Turbo charger sounds like a supercharger...
 

So I'm driving along one day and decide to floor it. In 4th, I hit boost cut, which is normal for me now. I noticed a puff of smoke (I assume from the boost cut). So the next time I get towards boost it starts wailing like a police siren. It's ridiculously loud. I have read many threads on other forums about this and I'm running out of things to check.

What do you recommend I check? What I've looked at so far is below.

Things checked:
Intercooler pipes visually and pressure, no leaks
Compressor and housing looks good, no damage obvious. I did not pressure test the compressor housing.
EGR block off plate, was tight

I still have all my fluids and it sounds fine out of boost. But as soon as I get close to and in boost it wails. It does still make boost though.

I guess I'll go pressure test the compressor housing and see what that shows.

Boost cut is normal?

Hell man, it's like hitting a damn brick wall. If i were to guess, i'd assume that was the source of your problem.

Maybe wastegate flapper. Not sealing properly, or doing something funny.

Lol yeah it is. It's annoying too. I had a mbc, found out that did nothing cranked the wastegate up. Barely hit 15psi and I was tapering to 10 by redline (no vvt control). I assumed because of the cold I was getting boost spikes. But if I keep my foot in it (I've done this like twice) as soon as I get past like 4.5k rpm and boost starts to drop I'm fine. sometimes its so short its almost like it's hiccuping.

Anyway pressure tested the housing got blasted in the face by air. The dumb barb that goes to the waste gate, when the turbo is new, was leaking (I had previously blocked this. I'll get a cap and see if that fixes the issue.

compressor wheel is hitting the housing. surprised it will even make boost.

It is 100% not hitting the housing I took it off and checked to be extra positive. That was the death of my last turbo. Pretty sure it was just a boost leak put of my compressor. I just capped it and am about to test it.

and it sounds like this:



??

It's not nearly as bad as that. I'm trying to upload pics but my phone is being gay and won't sync. It sounds more like this .
Or like a police siren. With the compressor barb capped it was mildly better. I soaked everything in throttle body cleaner and didn't notice any changes. It is doing this weird idle at 1900rpm for like 60 seconds then dip then high then dip. But I think that's more because of my MS2.

https://www.miataturbo.net/attachmen...ine=1358715496
IMAG0081 by Gorillazfan, on Flickr
https://www.miataturbo.net/attachmen...ine=1358715496
IMAG0080 by Gorillazfan, on Flickr

does it not look like impact marks on the 9 clock spot in that pic? more or less what my turbo housing looked like from the video i posted.

That's a casting imperfection and has been there since I bought the turbo. Also the compressor housing is completely smooth, no gouges.

Could it A) Be insufficient oil? I have a restrictor in. I've run it this way for almost a year. Though I am over due for an oil change.
B) A dying fuel pump?

Wastegate flapper.

Could you elaborate? Is it not opening fully? I also lessened the tension in the wastegate last night.

Not sure how relevant this is but I had an exhaust leak pre turbo in my WRX that sounded identical. In or near boost it sounded like a dying turbo.

Is there any shaft play at all?

Minimal. Feels like its within tolerances of a new turbo. No pre turbo leak. Ive had one before, then I never built boost really and it was ungodly loud.

Ok so we pulled the oil restrictor. It didn't do anything. I pulled the mbc. It didn't do anything. I routed the wastegate signal from the compressor port to the wastegate and it didn't do anything. Could I have torn the diaphragm? We put pressure through the wastegate signal line and it did open. Idk it rattles now too.

your TURBINE housing is bouncing like what brain was telling you, except exhaust side... now its chewing up your bearings. That and/or your wastegate flap is disintegrating.

That's kinda what I was thinking I was just trying to avoid pulling that side. Not that it's difficult, it's just cold out.

I'll do that tomorrow. I guess I'll either replace the turbo with another 100 ebay or actually buy a grown up turbo...I could also throw my holset on...Looks like I got motivation to finally finish my new manifold and 3" exhaust...

if its not too chewed up, a rebuild kit and some careful alignment pre-disassembly could save that turbo and you 80 bucks.

I'll check it out. I do have a rebuild kit for my first turbo (t25) I wonder if any of the parts would interchange...