I've scoured the web and this forum and can't find a good answer.

This is for a 99-02 LQ4 with the factory return style fuel rails.

1. What RWHP is a stock LQ4 FPR good for? I'd prefer personal, actual results.
2. I'm adding a procharger to my C10. Even if the answer to question #1 is higher than my goal, I think I'd feel better about a boost referenced, aftermarket FPR. The simplest way to do this (that I can think of) is to simply block the return line on the factory fuel rail, and plumb in my boost referenced FPR to the supply line. I have the same setup on my GTO with a Maggie. The return line will simply run out of the new FPR and back to tank. Any reason this won't work? The return line isn't needed to feed fuel to the drivers side rail, correct? I think fuel fills the rail first, then exits thru the FPR and out the return line, but I'm not 100%.

The truck is a cam only LQ4 and currently makes 350 RWHP N/A, 450 RWHP with a 100 shot of nitrous. I'm adding a P1SC and shooting for 12psi. I'd like to keep the nitrous and am estimating about 600 RWHP, hence the FPR question. I don't think I'd trust the factory FPR, even though it's vacuum (and therefore boost?) referenced.

Thanks in advance for any advice.

https://ls1tech.com/forums/conversio...0-lq4-t56.html

-Jeff

 

I've seen people block them, but I'm not a fan of it. Do it the correct way and get a return less rail, the junk yards are full of them. Blocking it sounds like a plan for disaster if whatever you plug it with leaks or blows off....

 

Do you know if the later (post '05?) return less rails are a direct swap?

 

This looks like a really nice solution. I might pull the trigger on it. I just have a couple questions to ask first.

https://www.ebay.com/itm/Z921-Fuel-R...-A9z:rk:1:pf:0

 

Yes they're the same. Only difference is if you have flex fuel injectors or not.