good over 500 on a double pumper using a hobbs switch. the reason you need the after market FPR is when your setting you base idle pressure, the newly rewired pump will be getting a constant 12-14v overruning the stock FPR. where as with stock wiring the pump gets a lower voltage at idle. correct me if im wrong even when you go into WOT full boost the current stock wiring, even when it switches to use the high voltage setting it doenst even get a full 12v.

if your base idle pressure is off from the beggening then ( the base idle is on a 1:1 ratio starting @ 34psi) when your getting into boost its way off. When i contacted Aaron about a fueling issue i was having he sated that if the FPR is being over ran it causes a LEAN condition. not good at all......

 

https://www.evolutionm.net/forums/ev...gulator-2.html Post #20 by David Buschur.
I just dont see how a rewired drop in 255 or 340 can overrun the stock FPR...

 

I have a FIC rail, Fic 1250 injectors and a Fuel Labs fuel regulator. Without the rewire the pressure looked fine on the same tune as the 255 had. Once I added the rewire the fuel labs reg could not get the pressure down. The fuel couldn't get back to the tank fast enough. This was with the stock hanger.

 

if the pressure was good why did you do the rewire?

 

It's the voltage that overruns the pump, not the pressure. Just get a 400 and don't rewire it.

 

this is because his double pumpers use a HOBS switch.

 

^^ I know that but at full boost it seems the combined pressure of 2 255's would overrun the FPR? Quick question, Is the 400/416 (whichever one is e85 compatible) just a straight drop in?

 

nope you have to modify the fuel hanger, there are a few people who do it though.

http://www.maperformance.com/maperfo...wal400mod.html

look at the pix on the bottom.

 

hmmm and dont rewire it... i may have to see what my 255 can do before I invest in this. My EF3 will be running outta steam a bit over 500hp so it may not be worth the money for the extra 20 or so HP...

 

I RAN INTO A NEW PROBLEM!!!!

Update:
Ok, so firstly there was 2 access points to the fuel tank. I opened the one on the left hand side. It had the stock in-tank fuel pump. I removed it and realized I had to modify the housing to plug up the Walbro 400.

I modified the housing to support the Walbro 400. Everything seemed fine, but when I went to place it in, I realized that the fuel filter attached to the bottom is 1-2 cm's too big.
(About to go buy a smaller one similar to stock size, so problem should be fine I hope).

When I realized it was very small, I looked in the tank and seen it was basically a fuel surge tank. It had no room and was tiny. I decided to open the other one, hoping I didn't remove the wrong pump. Opening it I found no pump, just a filter.

So, my question is:
Is there a in-line fuel pump that is between them, or does the single in-tank fuel pump pull fuel from the other tank?