I've started hearing this lower pitched sound coming from the engine bay. Car has an older Comptech SC, stock boost. In the video included you can hear it fairly well at the 00:12 second mark through 0:27. Then at blip of it at 00:51 and pretty clearly at 1:05-1:10. After the car has warmed up a bit the sound does not re-appear.

It may have started around the same time as it started getting cold out up here, let's say 35-40F degree mornings. When I drive later on in the day, like going out to to lunch or heading home from work... no strange sounds. My car has a block heater installed, so I used that a few days to try to help with the cold mornings and it made no difference. It didn't make this sound at all last year under the same weather conditions so I'm a bit concerned.

Any ideas on what this sound is?

[media]http://www.youtube.com/watch?v=PVoW2umsaKc&feature=youtu.be[/media]

(Link: http://www.youtube.com/watch?v=PVoW2umsaKc&feature=plcp )

Fixed Link

 

no video i have similar setup

 

Sorry, fixed link. Not sure why the embedding didn't work the first time around.

 

Kenta, try tightening the SC belt, that was causing strange sounds on my SC that would go away as the car warmed.

 

It sounds like something is rubbing possibly. I would check on this first. Make sure the After cooler, blower housing, bracket and air box are all isolated. Things do shift over time, especially the conection from the blower to ac and it could just be your blower rubbing slightly on the cross member underneath, when the car is warm and the idle goes down so does the vibration and tendency to want to rub. That is one possible thing to check. The other is I might consider removing the air box to better see what’s going on, if maybe the blower plate is loose, check all your mounting bolts, this would also let you see if the sound goes away after removing your air box becuase they can shift and rub in my experience - check the mount bolt. Also check your idle/tension pulley to make sure its tight or the bearings are not going out on it, remove if needed to check this. Check to make sure the bolt that holds on the pulley to the sc is still tight - these have been known to get loose at times if not trq properly. If you do all this and check everything, then your blower bearings may be in question. Check for any oil signs in the volute or around the outside of blower. This should keep you buisy tonight. Keep us posted on what you find.

 

that sounds almost like the heat sheild on the header or battery shield i was missing one of the bolts the other spot i would look at is the blower aftercooler interface mine was rubbing on another can you repeat the sound by holding the rpms at 1800 or wherever the high idle is when you hear the sound hope you get it figured out good luck

 

Last weekend I went to an S2000 meet and when I left the car was making the noise again. Got on the highway and it was still making the noise but then... it stopped. Didn't make the noise at all the rest of the day and I parked it. Looked at it last night to check the belt tension and the belt was just flopping around. Looked and the plastic tensioner pulley is GONE. Just bolt and I believe the center sleeve is left and small ring of plastic. So the bearing must have finally seized, fallen off, or otherwise self destructed.

Called CT Engineering today and spoke with Nate. He's shipping me out a replacement pulley and belt (belt was a little beat up too). So about $100 in parts and I will be back on the road.

 

wow i'm going to start carrying my spare pulley glad you figured it out

 

Not surprising, I’ve had this happen to me which is why I mentioned it as one of the first things to check. Sometimes things just have to fail before we can identify the problem though, at least it’s a simple and cheap fix

 

Wow! Just gone huh? Intense... Do you think the pulley could have been over-tensioned?