Ls Fuel Line Size

Discussion in 'High Tech Retrofits' started by hot72rod, May 20, 2015.

  1. hot72rod

    hot72rod Veteran Member Gold Member

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    Trying to map out my fuel system. I think I know what will work after reading multiple threads on the subject. My car is a 73, I will be using a tank from Spectra. I know from the factory that I have 2 fuel lines running up the passenger side of the car, a 3/8 supply and a 5/16 return. On the driver side there is a 5/16 vent line. I plan to use the vette filter (wix 33737) as my inline filter and use the return line coming off of the filter as my return going back to the tank. So this should eliminate one of the lines going to the front. I'm thinking that the stock 3/8 line should be sufficient.
     
  2. badazz81z28

    badazz81z28 Veteran Member

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    Depends on where you want to mount the vette filter. I personally put it close to the tank on my car. So I had a return line that was about 2 feet long and the primary 3/8" line up to the rails.

    The vent line on the driver side is up to you and the set-up. I eliminated it on mine and ran a vent from Brian Finch (installed in the trunk). II Much Fabrication has one too.
     
  3. 2ndGenJunkie

    2ndGenJunkie Veteran Member

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    You're right on the sizing. Just my opinion, but if i was you, I'd go with a Tanks Inc setup instead of Spectra. I have had a hell of a time with the Spectra GM42AFI tank on my 73. Nothing but problems. If you use the vented version (GM42BFI) you may have better luck, but i wouldnt trust the AFI tank for anything...
     
  4. hot72rod

    hot72rod Veteran Member Gold Member

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    The GM42AFI doesn't have a vent line. I was planning to use a vented cap.

    2ndGenJunkie what kind of problems were you having with the tank? I know if you don't run a vented cap it will cause vapor lock.
     
  5. 2ndGenJunkie

    2ndGenJunkie Veteran Member

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    I have a vented cap but i'm still getting horrible starvation issues while turning if i'm at 1/2 tank or less. At first i thought it was a baffling problem but now i'm wondering if some air pocket is moving around in there because it's a sealed tank. It seems that most people with Spectra tank issues have the AFI tank. Tanks Inc specifically says that a vented cap is not sufficient for an EFI car so all their tanks have a nipple for a vent line. I'll be changing my Spectra tank out for a Tank Inc setup soon. BTW, here's the problem with a vented cap in the first place: If you're accelerating and fuel sloshes back up into the filler neck it can defeat the vent in the cap by covering it with fuel. You need a vent near the FRONT of the tank like the Tanks inc tank or the GM42BFI Spectra tank...
     
    Last edited: May 20, 2015
  6. hot72rod

    hot72rod Veteran Member Gold Member

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    Good to know. What is the price like on the Tanks Inc unit.
     
  7. 2ndGenJunkie

    2ndGenJunkie Veteran Member

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    You can order from different places but from Custom Works (site sponsor) I believe it's around $500
     
  8. Printstron

    Printstron Veteran Member Lifetime Gold Member

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    I just ordered one but haven't received it yet and it was $560 shipped.

    1- GPA-4 High Flow Fuel Pump Module - 255 Liters Per Hour - Up to 630 hp- kt @ $220.00 ($220.00)
    1- TAN-GML Fuel Tank Sending Unit GM 1965 & UP Type 5 Hole Design - 0-90 Ohms @ $35.00 ($35.00)
    1- TM42A-T 1970-73 Camaro / Firebird Fuel Injection Gas Tank @ $255.00 ($255.00)


    $510.00 SubTotal
    $0.00 Sales Tax
    $49.93 Fedex Ground
    ________
    $559.93 TOTAL
     
  9. hot72rod

    hot72rod Veteran Member Gold Member

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    2ndGenJunkie how long have you had the Spectra tank in the car?

    Thanks for the info Prinstron.
     
  10. 2ndGenJunkie

    2ndGenJunkie Veteran Member

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    So with that question, I'm going to assume you think i have their old tank and not a new "redesigned" one. To answer your question, my tank is about 4 years old. BUT I bought a brand new tank from them about a month ago because I believed their claims that they redesigned the tanks and fixed all the problems. After the new one came in, I opened it up and it was IDENTICAL to my 4 year old tank. So I sent it back, lost about $60 in shipping that they wouldnt refund and decided I'd never do business with them again...
     

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