-6 fuel return line question

1984 t-type

Murphy's Law
Joined
Jul 11, 2010
Just curious on how you guys who change your return line to a -6 connect it to the sending unit.
 
They have adaptors that adapt your sending unit to -8 and -6
 
Slide over and double clamp

I guess where my confusion is with your suggestion is if the -6 line is larger than the factory line how do you clamp it down securely, and if the inlet at the pump stays the same size as the factory line how does this improve the flow, its still the bottleneck it the system right ?
 
I cut the return line end off of the sending unit. Then soldered on a 5/16" brass single barb fitting. This also eliminates the necked down end of the sending unit return.

At the end of the -6 return line, used a -6 male to 5/16" barbed fitting. Then a piece of rubber 5/16" fuel hose and clamps to connect. Note that a standard -6 female hose end was used on the PTFE return hose.

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So the 5/16 fitting slips over the 1/4 tube ?

Probably, was done so long ago I don't recall if I drilled the fitting to fit. Here is a picture of it:

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I welded in some 90 degree adapter fittings. This one has 2 feeds (2 pumps) and 1 return.
 

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Just curious on how you guys who change your return line to a -6 connect it to the sending unit.

The stock return line is 1/4" which is way smaller than -6 AN, but the line and fittings on the way to the sender will be eliminated, but at the end of the line you still have the 1/4" metal return line into the sender?
 
Nick I think you may be getting at the same thing i was trying to ask, the 1/4'' line into the sender is still the restriction right ? Beatav8 seems like what you did would work best without buying a aftermarket sender
 
The return line at the sender is only 1/4" at the end where the fuel hose connects. The actual tubing is 5/16", by removing the short section that has been necked down to 1/4" that restriction is eliminated. Which is what I did with the fitting shown in the picture. The necked down section has been cut off, so the return is -6 to a 5/16" hose to a 5/16" tube to the bottom of the tank.

I can run both fuel pumps (255 lph) at the same time without running the engine and maintain the proper fuel pressure. Before running a new return setup the pressure would skyrocket with both pumps on.

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I was under the impression that it was 1/4'' all the way through the sender, thanks for that info.
 
I'm probably going to have to run bigger fuel lines this year for my build.
 
Im starting to think I may just run a new -8 feed and use the stock feed as a return with -6 fittings at the ends.
 
Use the vent line for return as it is larger and slide #6 over and double clamp
 

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Im starting to think I may just run a new -8 feed and use the stock feed as a return with -6 fittings at the ends.

If you do this need to run the line on the sender to the bottom of the tank. This way the fuel in the tank isn't aerated as the returned fuel sprays onto the fuel in the tank.

Note how the original return line goes to the bottom, that is why. Just need a short piece of rubber hose (SAE30J10), two clamps and a piece of 3/8" steel tube.

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If you do this need to run the line on the sender to the bottom of the tank. This way the fuel in the tank isn't aerated as the returned fuel sprays onto the fuel in the tank.

Note how the original return line goes to the bottom, that is why. Just need a short piece of rubber hose (SAE30J10), two clamps and a piece of 3/8" steel tube.

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Thanks, I was just reading that in another post.
 
Use the vent line for return as it is larger and slide #6 over and double clamp

This isn't really a good idea. The return line has a restriction in it along with a rollover valve. Once the 1/4" necked down portion is removed from the real return line it is the same 5/16" as the vent line. Minus the restriction, rollover valve, and the lack of returning the fuel to the bottom of the tank of the vent line.

Of course this can be corrected by reworking things, but is it worth the effort?

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