I know what you are all thinking, but trust me, this is not that thread.

About three weeks ago I started hearing a whistle/suction noise from under the hood while driving over 4k RPM, especially under acceleration. Now I do NOT have an Intake -- the only thing I have in that area would be a K&N drop-in. However when I installed it, this noise was non-existant -- this came later.

I got a spacer put in two weeks ago, but this noise was evident before the spacer. A G35C racing next to me @ Englishtown heard it as well (while in his car, full throttle, windows shut). When the spacer was installed I requested that they check all hoses -- no cracks or lose fittings he said.

So, what else could it be?

 

just say its a turbo :P

nah seriously i dunno
its obviously around the intake or otherwise it would whistle all the time
look around the tube or re seat the filter an give it a go

 

lol unknown supercharger

 

Lol I wish I had an unknow supercharger. But then I would hope I run better than I did, and put down more than ~ 250whp .

By all the time do you mean throughout the powerband? If so, that makes sense to me. However, I wouldn't think a drop-in would have much of an effect on sound. That could be it, but I think I would have noticed it prior to a few weeks ago -- I have had the drop-in for sometime now.

 

Rev it up from a stop and see if it's still making the sound. If it doesn't make the sound or if the sound is a lot quieter it's probably just your intake

 

does this noise occur when you rev the engine at a complete stop? or only when moving?

 

check for a possible vacuum leak

 

I did that today at work on my break. I revved it up slowly and then quickly while leaning as forward as I could. Could not hear a thing resembling what it sounds like under load.

It could be the intake, but a drop-in making a noticeable noise? Didn't think that would be the case.

When the spacer was installed I requested that they check all hoses -- no cracks or lose fittings he said.

 

yea i would put my money on the intake
just make sure everythings tight

my injen intake whistles under load thru the entire power band
but you cant hear it sitting still
and when going up a hill from 0-60 it gets quiet loud, ied had people turn to look at my car because of it in town

 

intake

 

Something under the hood is whistling on my z too.. I don't think it's the intake as the noise comes on even when the car is stopped. It is probably a vac leak though I can't seem to locate it. I was thinking about changing to nizmo hoses anyway, though I am not sure what this will really do for performance.