Peninsular Turbo whine

[Pedro]

I changed my prop (back to the “spare”)to get a few more rpm,
Speed was right where it should be 17kts at 3,000 rpm,(no excessive smoke)but I swear the turbo was whistling not whining,the pitch was higher and louder than I remember,Any thoughts?

[jleonard]

More rpm turbo spins faster sound changes.
To be expected

[Pedro]

My ears were correct,
Not a normal whine,but a corrosion crack at the turbo to exhaust housing,
I’ll Probably replace the complete turbo and elbow to be safe,