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Old 08-08-2018, 03:34 PM   #1
michael bustamante
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return fuel line questions

getting ready to plumb the lines.
I have a 5.3 from a 2003 Yukon xl 2wd dbw with the return fuel system.
I know the main line is 3/8 an6 but the return is smaller. 5/16 right?
is there a 5/16 connection at the rail to a 3/8 fuel line or do I need to get 5/16 return line? (PTFE all of course)
also what micron fuel filter should I get. just street, no mods to the engine just yet
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Old 08-08-2018, 04:35 PM   #2
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Re: return fuel line questions

Is there a reason to use PTFE? In any case I used adapters, (2) quick disconnects, at the fuel rails, that convert the fuel lines, the feed line and return line to 6AN. The fuel filter i used, which was 6AN, is 100 microns. Summitracing or the other part houses sells them. good luck on your LSw swap.
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Old 08-08-2018, 04:38 PM   #3
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Re: return fuel line questions

here are some examples of what i sued for my swap. (1) quick disconnet (2) is a 100 micron fuel filter.
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Old 08-08-2018, 04:38 PM   #4
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Re: return fuel line questions

example
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Old 08-08-2018, 04:41 PM   #5
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Re: return fuel line questions

example.
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Old 08-08-2018, 05:13 PM   #6
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Re: return fuel line questions

What are your plans for a pump?
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Old 08-08-2018, 07:19 PM   #7
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Re: return fuel line questions

@mongocanfly I'm going use fuel pump EP381, fuel sending unit FG051M, and either Weld-on Bunges (-6AN) or a Compression fittings to adapt the fuel sending unit to, the -6AN fuel line. I have had great success with this in the past. i also used a jeep(1985-1990) fuel tank. it fits nice, between the frame rails of my 1972 c10.
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Old 08-08-2018, 10:31 PM   #8
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Re: return fuel line questions

PTFE is nice if your wanting to run flex fuel, and realistically "lasts" longer in terms of resistance to breakdown. You pay the price on the fittings tho.
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Old 08-08-2018, 11:42 PM   #9
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Re: return fuel line questions

Not to be a buzz kill but most injector manufacturers want no more than a 10 micron filter.

Also, the quick connects with the plastic lock tab are a known fire hazzard. There have been many many stories of them popping off and starting a fuel fire.
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Old 08-09-2018, 06:59 AM   #10
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Re: return fuel line questions

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Originally Posted by indymachinist View Post
Not to be a buzz kill but most injector manufacturers want no more than a 10 micron filter.

Also, the quick connects with the plastic lock tab are a known fire hazzard. There have been many many stories of them popping off and starting a fuel fire.
I agree about the plastic clip . Get the ones that have the thread . The plastic ones can cause the line to pop out and pump fuel all over .
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Old 08-09-2018, 07:25 AM   #11
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Re: return fuel line questions

What fittings with the threads are you talking about? Do you have a sample pic. The only ones I knew about were the ones that snapped on.
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Old 08-09-2018, 09:19 AM   #12
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Re: return fuel line questions

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Old 08-09-2018, 09:44 AM   #13
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Re: return fuel line questions

Who makes the fitting and the cost ?
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Old 08-09-2018, 09:49 AM   #14
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Re: return fuel line questions

Summit Racing...Russell
https://www.summitracing.com/parts/rus-644123
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Old 08-09-2018, 09:58 AM   #15
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Re: return fuel line questions

Thanks
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Old 08-09-2018, 10:21 AM   #16
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Re: return fuel line questions

Quote:
Originally Posted by rustycars63 View Post
Thanks
you're welcome....they have them in just about any configuration...
that one is just the first one I saw that had the threaded retainer...
there is another style that also has a positive keeper attached to keep it in place...little pricier...
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Old 08-09-2018, 03:45 PM   #17
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Re: return fuel line questions

@indymachinist thanks for the info in reference to the plastic retainer used for the quick disconnect fittings. i may need to rethink some things.
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Old 08-10-2018, 10:26 AM   #18
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Re: return fuel line questions

going to rethink myself. thanks
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Old 08-10-2018, 02:15 PM   #19
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Re: return fuel line questions

dec0... thanks for all the info. I used the same tank and fender and pump unit you did,
all you guys were a great help. ive ordered all my stuff. thank you.
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Old 08-11-2018, 09:19 AM   #20
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Re: return fuel line questions

Whats everyone's thoughts on a filler for the Jeep tanks?
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Old 08-11-2018, 12:12 PM   #21
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Re: return fuel line questions

I've heard it argued that the return line should be as large or larger than the feed line, since it has to carry (at idle, anyway) the same amount of fuel but at lower pressure.

I know on my old '94 LT1 when I put a more powerful pump in, I couldn't keep the pressure down low enough. Turns out the factory return and regulator wasn't sufficient, and I had to upside the regulator.

I'm sure 5/16 would likely be fine. I'm running 3/8 both directions myself.
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Old 08-11-2018, 10:56 PM   #22
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Re: return fuel line questions

@davepl, I don that before. on my latest LSx Swap, I'm using -6AN braided line for the feed line and return line. @Flubyu I can post more pics and info if its ok by michael Bustamante its his thread, I don't want to take over his thread. I can start my own.
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Old 08-11-2018, 11:18 PM   #23
michael bustamante
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Re: return fuel line questions

Dec0 post away buddy. Pics are always good
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Old 09-14-2018, 08:40 PM   #24
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Re: return fuel line questions

Quote:
Originally Posted by dec010974 View Post
@mongocanfly I'm going use fuel pump EP381, fuel sending unit FG051M, and either Weld-on Bunges (-6AN) or a Compression fittings to adapt the fuel sending unit to, the -6AN fuel line. I have had great success with this in the past. i also used a jeep(1985-1990) fuel tank. it fits nice, between the frame rails of my 1972 c10.
What kind of jeep fuel tank, from a wrangler?
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Old 09-17-2018, 01:09 PM   #25
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Re: return fuel line questions

Yes, Wrangler tank (be sure to get a fuel injected version) from a 87-90 Wrangler.
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