LS bypass fuel pressure regulator question
 

Happy sunday!

Quick question,
I'm working on the fuel system on my swap need a little guidance.

Im working with the bypass fuel pressure regulator...Does it have to be plumbed to the top of the fuel tank or can it be tied back to the suction side of the fuel pump (external fuel pump).

I didn't know if it was purely vapors going back to the gas tank or liquids or a little bit of column a and a little bit of column b.

Thank you,

double.

Re: LS bypass fuel pressure regulator question
 

It needs to be a separate line back into the tank...not the suction side of the pump..
what filter/reg are you using?

Re: LS bypass fuel pressure regulator question
 

I'm using this one.

https://www.jegs.com/i/JEGS/555/14410/10002/-1

I can make it happen to the tank, i just didn't know what was being returned to the tank. IE vapors left over from the rail, or liquid not being used from the rail...or a little bit of both.

Re: LS bypass fuel pressure regulator question
 

it returns unused fuel back to the tank...that filter/reg is similar to the vett unit that ive used...be sure you plumb inlet and return correct..ive seen them hooked up backwards
I assume you have returnless fuel rails?

Re: LS bypass fuel pressure regulator question
 

It needs to be pumped back to the tank.

Re: LS bypass fuel pressure regulator question
 

That is a good question...i was looking the other day to where it pipes back into the tank...I'll double check that in the morning when I get back.

In the event it is an returnless fuel rail, whats a good fuel rail that has a return.

Re: LS bypass fuel pressure regulator question
 

if your gonna use a return rail system you don't need a filter/reg....
the stock rails work just fine
returnless rail will need the filter/reg

Re: LS bypass fuel pressure regulator question
 

that was gonna be my next question, if it the original fuel system on the motor didn't have a return system on it before, why does it need one now? Better yet, why is it beneficial to have a return type fuel system

I have a pre and post filter on my fuel pump, so all i need is a regulator to set my psi going into the rail. Which means i can do away with the bypass regulator , since I'm going to go with the return-less rail system?



Best regards,

double

Re: LS bypass fuel pressure regulator question
 

if you use a returnless rail you must have the regulator

if you use a return style rail you don't need a regulator

not sure what you mean by bypass regulator..unless your talking vett style filter/reg

Re: LS bypass fuel pressure regulator question
 

this is how mine is setup with the vet filter/reg with a returnless rail

Re: LS bypass fuel pressure regulator question
 

this is how a return rail system is setup

Re: LS bypass fuel pressure regulator question
 

What you're suggesting would theoretically work, but is not recommended.

#1, as fuel bypasses the regulator, it heats up. You're looping this hot fuel through the pump again and again, instead of mixing it with cold fuel in the tank.

#2, it would be much more possible to airlock the fuel system when you run out.

Re: LS bypass fuel pressure regulator question
 

Awesome, thank you man...yea im using the vette style reg too.

Did you use the stock fuel tank or get a new one with a return port in it already?

Re: LS bypass fuel pressure regulator question
 

Okay that makes sense, hotter and hotter it would get and the psi would keep raising as well.

Thank you for you knowledge!

Re: LS bypass fuel pressure regulator question
 

im using the stock tank...mine already had a return port on it
remember, the pressure side of the vet filter/reg is the outside port and the center port is the bypass back to the tank

Re: LS bypass fuel pressure regulator question
 

Otays then!

Nows I gotta find a way to fab up a return port for my stock tank then.

I appreciate the help mongo, I really do!!!

double

Re: LS bypass fuel pressure regulator question
 

Not knowing what year truck you have this is what I did to my 65 I used a seconds sending unit and mounted an in tank fuel pump then I used the original fuel line as my return I used the Corvette filter/regulatorAttachment 1910773

Attachment 1910774

Attachment 1910775

Re: LS bypass fuel pressure regulator question
 

[QUOTE=nsb29;8540448]Not knowing what year truck you have this is what I did to my 65 I used a seconds sending unit and mounted an in tank fuel pump then I used the original fuel line as my return I used the Corvette filter/regulator

Wow, I was thinking today of how to use my existing sending unit and it didn't even cross my mind to use a second unit for the return....this is a URIKA moment lol.

I've never mounted an in tank fuel pump before, how difficult is that. I bought an external pump, but after some further research, I'm second guessing it and thinking about an intank pump.

and i have a regular old 1970 c10 long bed

Re: LS bypass fuel pressure regulator question
 

I know several run incab/intank...nsb,dayj1,and others...mines external I've had no issues with it...your tank being in cab you may want to go internal...

Re: LS bypass fuel pressure regulator question
 

It’s a pecs of cake but you have to make a ring to mount on the inside of the tank drill holes and tap threads you can see it cut in half on the bottom of the picture then spot weld it

Re: LS bypass fuel pressure regulator question
 

Sorry for the no response, Hawaii trip changed my whole life lol.

Did you truncate the ends to both sending units or just the one for the fuel pump to mount?

Thanks,
double

Re: LS bypass fuel pressure regulator question
 

I think that's what I'm gonna do....it sounds like the better way to do it.

Re: LS bypass fuel pressure regulator question
 

What would be the harm of just using some quarter twenty stainless steel bolt with a washer, locknut and Loctite on it?

Re: LS bypass fuel pressure regulator question
 

How would you hold them in there??

Re: LS bypass fuel pressure regulator question
 

you sir have a very good point, scratch my pervious question lol.