small hole in stock R33 bov

[Sime]

Mine seems to make a soft whistling noise under very low throttle and makes a soft peeoow noise when I release the throttle. It can get quite annoying as it will just keep whistling and peeoowing while I adjust the throttle to maintain a constant speed. I've heard of people blocking it off but I'm not sure why or whether it will effect the performance of the bov. Should I do this and if so, what do people use to block it off?

Thanks

[R33vit]

I use masking tape to block it, but only when Im going to the drags. For circuit I leave it unblocked.

The car feels like it surges on fine throttle responce when its blocked.