Hello Everyone!

I just joined the forum last evening, as I just become the proud new owner of an 01 996T 6-Speed. From my understanding, it's mainly stock with the exception of a FabSpeed exhaust and Agency Intake.

First and foremost, I would like to compliment this site! I have spent hours browsing the posts and am extremely impressed with the knowledge shown displayed throughout by many contributors.

Here's the issue:

During acceleration (at about 3500 RPMs) I start to hear a howling sound. The sound sort of has, for a lack of a better word (wabble) to it as well. If I let off the gas, it will go away. If I hold the gas down it will also stop at higher R's (Maybe it's not stopping, but the exhaust is drowning the sound out.)

It also seems to lose some power when that noise is present. The boost comes on strong initially, but then it feels as though the power lets up right after the initial pull.

Please ignore the boost level in the video. I did have a hose off of the N75, but that has been fixed. This was causing boost to reach 1.5 bar. Now it seems like it may be on the low side. I've seen it hit .7 bar once since I fixed it today, however, .4-.5 seems to be the more frequent number.

You can certainly hear the noise in this video. In fact, it seems a little more pronounced in the video. It starts at 3.5 seconds and you can hear it up to about 7 seconds.


Lastly, I'm not trying to dog anyone here, but I visited the Porsche dealership in my area and the head tech took a ride with me. He mentioned that he wouldn't know where to start looking and suggested that I just drive the car! He also seen the boost reach 1.5 and said that looked normal. His next statement was "It's certainly not chipped or flashed.". All that said, unfortunately, I've already lost confidence in the local dealership. After doing research, I found that 1.5 bar is NOT normal, unless modified. Does anyone know of a reputable tech in Northeast Wisconsin?

Any and all help is certainly appreciated!

Here's a couple images of the car.

 

Dang, 1.5 bar is NOT normal or safe. Glad that its reading correctly now at .7 bar.

The sound could be a rear wheel bearing.

 

Thanks for your reply! I'm thinking it's not related to a rear wheel bearing, as it only happens during certain RPM's, not certain speeds. It hardly ever happens in first gear, but has a couple times.

 

Diverter valve wooshing so they are on there way out is my suggestion.

 

Turbo surge?

 

Thanks for the suggestions guys.

Regarding the DV's: If it were the DV's, would it make the noise while on the throttle or only when letting off?

Regarding Turbo Surge: Can you please explain what this is and the types of symptoms I would experience?

Thanks again guys. Just trying to get to the bottom of this.

 

Tensioner pulley on the serentine belt is a possibility.

 

I found the issue! I noticed that a heat shield was loose. In addition, the car has an Agency air box, which was also loose and possibly vibrating against the body. I tightened both up and the sound is completely gone.

Wow am I reliefed. I thought it was going to be something major.

Thanks to all of your for your suggestions.

Landjet, the tensioner pulley is definitely squeaking a bit. I'll be changing that today.

 

Make sure you sign up for the LED taillight group buy

 

Welcome fellow Cheesehead !!

I cut my hot rod teeth drag racing on college ave many years ago.
congrats on the turbo, you will love it.

 

Nice! Sadly College Ave isn't what it once was. These poor kids today will never experience how great it truly was.

 

How do I get involved with that?

 

Not sure on the noise! Did you hear it when you test drove the car or did it just start after you bought it? Very nice BTW!

 

You bought this from Law Auto group?

 

I did. Is that bad?