Hey guys

I'm running a turbo 6.0 with a walbro 455. Base fp is at 43psi but under boost its dropping (even though it's a boost ref fpr). Afr are staying at a steady 11 up to 14psi. Should I investigate further or is some FP drop normal? I was under the impression that my pressure should never go below 43, especially with the boost ref regulator. It triggered my fuel pressure safety at 40psi yesterday.

 

Shouldn't drop technically. I do see a pound or two depending on setup. How far does it drop? Check the filter., pre filter ect.
To be clear , those i see a bit of drop on are not boost ref'd.
Yours should show 43 psi (or whatever your base pressure is) pump on engine off. Then the pressure should drop as vacum pulls against the spring as the engine is running, then under boost you should see the pressure rise 1 for 1. so 43psi base plus 15 pounds of boost should land you at 58-ish plus or minus a pound.
The point of a ref'd reg is to keep the delta pressure accross the injectors as a constant.

 

Yah that totally makes sense. My system is setup to hit the two step if under 80percent or more throttle the fuel pressure drops below 38psi. It dropped right when the car was starting to boost (comes on really fast) and I'm really not sure how much. With the two step safety turned off the car pulls perfect 10.5 afr. Maybe time for a gopro on the gauge? Could my Wally 450 be too small for 630whp?

 

Yes it could be too small, but you're not making 630 wheel as it hits boost I'd guess, so I don't think a 450 Walbro is too small at that point. You have something wrong or not working as it's suppose to.

Can you run the pump and apply air pressure to the regulator with car either running or not running? In ether situation you should see the pressure rise evenly as you supply air pressure f you have a 1:1 regulator.

 

Check the reg and reference line for vacuum /boost leaks. Had the same issue, the adj screw on my Aeromotive was leaking.