Fuel Return Line mods for bigger pumps

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ckd87gn

New Member
What are the typical methods used, parts etc. to run a larger return fuel line when using your tt340 fuel pump?
 
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ckd87gn

New Member
I should have searched the site before I posted the question. I found where eric had replied that he replaced the line from the regulator back to the tank with -6an line. If anybody else has done this mod to there cars and has something else to add please share. thanks ckd
 
EricM

EricM

Administrator
Staff member
The fitting on the bottom of the regulator came from www.discounthydraulichose.com and is part# 9069-06-14 (90° Elbow, 3/8" Male JIC x M14x1.5 Male Metric Adj. (Steel))

That will allow you to connect a -6 AN female hose to the bottom of the regulator.

The -6 hose is from NOS. I ordered it from Summit Racing, part 15480NOS. 16ft long.

The fitting at the end of the hose is a -6AN Male to 5/16" Barb, which I got from Jegs, part # 027-15635. You could most likely get the hose there also.

Then I bought a short piece of 5/16" efi fuel hose, like a foot long, to connect to the original return line above the rear axle (try to find some J30R9 hose, or J30R10 is even better). Now the problem is, the original return line is 1/4", so the 5/16" hose is a little big. So I put 2 clamps on there to make sure it doesn't leak. I don't really like that idea, but at the time, I could not find a -6AN male to 1/4" barb adapter.

So that's pretty much it: the regulator to -6 adapter, the 16ft -6 hose, and the -6 hose barb adapter. I'm sure there are other ways to do it, but this worked well to get the idle pressure down.
 
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brif

Member
I may be doing this next week. Did you run the new return line in the oem location? Did you remove the old return line?
 
EricM

EricM

Administrator
Staff member
It's pretty close to the stock location. At the front, it comes from the regulator, behind the alternator, over towards the inner fender, and down to the frame. It runs along the frame to the back, then up over the rear end.
For now, I left the original return line in place in case I wanted to go back stock.
 
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Pronto

Member
Do you think Ken's (turbofabricators) return line mods ie; removing saginaw fittings and replacing them with compression JIC fittings would do the trick without having to do a complete line?
 
EricM

EricM

Administrator
Staff member
It's very possible. Those fittings were pretty restrictive, and varied from car to car.
 
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MNwe4

Well-Known Member
Eric, thanks for posting this. Made things simple. Only took about 2 hours to hook everything up and start the car. I used the same fitting on the regulator and the same NOS hose you suggested. However, at the end we went with a AN to NPT fitting and then a NPT to 1/4" barb. Those parts also can from discount hydraulic and I think were cheaper than the Aeromotive barb adapter from Summit. Seems to be working good so far. Just though I'd share my experience.
 
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Pronto

Member
Eric said:
The fitting at the end of the hose is a -6AN Male to 5/16" Barb, which I got from Jegs, part # 027-15635. You could most likely get the hose there also.

Then I bought a short piece of 5/16" efi fuel hose, like a foot long, to connect to the original return line above the rear axle (try to find some J30R9 hose, or J30R10 is even better). Now the problem is, the original return line is 1/4", so the 5/16" hose is a little big. So I put 2 clamps on there to make sure it doesn't leak. I don't really like that idea, but at the time, I could not find a -6AN male to 1/4" barb adapter.
Click to expand...

Eric, you can get a reducing union fitting for 6AN male (3/8") to 4AN male (1/4") and then a short length of 1/4" tubing with an 4AN flare and a slight bubble flare the other end for the hose. A friend of mine has a Mastercool flaring tool and we found AN dies for it. Works fantastic. Ridgid makes an AN flaring too as well. I'm temped to do the whole shabang in 1/2" Cunifer metal lines with AN flares and use the 3/8" line as the return.
 
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pmoore4321

Member
This thread solved a two year problem after installing the Denso "Supra" fuel pump. My fuel pressure would not go below 43 lbs with the vacuum line on or off the regulator. My car idles MUCH better now. Thanks to the folks who posted in this thread.

I used Discount Hydraulic Hose part numbers 9069-06-14, 104-0404C, and 2404-06-04. You will also need about 6" of 1/4" fuel line.

The brass 1/4" hose barb has a 11/64" outlet orifice. This leads me to believe drilling out the stock Saginaw fittings as some have mentioned might be good enough. I am going E85 in the future so the hose upgrade gives me room to grow.







 
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