Another '05 LGT "strange noise" thread

'05 LGT
5/mt
Stage II 91 oct
AVO TMIC
Cobb catted dp
Grimmspeed catless up
Magnaflow rear cans
Stock BPV
VF40
93k

Symptoms:
Whistling noise while boosting from 1psi through 17psi, consistent (i.e. doesn't get louder w/more boost), not present on decel, at idle, or when driving off-boost.

The whistling is not a screeching sound. It does have a bit of a "flutter" to it.

Hard to describe, but the closest I can come is if any of you have ever run a catless turbo-back of any decent diameter w/no resonators or mufflers, you know how you can hear the exhaust turbine noise in the exhaust note? Sounds exactly like that except that its not coming from the exhaust.

The motor was just (about 100 miles ago) put back together and back in. The car was purchased as a non-runner so I have no baseline to go off of except that my bone stock '05 5eat car doesn't make this sound.

Every gasket and o-ring in and on the engine was replaced while it was out, including the ones pertinent to this issue:
Compressor outlet to TMIC inlet (Mr Gasket 738g)
BPV (stock) to TMIC gasket
OEM-but-new TB hose
TB gasket
Intake Manifold to TGV to head o-rings&gaskets

It idles tabletop smooth, pulls strong and steady vac, runs a tick rich @ WOT under load but it holds steady boost. No black smoke out of the exhaust. No random oil spray detectable in the engine bay.

No intake related codes, but it did throw a P0011 on the first WOT pull in 3rd to redline which I cleared and hasn't come back (yet?).

I thought it was the stock IC leaking, so I replaced it with an AVO TMIC and the noise is still present.

I'm pretty confident its in the intake system "somewhere" between the airbox and the intake ports and I've been focusing post-turbo but could be wrong?

I won't have access to a compressed air source or smoke machine until mid-next month and I don't want to wait that long. Any insight would be appreciated.

Thanks

Ryan

Pull the down pipe and check for shaft play on the turbo.

Mine whined for about a month in boost before it began to whistle one morning. I stopped driving it with in a 1/2 mile. I replaced the turbo before it blew and took out the short block.

Lucky, I was that close to home.

Thanks for the response, I had the entire motor out of the car and when it was, I went over the turbo. Zero side to side, up down, in or out and it spun freely. Compressor blades are not making contact with its housing, nor is the exhaust turbine making contact with its housing.

I agree it is time for a new turbo, and there's a brand spankin' reman'd BNR sitting in my garage awaiting the next payday for the mandatory Infamous filtered oil line kit and a free hour or 2 next weekend.

I'm not ruling out the turbo and I appreciate your insight, but excluding that, is there anything else you can think of?

Thanks!

I found a youtube video that describes this as "normal".

Stage 2 Whine And Hiss 05 LEgacy GT - YouTube

Stage 2 Whine And Hiss 05 LEgacy GT - YouTube

Listen with the speakers up to the first few seconds of the video. It's over at 4 seconds. There's a bit of a hiss then the sound I'm used to of a BPV doing its thing. I'm hearing this hiss but louder and not with the windows up (only down).

If I knew anyone that could either A. operate a camera without hurting themselves or B. drive a stick without, well, hurting themselves, I'd make a video of my own. But this is Arkansas. I saw a rotary phone still in use the other day. True story.

Update: I was barking up the wrong tree looking at the intake side.

I just installed the BNR and replaced all of the exhaust side gaskets on the passenger side (due to my dropping something into the UP that ended up bouncing its way into the crossover).

Anyways, the whistling is gone.

The cause? Manifold to UP gasket.

Searching after the fact for "whistling" noise turns up about 20 threads, all of which point to that very gasket.

HELLO . My 2005 legacy gt makes a similar noise , Mine however has a sputtering -fluttering sound that doesnt effect power. It happens at at acceleration mid range rpms, just prior to shifting. In case i dont get on the forum for a week or so if someone wants to shoot me a direct email telling me what they think the sputter/flutter sound is caused by ? Please do. Im Thanking You

WOOPS forgot to include the email address. generaljoe67@verizon.net