Fuel Pump Relief Valve?

[RubyRed300ZX]

I need to replace the fuel pump. The original pump has a relief valve or pressure regulator on the top of the electric motor (it angles away from the motor at a 45 degree angle). Replacements for this motor with the "valve" are around $200 to $258. Z1 shows it here:

http://www.z1motorsports.com/popup_imag ... imageNum=1

There are Walbro pumps and Bosch and others rated at 255 lph; however, they are without this very special valve. These can be had for below $100. My questions are (1) what the hell is this valve on the top (if it's a pressure relief, why is it needed when under the hood there is a fuel pressure regulator) and (2) anybody running a Walbro pump where this valve is not on the pump, yet without any problems?

[NolimitZ32]

1. I know exactly what you are talking about
2. I have no idea what it is or does
3. I run a walbro 255 with 0 issues.

[RubyRed300ZX]

Yeah, I'm stumped on what it is intended to do. My best guess is that it's like the valve for a water supply line in your home which is to eliminate water knock in the a supply line when the water is shut off. But that's a reach.

Your "no problems" with the Walbro 255 is what i wanted hear. Thanks

[NolimitZ32]

What you are referring to (on a water main) is a knock arrested, and that's actually a good theory but we have a fuel damper for that exact reason so unless its a double-redundancy system I don't see why they would've done that. I have an extra NA pump laying around and another soon to be coming from the chassis donor so I might do some rocket surgery and find out.

[Ace2cool]

Def. post up what you find. I'm curious as to what that little thing is too.