1969 Camaro with a 307.

Can i convert the 1/4 return line into the tank into a pressurized return line?

I will have an electric inline pump on the feed line, going to a throttle body injection unit. Withing the TBI unit, is a fuel pressure regulator right before the return line. The return line for stock tbi systems is 5/16ths. I would like to convert my 1/4 return line into a 14psi return line.

Is that line specifically a vent line, or can it be pressurized like I would like to do. Has anybody done this before?

I just bought a new tank and sending unit, i got the sending unit with the return line hopeing to be able to do this. I will be using -6 braided steel for my feed line, and -4 for my return. Wich is 3/4" for -6 and 1/4" for -4. Im pretty sure those correspond.

Any suggestions or hints that anybody could give would be greatly appreciated. Thanks

The line itself can be pressurized with no problems; actually the return fuel isn't under much pressure. The problem may be in that the diameter isn't large enough to handle the amount of fuel bypassed. If that is the case you won't be able to properly regulate the fuel pressure at idle or low loads as the return fuel will be backing up in the return line and cause the pressure before the regulator to raise.

Since you haven't installed it yet, why not take the sender down to the local fab shop or radiator shop and have them remove and solder in a larger 5/16 or 3/8" nipple. Then you could run #6 line for the return and be guaranteed of no problems.

You could try it. If the fuel pressure at idle stays within specs you should be okay. If it's too high you'll need to run a larger line back to the tank and get a 5/16 or 3/8" nipple put in the sender instead of the 1/4".

Jody

[This message has been edited by Camcojb (edited 06-13-2001).]

well stock tbi systems have 3/8 feed and 5/16 return.

think the small drop in dia. to 1/4 will increase pressure. stock tbi pressure is around 9psi, i will be running a higher pressure anyway.
will i kill my pump?

what do you think.

If I had to guess, I'd say it'll probably work. The reason I threw the other stuff out there is because I've had the small line, pressure too high thing happen to me. That way, if it does cause a problem you'll know where to start instead of trying to figure out why the thing is too rich at idle, etc.

Jody