TBI fuel line fitting question

[Nodnarb76]

I'm in the parts buying phase of my LS swap, and now is time to start piecing together my fuel system.
My question is: what size fittings do I get to connect to the OEM hard fuel lines that originally connected to the TBI unit?
Thanks in advance.

[aknovaman]

3/8 feed and 5/16 return. You can use common brass compression fittings from stock lines as the ls1 only runs at 60psi. Make sure fittings are tight and you will be fine. Ne real need for high dollar fittings. I go to salvage yards and cut the stainless and black braided lines off front wheel drive GM vehicles and use them. You can cut off the collars on the GM crimp lines and push EFI hose onto the fitting. Then be sure to use EFI band clamps as they are not slotted and don't dig into the outside of the fuel lines.

[Nodnarb76]

Originally Posted by aknovaman

3/8 feed and 5/16 return. You can use common brass compression fittings from stock lines as the ls1 only runs at 60psi. Make sure fittings are tight and you will be fine. Ne real need for high dollar fittings. I go to salvage yards and cut the stainless and black braided lines off front wheel drive GM vehicles and use them. You can cut off the collars on the GM crimp lines and push EFI hose onto the fitting. Then be sure to use EFI band clamps as they are not slotted and don't dig into the outside of the fuel lines.

Thank you for the advise, one more quick question, The OEM hard TBI fuel lines that connect to the TBI unit, looks like they will sit right in the middle of the LQ4 intake manifold and won't fit unless I cut/remove them, can you/anyone confirm?

[foamypirate]

Originally Posted by Nodnarb76

Thank you for the advise, one more quick question, The OEM hard TBI fuel lines that connect to the TBI unit, looks like they will sit right in the middle of the LQ4 intake manifold and won't fit unless I cut/remove them, can you/anyone confirm?

I would ditch the entire TBI line from where it attaches to the frame hardline, to engine, and adapt new PTFE lined AN hose at the frame rail connection. I believe the fitting on the factory line is a 16x1.5mm o-ring for the feed, and 14x1.5mm o-ring for the return.

Looks like these fittings would work for adapting to -6AN.

http://www.summitracing.com/parts/rus-640830
http://www.summitracing.com/parts/rus-640820

[aknovaman]

There is nothing wrong with the factory line and its fully capable of supplying plenty of fuel for your application. I dont recommend spending $$ unless its necessary. Cut the o ring ends and attach braided hoses from any gm front wheel drive car. Cost is less than $10 from u wrench it.

[foamypirate]

Originally Posted by aknovaman

There is nothing wrong with the factory line and its fully capable of supplying plenty of fuel for your application. I dont recommend spending $$ unless its necessary. Cut the o ring ends and attach braided hoses from any gm front wheel drive car. Cost is less than $10 from u wrench it.

I just prefer a single one piece line with fewer leak paths. Takes a bit more money to do that, but any time you add a joint or union, it's a possible failure/leak point, something I try to avoid, especially on a fuel system.

To each their own.

[aknovaman]

How does your configuration have less connection points than the single one at the firewall as i suggested?

[foamypirate]

Originally Posted by aknovaman

There is nothing wrong with the factory line and its fully capable of supplying plenty of fuel for your application. I dont recommend spending $$ unless its necessary. Cut the o ring ends and attach braided hoses from any gm front wheel drive car. Cost is less than $10 from u wrench it.

Originally Posted by aknovaman

How does your configuration have less connection points than the single one at the firewall as i suggested?

I was thinking about the TBI unit end of the fuel lines when you said to cut the o-ring fittings off to attach the braided line, not the o-ring fittings on the frame. That would have made it 3 connections. If you are cutting them off at the frame and using the FWD line, then you are correct, that would be 2 connections (fuel rail and hardline). Would you just use fuel injection hose clamps to attach the FWD braided hose to the hardline?

[Nodnarb76]

Originally Posted by foamypirate

I would ditch the entire TBI line from where it attaches to the frame hardline, to engine, and adapt new PTFE lined AN hose at the frame rail connection. I believe the fitting on the factory line is a 16x1.5mm o-ring for the feed, and 14x1.5mm o-ring for the return.

Looks like these fittings would work for adapting to -6AN.

http://www.summitracing.com/parts/rus-640830
http://www.summitracing.com/parts/rus-640820

I have already ordered those two fittings from Summit, I was planning on using those to attach my existing TBI lines that normally go into the TBI unit to the Corvette regulator/filter combo, but now thinking I might just use those fittings to connect to the sending unit/pump and go from there.
Don't want to try and cut/modify existing fuel line as I have never done so before. I would rather spend a little more $ and replace with braided 6AN hose and not be worried about whether I did a good job or not on modifying existing line.