What does everybody run for fuel pressure for an off-road truck? Is 3-4 psi sufficient?

Since my truck has been pretty dormant for a few years, I pulled the edelbrock carb off to rebuild it. I also ordered the 1465 off-road needle and seats to throw in while I have it apart. I ordered a fuel regulator also to keep the fuel pressure down. Years ago I put one on a truck because my Edelbrock had been flooding my motor with fuel after shutdown. I haven't seemed to have that problem with this one but since I am working on the fuel system, now would be the time to add it. The truck is getting all new aluminum 3/8 fuel line, a new electric pump and a carb rebuild this weekend. I think last time I used a regulator for my mud truck I was only running like 3psi of fuel pressure.

This is what I ordered, but now I am wondering if 4psi is enough:
EDL-1465 OFF-ROAD NEEDLE AND SEATS (2) 1 1Z4758400375474539
UPS: 3-4 bus. days
EDL-1477 REBUILD KIT EDELBROCK CARBS 1 1Z4758400375474539
UPS: 3-4 bus. days
HLY-12-804 FUEL PRESS REG 1-4 PSI 1 1Z4758400375474539

I forgot to get a fuel pressure gauge but I think I can get one locally by the weekend.

 

I run about 8.5....

 

i don't have any dedicated off road rigs. everything i have is regulated to a max 6 psi.

 

I guess I'll try 4psi and see if i end up starving for fuel. This a trail rig mainly, we'll see what happens. Unless someone says that its def not enough

 

From the Edelbrock carb manual - "Avoid extremes in fuel pressure. At IDLE, there should not be any more than 6.0 psi; if the vehicle has
an adjustable fuel-pressure regulator, set it to 5.5 psi. With most fuel pumps the minimum fuel
pressure is encountered at high rpm and WOT. Fuel pressure should not drop below 2.0 psi. If it does,
a fuel pump with more capacity may be required."

 

5.5-6psi as said. Which electric fuel pump did you buy?

 

buncha weak sauce in this thread

 

I didn't actually buy one, but I may have to, there was a blue holley in the truck when I bought it, but it didn't work. I will look into getting a rebuild kit for it. The fuel pump I am going to install is labeled Facet and doesn't have specs on it. I just did a quick search and found that it is made by purolator. It looks like the one listed here:

FACET / PUROLATOR PRO 60SV FEP 60SV FUEL PUMP | eBay

However I am not sure if it is this exact model. The case and stickers look the same but it seems they have different ratings. It was a brand new fuel pump I got for free so i decided to use it. I'll try to determine exactly which version is tomorrow to determine if it is sufficient.

 

Check here www.facet-purolator.com/

 

I use this formula to determine if a fuel pump is "enough" for a given application

HP x BSFC = lbs/hr of fuel

BSFC = .4-.5 for mild builds .6 for race .7-.8 for nitrous and boost
Fuel weighs about 6 1/4lbs per gallon.


Based off the engine specs in your sig:
400 x .5 = 200lbs/hr

200/6.25 = 32gal/hr


Id say this pump is not quite adequate and you definitely need more than 4psi. It looks like a shiney gimic part on the "cool kid rack" at your local autozone. 36gal/hr is most likely free flow capacity of the pump...not the flow under load. The Holley Red would work but IMO a Holley Blue and their adjuable regulator set at 5.5-6psi would be a better choice.

 

Thanks alpha! I will try to get my holley blue working and a different regulator! Fuel issue is moot for now, found a loose pushrod and what apears to be a smashed lifter tonight..... Guess those pushrod s were too long!

 

Since I am trying to get this all done right, I will be running new aluminum fuel line from the the fuel cell in the bed to the barb. Is 3/8" sufficient or should I get a larger diameter?

 

In a side note, I completely disassembled my carb today, I found that the far side of what I will call the "fuel rail" in the cover of the carb was packed with grit and what appeared to be white silicon. I Sure am glad I decided to pull the carb apart. The more I am seeing how much was wrong with this engine, the more I am amazed that it ran at all!

 

I have a formula for fuel line size at home but from experience 3/8 is perfectly fine.

 

i ran 7/16's rubber line last time but now im switching to 8an (1/2) alum lines