>You might want to look at the oil drains on any Lycoming engine, they
are
Aluminum AN  fittings.<

   Rick about the al fittings in the engine compartment. As an Former
Engineering Test Pilot for a Major GA manufacturer I can safely say that
there is difference in the environment for the oil drain vs the turbo.
The turbo in operation runs very red hot in operation.  But the oil pan
rarely runs that hot except in a fire.

Jack Webb
L 360, LIV
ATP, BsAE