Noise in engine at rear of turbo
 

I discovered today while listening with stethoscope that my engine noise in my 617 is loudest at the rear of my kkk turbo right where it connects to the exhaust. I never had a turbo apart but understand you have a fan blade in front to suck in air and one in rear for exhaust gas to spin turbo and boost. I have read that sometimes they carbon up so bad that they will stop. Can I just unhook my turbo and still run the engine to determine if that is what is causing my noise? The turbo spins freely by hand and does not seem to be hitting or binding . How fast does a turbo spin at idle? My noise seems to lesson at higher rpm and speed I cannot hear it at 80mph do not seem to have any power loss and no oil consumption. Noise is loudest at idle.

You are suggesting there is not a malfunction other than noise, yet you have not described the noise.

This makes it nearly impossible to diagnose.

Turbos, in general, make noise. They whistle and whine. What, specifically is your issue?