It was a pain in the *** to get the o2 dump off... But it was the gasket. It was not the divorced style!

 

nice, glad it was a simple fix. Regarding the flapper, you can straighten it out if it gets bent anytime, no need to swap it since it is pretty strong.

 

Yea... Now i need to find a gasket.. Like now!

 

^ Call up MAP or JMFab. I've bought (the correct style) stainless o2 dump gasket from both of them I saw this thread and knew it was gasket related hehe.

 

I got my divorced dump gasket from MAP. Very nice piece.

 

Its all fixed... And i had a little fun!

 

http://youtu.be/VFvahQAFujs

 

You can also get one of these .
http://www.maperformance.com/maperfo...og-ss-evo.html

 

Looks like the one i just got.. Lol

 

few years late but I'm having this issue right now in my evo 7 from NZ. I've tightened the preload twice but the noise came back for a third time. I have the STM stainless divorced gasket as well. Did you end up just tightening the preload a lot? I've noticed boost doesn't hit till later compared to when the car was first tuned. Also the loud scream hits later as well. I've started to think it's the flapper itself? Oh and the o2 dump is a shearer brand one, which I bought it from a guy on this forum from the states. Cheers guys.