Get rid of Whoosh sound after K&N Filter

[sharkme2]

Hello,

Recently bought a used 2010 Hyundai Genesis 2.0T Coupe.
The car has a noticeable "Whoosh" sound when releasing the throttle under heavy load. I'm trying to completely get rid of this.
Previous owner mentioned that they had installed a K&N cold air filter and also removed a related component (i think a connector or similar that was upstream).

Could someone please advise on:
1. What is actually causing that whoosh sound ?
2. What is the cheapest way to get rid of it ?
3. What might be the name of the upstream component that was removed ? Is this the reason for the "Whoosh" ?

Thanks!

 

[Genesis Device]

Sounds like the previous owner removed the BOV recirculation hose. Basically a common but useless mod turbo guys will do to hear the BOV vent excess boost when releasing the throttle (which I've been guilty of doing!). Sounds sort of "cool" but is of no performance benefit whatsoever. Provided the snub on the intake was properly blocked off, this won't harm anything. If you want to get rid of it, see if they kept the hose or you can make your own hose to "reconnect" the BOV to the intake...or go to a dealership and buy a new one.

 

[sharkme2]

Thanks for the info.
I don't know which one is the BOV recirculation hose, so I can't tell if it has been removed. Tried searching but didn't find anything.
Any way you can tell if it is missing on my car from the pics below ?
Also, I suspect that the Intake silencer has also been removed, what seems to be known as "intake silencer delete". Any idea where to get the stock silencer from ?

 

[sharkme2]

Turns out the air intake resonator has been removed.
It's this thing: http://www.fourgreen.com/store/scripts/prodView.asp?idproduct=5441008&cart=y

 

[sharkme2]

After replacing the air intake resonator the sound was significantly reduced. It's barely audible now.
If anyone has any tips for getting it completely inaudible, please do share.