Basically that hole where the brass fitting is feeds down to the bottom of the bucket. There is a plastic elbow that makes the return fuel do a 180 and shoot back up into the bucket. Its on the bottom of the outer bucket. On the piece that makes the return fuel do a 180 where it shoots the fuel back into the bucket there is a fairly small hole and its set a few mm away from the bottom of the bucket. It shoots through a larger hole in the bucket. The concept is that the really high velocity of fuel being shot upward into the bucket through the larger hole draws other fuel in with it.

While you're at it pop the venturi off and make the hole slightly larger. If you don't you will have fuel pressure issues in low load situations. You wont be able to get fuel pressure low enough.

Here's a video Pat posted a while back showing how to remove the piece on the bottom of the bucket. When he holds it up and shows you the piece, the hole you want to make larger is on the top. Drill it out. I forget what I drilled it out to, but it was almost twice the size.

 

Ahhh thanks for the explanation. How big am I drilling out that hole then?

 

Aaand which hole would I be opening up? 1 or 2?

 

#1.

Measure how big it is with a drill bit. It's small. 1/8" maybe. A tad less than double its size will work just fine. There is a small ring around it. Definitely don't go any larger than that ring.

 

Just something else that popped into my head concerning the fuel pressure drop, could cavitation be causing an issue?

 

Another question, the pump and sock are resting on the bottom of the bucket, should that be pulled up a bit off the bottom?

 

Nah I think its fine.

 

New walbro 450 in, and hooked up the factory Venturi/return port. Hopefully I can take it for a quick spin later and see if anything changes.

I'm hoping it was either a pump not keeping up, or it sucking the bucket dry deal and not cavitation, which I have been reading up on that could possibly be the issue too

 

Looks good! I would bet the issues are gone!

 

All is well so far. It's sitting on E and I got no drop in fuel pressure like it was doing before and everything seems to be working properly.

Now I have a silly question, with the BRFP reg, my base pressure is 58, if I add say 12lbs of boost, am I supposed to be seeing 70lbs, or just it holding steady at 58.. I got it to make about 6/7psi and it would just jump to 58/60psi