Lately I've noticed that if I brought the car up to about 5k with anything above about 75% throttle and let off the gas completely I get what seems to sound like a really whiney flutter dump. At about 40k km with no mods except a drop in K&N filter, running regular boost with a stock bov I don't think this should happen. Any ideas?

 

The stock DV might be too slow to react. It's possible you have a leak in the vacuum hose or most likely, OEM allows a little flutter in some situations (I noticed this in my previous turbo cars). Not really sure if the RA suffers from the same thing. I changed the DV right away and back when it was stock I can barely hear it!

 

Sounds like a BOV issue.
I would recommend getting a EVO X (or IX) BOV. Cheap and you will need one anyway in the future when you get tuned.

If you want a stock BOV - let me know - $5+ shipping.

 

Only $5 + shipping??? I'll take 10 of those!

 

Thanks, I've been looking around for a used evo x BOV but still no luck. Hopefully I'll find one soon.