Weird Noise while in vacuum

**csre9** · 12-11-2008 08:22 AM

So\

**SpoolPastYou** · 12-11-2008 08:30 AM

Originally Posted by csre9

So Im cruising on the highway yesturday about 75mph last night and hear a slight buzzing noise/ drill from the passenger side. I was about 12in in vacuum and when I would make boost the noise went away...
There is no noise at idle only when driving in vacuum.
If it were my passenger side turbo wouldnt it make noise under boost as well?

Any input would be appreciated, thanks.

Also, radio and air system were off as well, so that knocks out any ideas of the noise coming from either of those.

yup same thing happened to me and freaked me out...friend said it was just the weather change..when i was in vacuum it sounded like a wierd boost noise but wen i was in boost no noise wat so ever.

**CONTROL ONE** · 12-11-2008 08:33 AM

Does temperature effect the sound you hear?

**tike0rz** · 12-11-2008 08:44 AM

Check if its coming from your boost gauge...mine used to make a sound in vacuum until I traced it back to a loose hose.

**AudiSportB5S4** · 12-11-2008 09:14 AM

do you have upgraded diverter valves? My hyperboost valves make a woooooo sound in vacuum. Never in boost, but in vacuum only. I called Stratmosphere, they said it is completely normal and also is dependent upon your intake setup. I have a RS4 airbox with most of the bottom cut out so I have lots of airflow.

**Allaidback** · 12-11-2008 11:19 AM

I was about to post the same question a while back. I didn't start hearing it till the cold weather, but sounds like its coming from under the car. only at 12-10hgs...probably from the hole in my airbox?

**sCeRaXn** · 12-11-2008 11:43 AM

My car does it too. Temperature cant be to blame because it started in the summer when it was hot a hell, and it still does it now on 30deg mornings. It doesnt do it all the time...only when ive been driving for atleast 10-15min and when the car is completely warm(oil and coolant). Its definitely not the dentist drill noise...its more of a weird tone like the one you used to hear when a tv station went off air. Im also positive that its coming from the passengers side turbo because it got ALOT louder when i did the piggies. I could barely hear it even with the radio off...now i have to turn the radio up because it gets so annoying. Its not really loud, but the constant tone gets to be like nails on a chalkboard.

The only thing that seems constant is that its much more noticeable when its really humid. Like i said, temp doesnt have much of an effect but the humidity definitely does. So ive come to the conclusion that my turbos are arthritic lol

I dont think its anything to be too concerned about. When i was putting in a new clutch and doing the piggies i checked out both turbos and they were in really good condition. I couldnt see the compressor wheel, but i didnt feel any dented or chipped blades...and there was little to no shaft play. The exhaust wheel was in perfect shape. I was actually really surprised at how good of a condition they were in. The turbos are one of the few things thats never been replaced on this car...and with 157k miles on the clock i was expecting it to look like a grenade went off in the turbo. I guess i was lucky and got one of the few sets of good k03's from BW. The fact that its never seen anything above 10psi helps too lol

**csre9** · 12-11-2008 12:04 PM

Originally Posted by tike0rz

Check if its coming from your boost gauge...mine used to make a sound in vacuum until I traced it back to a loose hose.

This might be it.
The day I hooked by boost guage up in the left center vent I didnt zip tie the vacuum line to it so after a few hours of driving I got into it with the music up and only saw 13lbs. I was so upset but later on with no music had to merge onto an interstate with no merge lane and I heard the rush of air coming from the boost guage and it was loose.
Lately my GIAC has been acting up and ive been thinking its been my n75 but this may be it.
Maybe a vacuum line from the boost guage is loose. Ill check it out today.
Also, I have a pretty large custom intake so that may be it.

**csre9** · 12-11-2008 12:13 PM

Originally Posted by AudiSportB5S4

do you have upgraded diverter valves? My hyperboost valves make a woooooo sound in vacuum. Never in boost, but in vacuum only. I called Stratmosphere, they said it is completely normal and also is dependent upon your intake setup. I have a RS4 airbox with most of the bottom cut out so I have lots of airflow.

I have 710N dv's and a custom intake.

But I do know what your saying about the dv making noise.
I have a Forge DV and ecs tuning intake and turbo inlet pipe on my GTI and in vacuum there is a woo sound.

Thanks for the input

**csre9** · 12-11-2008 12:13 PM

Originally Posted by sCeRaXn

My car does it too. Temperature cant be to blame because it started in the summer when it was hot a hell, and it still does it now on 30deg mornings. It doesnt do it all the time...only when ive been driving for atleast 10-15min and when the car is completely warm(oil and coolant). Its definitely not the dentist drill noise...its more of a weird tone like the one you used to hear when a tv station went off air. Im also positive that its coming from the passengers side turbo because it got ALOT louder when i did the piggies. I could barely hear it even with the radio off...now i have to turn the radio up because it gets so annoying. Its not really loud, but the constant tone gets to be like nails on a chalkboard.

The only thing that seems constant is that its much more noticeable when its really humid. Like i said, temp doesnt have much of an effect but the humidity definitely does. So ive come to the conclusion that my turbos are arthritic lol

I dont think its anything to be too concerned about. When i was putting in a new clutch and doing the piggies i checked out both turbos and they were in really good condition. I couldnt see the compressor wheel, but i didnt feel any dented or chipped blades...and there was little to no shaft play. The exhaust wheel was in perfect shape. I was actually really surprised at how good of a condition they were in. The turbos are one of the few things thats never been replaced on this car...and with 157k miles on the clock i was expecting it to look like a grenade went off in the turbo. I guess i was lucky and got one of the few sets of good k03's from BW. The fact that its never seen anything above 10psi helps too lol

Thanks for the input bro.