Whine from 2750-2950 RPM?

[Jonny042]

Hello all, went on a short highway trip yesterday and cruised at 61-63 mph in a heavily patrolled 55 zone for an hour or so.

Normally I drive a little faster, up in Canada we are given a little more leeway....

My question is, I realized my car makes a whining noise from 2750 rpm to near 3000 rpm. It is quite load to the point of being unbearable and I kept finding myself slowing down to a lower rpm to make it stop.

It's a resonant sounding noise, quite high pitched, and sounds basically like gear whine. It is definitely engine RPM related and I can hear it separately from the final drive whine (which is much quieter).

Then when driving home through town I realized my car spends a lot of time in this rpm range and this noise is greatly contributing to the interior sound level.

The only thing I can think of is the intermediate shaft?? Yikes.

[Flieger]

The only thing other than the gears I could think of is fan noise, but my car spends little time at those low revs.

[Jonny042]

Well, I just took the fan belt off and ran the car for a sec.

90% of the noise I THOUGHT was fan, is still there!!!

I am going to have to get to a PCA gathering (means a few hours drive) listen to some other 911's.

Or rebuild everything this winter....

[agfours]

Interested in what you find - I've noticed a little bit of a metallic ringing sound at that RPM range as well, and mine also seems to be coupled with a little bit of a sag in power delivery as well (however, based on your characterization of the sound, I'm not sure mine is as pronounced - I'd give it a 3 or a 4 out of 10 as a contributing factor to the overall engine noise - note that's with top down).

[GothingNC]

What kind of exhaust set up do you have?

I have SSI's with the Dansk sport and it has a slight whine from 2800 to 3000 RPM.

Had a few folks check it out and said it was normal since the noise eminates from the muffler.

[Hodgey]

Johnny,
Does it do it when you're static and out of gear?

[tobluforu]

Muffler bearings.

[GothingNC]

Originally Posted by Hodgey

Johnny,
Does it do it when you're static and out of gear?

Yes.

Clutch in or out and nuetral/in gear the sound is the same.
Just the nature of the beast

[Jonny042]

Mine does it when static, trans in or out of gear, and clutch engaged or disengaged.

I should clarify (and now know for sure) that the "whine" is there at all times and at all rpms, it is simply more pronounced at certain rpms.

Having eliminated the fan and or alternator as a possible source of the whine, my only remaining options to check without an engine out teardown are the distributor, and the muffler bearings

[GothingNC]

Can you post a sound clip?

[Porsche Head]

Gear whine from the diff, if you let off does it go away or change. Did you install a new shifter or is the shifter binding holding the shift against the gear? Try taking the load off the shifter as you are driving to see if changes. Sounds like it is in 5th only so related to gear.

[Jonny042]

FINALLY (this thread is a year old LOL) got around to uploading a video of the car from the inside, recorded on a gopro.

Even when watching this on my computer the resonance of the noise just drills into my head!

Any ideas are appreciated.

Video link: Porsche 911 Engine Whine - YouTube

[mnez]

Can't really hear it very well. An intake noise? Mine whisles like it has a small turbo attached, goes away when throttle is closed.

[kodioneill]

What year is the vehicle.

[Porsche Head]

It is hard to hear, the fan whine and other noises (typical Prosche sounds) mask what we should be listening to.

Cliff

[Jonny042]

Originally Posted by kodioneill

What year is the vehicle.

1987 3.2 basically stock.

[Jonny042]

Originally Posted by Porsche Head

It is hard to hear, the fan whine and other noises (typical Prosche sounds) mask what we should be listening to.

Cliff

Right around the 32-33 sec mark of the video, the resonant whine can be heard over all the other (more pleasant) noises.

To summarize the rest of the thread, I have eliminated the fan and alternator as a possible source of the noise.

Thanks!!!

[kodioneill]

I can hear it for sure. I'm thinking it may be air induction in either the idle control or the evap system. Try blocking off some hoses with a clamp to see if you can change or eliminate it.

[Jonny042]

I did not think of that - although it does it regardless of throttle position, and hence, manifold vacuum.... but it's worth a try!!

[Locker537]

I'm curious - did you ever figure the sound out?