looks like the pump to carb line runs across the front of the engine to the dr side carb? then all the way back across to the pass side? does the fuel line contact the engine or tin anywhere? if so, try to configure it to keep the footage of the line in the engine compartment to a minimum and off all warm surfaces.
k

[bozo914]

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[monkeyboy]

Mine is done similiar to that, but I plugged the return line at the tank, not all the way at the firewall. I then capped off both ends of the return through the tunnel with vaccuum caps.

My pump is under my tank as well.. Ditch the Facet and get a rotary pump. Much less noisy.

[Woody]

Why not use it? Even with carbs you'd benefit from circulating the fuel ...
(IMG:style_emoticons/default/popcorn[1].gif)

I disagree, recirculating the fuel heats it up. Cool fuel atomizes better. I also believe most manufacturers have gone with returnless systems for that same reason.

If you ever had fuel boil in the carb bowls from heat-soak, you'd know that the tank is a much better heat sink than them tiny bowls.
(IMG:style_emoticons/default/popcorn[1].gif)

Happens every time in between AX runs in the summer. To combat it I start the car a few minutes before each run and hold it at aboot 1500 rpm. I may give runningva return line a shot and see what happens.

[DBCooper]

If you ever had fuel boil in the carb bowls from heat-soak, you'd know that the tank is a much better heat sink than them tiny bowls.
(IMG:style_emoticons/default/popcorn[1].gif)

Once fuel gets into the bowls the only place it's going is through the jets. There's no use for a return with carbs.

Last i checked there is usually a fuel line connected to that carb ...
(IMG:style_emoticons/default/shades.gif)

Sure, but once the gas goes past the needle valve in the carburetor it isn't coming back out, how could it? Fuel might pick up a little heat in the fuel lines, but how much? But more importantly if you're boiling fuel in the fuel lines in your engine compartment then you have other far more serious problems, because that same boiling air is what's going into your engine through the carburetors and is what's being used to cool the engine. If that air's that hot you aren't far away from losing your engine anyway.

Vapor lock usually happens when you shut off the car and stop air flow, which lets heat travel through metal into the carburetors, or into the fuel pump or regulator when they're in the engine compartment. So put in phenolic spacers. But that shouldn't affect fuel lines, which should be spaced out from any heated metal part of the engine and isolated from heat. If they aren't then that should be corrected anyway.