Allright guys, this is kinda off the wall, and if it's in the wrong section, please feel free to move it. I wasn't sure. Anyway.


Doin a SBC swap on my roomate's 91 Sonoma. Fuel Delivery question. What I want to do is use the stock in tank pump. I think if I ran a tee fitting with the preasure on one side and the return line on the other, I can do this. I'm gonna have to run a regulator on the pressure side before the carb. So, the two things that have me hung up:

1) Does anyone know the return flow rate/press. on the TBI fuel pumps

2) Does anyone see anything wrong with this idea?

I know this really doesn't apply to fullsize's, but it's for a V8 and I don't think it really goes in the midsize section. TIA for any input.

Rob

 

if you havent found out i can get some numbers for ya after the new year.

 

TBI's run about 14-15 psi. You would need to drop that to about 5-6 psi for a carb. Carb need to be before the regulator since a carb doesn't "flow though". Basically you need to make a loop with the fuel system and t'ed into it before the regulator.

 

Just buy a regulator for a return system. May cost you around $100 or so for a nice one. Just pick up a Jegs or Summit etc... any will have a few to choose from. I fine tuned my own home-made orfice when I did this same thing before. Used a tee and pushed an orfice into the rubber line that I drilled a little at a time to get the right pressure, 4-6psi. This isn't the best way though because of change in demand due to power being applied. A regulator with a spring would work best.

 

That's exactly what I'm talking about. Thanks for the preasure no's. Is that on the return side too, and is it a requirement?

 

There is no pressure on the return side of the reg, it's just flowing back to the tank with no restriction. All the pressure is before the reg. Glad I could help.

 

We put a carbed Vortec 305 in the '94 WT back in 1998. I used a regular old holley carb type regulator that has an inlet and 2 outlets. I ran the supply line coming from the stock in tank pump to the inlet on the reg and then one of the outlets to the carb and the other to the stock return line. I set the pressure to 6 psi and we put 80,000 miles on it with that setup.


A return style regulator like mj mentioned is probably a better way to go, but my setup worked with no problems for me.

 

Im planning on swapping out my tbi on my 90 sierra for a carb. Im going to use the stock intank pump witha mallary bypass style fuel pressure regulator. I have read about several people not using a regulator with a return line with the stock pump and it only last a few minutes/hours.