JMChristopher

Ok, so I took my stock 07 to get a new stereo put in and also got some dynamat put on the doors. I got it back last week and now I notice a higher pitched whistling noise very reminiscent of boosted motors (not as loud of course). It only does this in the upper rev range above 4k or so and it increases in intensity the higher I rev. This does seem to go away after a couple blasts to redline. It doesn't appear that I have any loose hoses. The airfilter is in place and the airbox is closed. The intake at the throttle is also secure.

I have entertained the thought that because of the dynamat on the doors I can now just hear the induction noise better, but that seems like a stretch. The car is running fine otherwise.

Does any one have any ideas?

Grillo

you have a hidden supercharger ! (JK) no clue

zeroptzero

Whistling noises are consistent with the intake system.

It might be a similar effect as adding a hardtop, once you add a hardtop to the car you will notice quite a bit more mechanical noise from the powertrain.

If the shop didn't touch anything mechanical on the car you should be safe.

darcyw

...or your getting the high pitched wine from the stereo feedback into the speakers.

darcy

JMChristopher

Thanks, they didn't (They shouldn't have) touched anything in the engine bay. I guess it is a bonus, it does sound quite nice.

Another anecdote here: I have a Honda Prelude that I took to a jiffy lube (for the last time) for an oil change and they of course checked over everything looking for ways to extort more money from me. They checked the throttle body for what ever reason by taking the plastic intake tube off and couldn't be bothered to put it back one. I was driving home and gave it the beans when I was pulling out into traffic and as I rev up I hear this whistling noise. I drive the next couple miles to my apartment and then open the hood to see what the deal was. It was the intake hanging off the throttle leaving a nice wide gap for debris to get sucked in.

This sound on my S made me think of this incident and despite there being no signs of tampering or loose connections in the engine bay, I have to wonder.

Thanks again.

JMChristopher

I think I have ruled that out too. It happens even when I turn the volume all the way down.

SgtDuracell

post a vid.

JMChristopher

I will see if I can do that.

wsteun

Alternator whine maybe? I've heard high pitched whining come through speakers before as the car increased in RPM's.

JMChristopher

A wine over the speakers seems likely, I will make sure it isn't that next time i drive it.