Need to get some opinions here.

I have two Walbro 450s in a stock 2000 bucket and fuel tank with stock feed lines, rails and regulator. The second 450 is wired to turn on at 3 psi by my Eboost controller. Problem is, I don't seem to be getting any added fuel at WOT. My guess is I hit the limit of the stock fuel line diameter or fuel filter. I know the 2nd pump is turning on because at part throttle boost (i.e. in 4th on the highway) it's going pig rich due to the small stock regulator.

The question I have is, do you think I would still be limited if I ran the fuel out the stock feed from the fuel bucket to then -8 or -10 AN lines to aftermarket fuel rails? If the answer to this is yes, then the next step would be a fuel cell with external pump and quit trying to bandaid the stock fuel tank setup.

 

Do you have a fuel pressure gauge? Before doing anything i would get one and see what the pressure is actually doing.

 

No, all I run is a wideband. It's a reasonable idea I suppose, but I'm not sure it will change anything ultimately, unless you think this is a fuel pump problem. I've got 1200 hp worth of fuel pump in the tank (on E85), so I'm thinking it's an issue beyond the tank. It may just be another $100+ thrown in the bucket.

 

I think you would still be restricting it too much. I ended up feeding the pumps together in the bucket to a 10AN line. The 10AN line runs up to the back of the engine, and splits to 2 8AN lines that feed the back of the rails, out the front of the rails to the regulator. I have not had any problems with fueling at all. FWIW I have my 2nd pump turn on at 10PSI.

 

Put a gauge on it and see. Test each pump seperately and together.

 

Wire a dummy lite to the power feed on the second pump. All the cool kids have one. I wonder if your second pump is dropping back off. I have 2 small walbos on stock lines and run E30 at 15psi with 30 gph meth everyday.

 

I have a similar set up with stock regulator and 2 450s with one coming on at 4 psi. With a pressure gauge I can watch the gauge jump when the second pump comes on. I have AN line ran to stock rail and my stock feed as a return, I am E85 also.

 

Your sig says 2004 model. So your truck originally came returnless style, correct. Are you saying you're using the stock in-tank fuel regulator?

 

could it be your factory regulator? the factory lines are 10mm (3/8ths)right?