I can barely hear mine, even with backseat removed. And I've had three of them already. If you have an exhaust you probably won't even hear it. I have to admit though my car is abnormally loud.

 

A 3" exhaust and with the music turned up you won't hear it. Mine was abnormally loud compared to other ones I've had and ones I've heard. Does anyone know for certain why they tend to be so loud? Not speculations but the actual reason? Maybe our stock lines are so small it is putting to much back pressure on the pump making it howl?

 

Both pumps (in my evo and the DSM) are still quiet after years of service.

 

Ive had silent Wally's and I've had Wally's that scream. In all honesty though you can put sound deadening over it or just turn up your radio. It never particularly bothered me, and I've personally had 3, and been in more than 10 cars that run them. Most are pretty quiet.

 

Mines kind of loud. But with a 3 inch exhaust, you can't really hear it while you're driving. I hear it at idle at lights if the radio is off. Not a big problem. I've only had a passenger mention it once, my ex.
"What is that noise?"
"Fuel pump. "
" Why? "
" Because race car."

 

I'm certain a single 255 is not going to support your goal of a true 530 HP. You'll need to do something other than that pump. More than likely a double system. On a single 255, I ran out of fuel at 468 on E85. This was on an accurate DynoJet.

Also, if the 255 is too loud for you, maybe something other than an Evo is more your speed! I don't know about you but all those car sounds are music to me. A noisy fuel pump is its way of checking and letting you know it's ready to play! Just my opinion...

 

My walbro used to be quiet now it whines when the car is completely warmed up, by the way i started to notice that the whine sometimes is in sync with my idle dipping, whine Becomes less audible when my idling starts to drop to around 600 rpm but not enough to stall the engine, but whine gets louder when idle goes back to 900. Could the idle dip be related to the walbro? Or the other way around? Does this mean that there isnt enough voltage to supply the pump? Sorry for the noob question, by the way im having idling issues pertaining to idle dipping on stoplights. Thanks.