It's only after about 15 months of ownership that I began hearing a slight "pfwrieee" whistle sound coming from under the car when accelerating gently in 2nd. Sometimes I can hear it, sometimes it's not there. But by now, that little 'turbo' sound, hardly noticeable but it's there in 2nd, 3rd and 4th. When accelerating very gently it's not there, pushing the accelerator 1mm further down, it's there, pushing the pedal 1mm further it's gone again. When lifting the gas that same 1mm, it's there again! Can it be a problem with the exhaust? Something else? It's hard to say if the sound is coming from the engine compartment or rather from the back. Thx for any info. I will go to the dealer with it, but you'll see the car will not have the problem that time, like when going to the dentist

 

i here it on mine too.......a faint whistle that sounds when accelerating...but not if a let go of the gas...

 

You don't have gears, do you?
In those 15 months did you change diff / trans oil?
If yes with what?

Check the airbox, see if it is sealed all around.
Check for air leaks in general.
Can you reproduce the sound with the hood open and "throttle-ing" by hand?

Thats all I can think of right now.
Let us know what you find

Or it could be the expanding air around your Berlina BLACK exteriour with those high European temps lately

 

It's normal. Not all S2000s do it... just some, like the ITRs and Sis. Its the throttle thats doing it (caused by the rapid movement of air). If you put on CAI... expect it to be amplified 10 fold.

 

This will also happens if you have an aftermarket sound system that was not installed correctly. If the system is not grounded properly, you'll get alternator whines, from noise.

 

Not sure if it's the same whistle sound but I hear whistle type noises from the air pump located under the drivers side headlight under slight acceleration. My car has always made this noise and I've had no issues with it at all.

 

could be the tranny. impossible to diagnose without at least knowing where its coming from since practically every part of the S can whistle

 

My car made a whistling noise since the day I bought it. To me it sounds kind of like a wrc car (transmission), just not nearly as loud. It does it in all gears if you listen closely, for some reason 2nd gear is more pronounced.

 

Two different types of noises. I actually like the whistle sound.

 

Open your hood, engine running, and pull on the throttle a couple of times... if you hear it.. its not the tranny.