90 Turbo

iTrader: (3)

Ok my miata has started making a wierd noise.

like wine/wheeew noise starts a 4psi gets louder till 6psi then soft and is gone at 8 psi to 11psi.

Is it possible I have a vacuum leak and under boast it is making this noise.
Sounds like its coming from middle-right side/pass side of dash low.

I know there is a boost sensor there for the bipes I think.

Any ideas

Thanks

Here is a vid

http://youtu.be/a7k3t3PYsLE

18psi

iTrader: (76)

you answered your own question

Doppelgänger

iTrader: (12)

Vacuum leak under boost.....hmmmm. Say that out loud very slowly...

Perhaps a boost leak under "boast"?

90 Turbo

iTrader: (3)

Your right I could have worded that better and I mispelled boost. Opps.
My main question is has this ever happened to anyone else. I have only owned factory turbo cars and the lines that are normally vac being pressure is new to me.
I looked around the vac/boast lol boost gauge and the lines seem ok. How do I chase this down I can't recreate boost with out a compressor and i worry about overpressurizing the system and messing something up?

Doppelgänger

iTrader: (12)

The first thing I'd do is go around and check all the couplers (since you've failed to mention if you have or have not done this yet). After that, check all the hoses on the intake manifold. There are so many different noises a boost leak can make, it's impossible to just say "it's xxxx". For assurance, I'd pull the inlet pipe off and check the play of the turbo shaft. When turbos die, they like to make a whine/wheeee sound as well. If you can find objects to plug up both ends of the charge piping and can pressureize them, you should have no problem running up to 20psi. If you have access to a tire pump, you can make some kind of plug and put a valve stem in it.

90 Turbo

iTrader: (3)

Well I took the hose off the boost gauge, o2 clamp and plug it still have noise.

Would the turbo only make noise at a spec psi then stop if it was going out.

90 Turbo

iTrader: (3)

I took off the intake side and there is a little play both up and down, side to side and in/out I would say less than a 1mm but if it is supposed to be solid as a rock i have an issue.

Doppelgänger

iTrader: (12)

journal bearings have some play as oil pressure "centers" the shaft and keeps everything in line. DBB turbos have very little movement. Did you chek all the other couplers?

90 Turbo

iTrader: (3)

I believe my garrett 2554 is a ball bearing turbo.
I still need to go thru them. I really need to have a friend drive so I can pin point it location a little better.
It sounds like it is coming from the passenger foot well where the ecu and 02 clamp is. thats why i thought it was a boost leak but I disconnected those lines and still made noise.

I will work on it this week.

90 Turbo

iTrader: (3)

http://youtu.be/a7k3t3PYsLE