EFI Return Line Size? - Team Camaro Tech
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post #1 of 8 (permalink) Old Dec 20th, 10, 11:59 AM Thread Starter
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Mark
 
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EFI Return Line Size?

Iím considering a FAST EZ EFI system for my winter project, and was wondering what size return line I should use with this unit. My car is plumbed with the stock 3/8 fuel line, and a 1/4 return line. The return line is not being used. Could I use the 1/4 line for the return line to the tank, or should it be 3/8?

69 RS, Hugger orange/black, Deluxe interior, Sony AM/FM/XM/CD, PS & PB. 355, forged pistons, Eagle rods, balanced, Iron Eagles, 9.4:1 CR, .038 quench, XR270HR Cam, Z28 intake, FAST-EZ EFI 2.0, Thorley Tri-Ys, TCI 700R4, 2400 stall, 3.42 posi
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post #2 of 8 (permalink) Old Dec 20th, 10, 12:30 PM
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John
 
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Re: EFI Return Line Size?

The 1/4 should work. check with the fast??
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post #3 of 8 (permalink) Old Dec 20th, 10, 06:13 PM
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wayne
 
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Re: EFI Return Line Size?

I agree...Check with supplier of EFI unit.
I am soon to plumb my unit and it calls for 5/16 minimum (Holley unit)
From what I have read the return line size is very important !
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post #4 of 8 (permalink) Old Dec 21st, 10, 05:55 AM
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Steiner
 
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Re: EFI Return Line Size?

I used this website and decided to use my 3/8" hard line as the return and ran a new -6AN line as the supply. The regulator will be bypassing almost all the fuel at idle.


http://www.centuryperformance.com/fu...e-spg-140.html

If you use a return-style regulator, you will also need a return line from the regulator back to the tank. The size of the return line is dependent on the size of the pump you are using, regardless of the engine's horsepower output. The return line must have limited or NO pressure in it. In most cases, the minimum return line size will match that of the supply line, but a larger return line is sometimes preferred.

Use these ratings to decide your return line sizing based upon fuel pump output:
*Up to 45 GPH = 5/16" or -04 AN
*Up to 90 GPH = 3/8" or -06 AN
*Up to 250 GPH = 1/2" or -08 AN
*Up to 450 GPH = 5/8" or -10 AN
*Up to 900 GPH = 3/4"or -12 AN

'69 Camaro
Dart 400-AFR 195-224/224 HR-Powerjection III TB with F.A.S.T. Sportsman XFI
TKO 600-Moser 3.42-Detroit Truetrac
500hp/538lbft

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'69 Camaro Beater-SFT 327-M20-Moser 4.10-sold
'02 Z/28 vert-stock-sold and totaled
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post #5 of 8 (permalink) Old Dec 21st, 10, 12:47 PM Thread Starter
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Mark
 
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Re: EFI Return Line Size?

Thanks for the input guys. I emailed FAST yesterday and haven't heard from them yet - I'd guess they're short staffed this week due to the holidays. I'll post their reply when I receive it.

69 RS, Hugger orange/black, Deluxe interior, Sony AM/FM/XM/CD, PS & PB. 355, forged pistons, Eagle rods, balanced, Iron Eagles, 9.4:1 CR, .038 quench, XR270HR Cam, Z28 intake, FAST-EZ EFI 2.0, Thorley Tri-Ys, TCI 700R4, 2400 stall, 3.42 posi
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post #6 of 8 (permalink) Old Dec 28th, 10, 12:00 PM
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Fred
 
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Re: EFI Return Line Size?

Mark, You've probably gotten the info you need by now. I just wanted to mention that this regulator from Aeromotove has a pinhole inside of it for the fuel return. It's about the size of a very large carb jet. A 5/16th line should work just fine.

One owner 69 Camaro,(yep, bought it new
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RS SS Hugger Orange, L88, 4:10's tru-tack posi, ducted hood, Endura, spoilers.
TH400 (CX) with Coan 8" converter, GV-OD, 8 track still on console and best et 10.495,
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post #7 of 8 (permalink) Old Dec 28th, 10, 07:25 PM
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Patrick
 
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Re: EFI Return Line Size?

The return on my stock Spectra EFI tank is 5/16

1968 Convertible L92 VVT project, Hotchkiss lowering front & rear.

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post #8 of 8 (permalink) Old Dec 30th, 10, 02:52 PM Thread Starter
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Mark
 
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Re: EFI Return Line Size?

Thanks guys - FAST recommended a 5/16 inch return line. Maybe I'll use the 1/4 inch hard line to vent the tank.

69 RS, Hugger orange/black, Deluxe interior, Sony AM/FM/XM/CD, PS & PB. 355, forged pistons, Eagle rods, balanced, Iron Eagles, 9.4:1 CR, .038 quench, XR270HR Cam, Z28 intake, FAST-EZ EFI 2.0, Thorley Tri-Ys, TCI 700R4, 2400 stall, 3.42 posi
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