So I've had S2000s for a long time now and my 2002 that I picked up last year has a strange issue. When I am accelerating normally there is a slight quiet high pitch noise for a second or two. It happens in most gears, I may just not be able to hear it in first gear. It stops on its own until I shift gears and accelerate again. Nothing else seems wrong. The car drives great. I did a valve adjustment when I got it, everything was fine. I'm more curious than anything what it could be. Normal people probably wouldn't even notice it.

Any ideas?

 

Rear diff whine? Front or back of car?

 

I think I have the same, or a similar, issue. Only happens at maybe %30-%40 throttle between 3 and 4k rpm though. Very high pitched. Best heard with top down and no music or passengers talking. It only happens when accelerating. It also sounds like it's coming from the front, but I'm not sure, it's very quiet. No strange sounds from the diff when turning under load except a slight whine which I've had sense the day I got it (30k miles ago). Car runs perfect. Valve adjustment 20k miles ago, diff fluid is 30k miles old, transmission fluid was replaced 15k ago.

 

Its pretty hard to hear where its coming from, but it sounds like its more from the front of the car. Its not from the diff, I know what that sounds like unfortunately.

 

If you have an aftermarket intake or have removed the stock intake cover, it's probably intake whistle.

 

I hear this sound sometimes,sounds like a turbocharger just starting to spin up on some other cars I have owned.Only change to my car is a K&N filter.I wish it would sound like that all the time.

 

If it is a high pitched ring or whistle type sound it is totally normal. Must be a Honda thing because all of my Hondas have made the sound. I always theorized it had to do with fuel flow into the FPR or fuel rail, could be injectors as well

 

RFI possibly? Did you change spark plugs recently? Did you replace with correct resistor plugs?

 

Most likely intake noise; especially if you have a CAI or aftermarket piece, or that you have your stock intake exposed.

 

I thought I remember hearing it with the box lid on. I'll have to try that again to see if I still hear it.