Turbo or Clamps

[al perna]

Hello WaGu .

The other day while climbing from Q I had a loss of Power , and Black smoke from the Exhaust. I pulled over after noticing the Pyrometer had reached 1,400 , Not Good I know .

Found a loose clamp, and all was well , or at least I thought so . When I exited the HWY , we came to a stop , upon accelerating out of the turn I heard what sounded like a SIREN !! , I let up of the fuel and it went away ? Curious as to where it came from, I looked all around but saw no rescue vehicles , nor was the ground shaking ( earth quake, Ca ) .
what I did noticed , upon every start up , when the turbo would boost , I heard the siren ?

My Question, do you think this a Turbo or Clamp Issue or ..add your thoughts ?

No white or Black Smoke
Good Boost

thank you in advance for your thoughts