So this weekend I had a 2 hour window to work on the car (getting used to married life). I installed mulemans former O2 intake manifold with the Q45 TB.

http://www.sr20forum.com/gallery/data/500/flow.jpg
Yay!

Install was pretty easy, I want to re-route some stuff and switch to 3 inch piping for the cold side, etc. Anyway.. the car started up just fine and idles rock solid. My issue is that I hear a high pitched whine/whistle type noise and it varies by rpm. I tried checking for vacuum leaks and couldn't find any. I noticed that my boost gauge reads a tiny bit less vacuum than before. I didn't have time to pressure test, but that will be next on the agenda. I don't think it's normal, but then again I've never seen/heard an O2 stage 2 intake manifold in person. Here is a video with the sound, please don't mind me scolding my brother :D
Video (http://www.sr20forum.com/gallery/showphoto.php/photo/4640/cat/754)

i use to have the same sort of wistle on my stock motor...it drove me crazy...i changed all the gaskets...hose and everything.....but was still there.....it turns out it was the pcv valve....causing the noise...i changed it the noise went away....

with different manifolds = different air flow characteristics and sounds
could just be the sound of the manifold

when i put a kinetix plenum on my 350z it sounded like it had a S/C cause it whined alittle cause of the different design.

I heard it might have something to do with the Q45TB does anyone else have one on their O2 manifold?

it wistle 's from the q45 t/b.Before when i had a stock tb it didn't whilse.

Thanks for clearing it up!