Chirping Noise
 

On a seemingly random, but not infrequent basis, my S4 will produce an intermittent chirping noise during acceleration. The sound is distinguishable from the standard turbo spooling. The noise can potentially be heard at any point starting from around 3500rpm, and drops out again around 4000-5000rpm. I haven't been pushing the car too hard (yet - 1400mi), but I notice this currently in second and third gear. The car has a manual transmission, and is stock.

The noise isn't very loud, and doesn't come with any really noticeable drop in power. I haven't decided yet whether there is a slight power drop, so you can see the subtlety here.

Any thought on what this is, and if I should have it looked at now? I'm tempted to wait a while and see what happens, but I don't want to risk any serious damage to the car.

Me too...
 

Now that I've got a quiet exhaust, I've noticed this in my Tip. It almost sounds like the tires breaking loose, but it occurs under moderately heavy throttle which could not break them loose. I'm very puzzeled cuz I can't really locate the source, whether it's under the car or in the engine compartment.

Let's track this one!!!

Yes! Same here on my stock '01. No loss of power. Just a funny sound sometimes.

Mine chirps from engine compartment sometimes...
 

Took me a while to realize it was my car, and not some truck or car I would be behind, etc. :)

I thought it was random at first, but then I realized I don't seem to notice it as much under hard acceleration as I do when I am just cruising (but it may just be that I can hear it better then). During my commute to work, the chirping seems to occur only after I have been driving hard over the winding back roads that make up the first 20 miles (including several stop signs), and then (due to traffic) usually have to ease up and cruise at ~60MPH (roughly 25MPH less than my normal top speed on the back roads) for the last 5 miles, which is all 2-lane highway. Seems like the transition from fast-stop-fast-stop-repeat to steady speed cruising sometimes induces the noise. However, it doesn't seem to start until I have been cruising steadily for 2 or 3 miles (again, I may just not notice it for a while).

Every now and then I'll get a chance to pass on those last few miles of 2-lane, after the noise has started, and I don't notice any loss of power at all. I do notice the noise again after passing and resuming cruising speed, and it generally continues until I reach work.

Now that I think of it, I don't think I have ever noticed it on the way home. Hmmm. I'll pay closer attention to it and try to further narrow down exactly when it happens. I'm really not too worried about it, but it is a bit annoying. I love the normal turbo whine, but this is completely different, and is a distinct chirping.

Hopefully we can determine what it is, and find a fix. Darn, I could have called Car Talk (radio show on NPR, for those who don't know) about it this morning! ;)