Hey all,

So to start im running a returnless fuel system in a cateye 2500hd. Engine is rebuilt Lq4 w/flatttops, ported 317's, 216/220 Elgin, 50lb Flex fuel injectors(from 2010+ trucks i believe), and CAI. Has 20k miles on it.

I Noticed truck felt like it was down on power. Checked fuel pressure at idle..58lbs, when checked with key on it went to 55lbs and dropped to 40lbs in about 5 min. Checked injectors for leaks..none. So im guessing checkvalve. Also the fuelpump has 300K on it and has in tank filter im sure its time to swap out.

Now since motor isnt stock and im planning on going for a bit more hp this winter(maybe 550-600 whp nothing crazy) and also wanting to do e85.. ( the plan is to do a single gt45 with low boost)i want to go with a walboro pump now instead of replacing with stock. Was told a walboro 450 would be ideal for this.

My question is if i go ahead with walboro now with my current setup will it negatively affect my engine in any way as far as performance..in other words is it too much pump for the current setup im running? Would i be better suited to just do a stock replacement and do the 450 later? Also like i said above i am running a return style rail but if need dictates i have returnless rail i can put on.

 

At that 550hp goal.. i would guess you could probably get away with a single walbro 525lph.
If youve got the return style rails, adding a FPR would be ideal.

 

Do the new pump you will be fine. Run a boost referenced regulator and tune the injectors for the new regulator. As long as the injectors are tuned for the regulator and set the regulator at 58 psi you will be fine.

 

Thanks..So until i go FI will i be able to run the 450 for now? In other words while im still NA/returnless will i be able to run it off the stock intank regulator without tuning it? Blackbear tuned my current setup and i would rather not have to go thru the hassle of emailing and getting a new pcm shipped just for a pump. I know Justin is a busy guy and i dont want to bother him with something so trivial ecspecially when i can just get a stock pump to run until wintertime. This winter im getting hptuners because i know once i go FI im gonna want to tune my own truck. Until then id like something i can just drop in and go without needing to tune.

Edit: ok so i just did some digging and im pretty sure thats not feasible..Saw one guy did it on here but his fuel pressure spiked to 66psi..reckon i will just stick with a new stock pump until this winter and do everything at one time.

 

Many have run the pump with stock regulator and no issues. Some have had it over power the stock regulator and had issues with too much pressure. I would just do a Stock pump and do the new pump and fpr at the same time. Less of a headache