I have a GT30R and when i turn my car off i can hear the turbo spin for at least 30-45 seconds. Does this sound normal? Im asking because this is my second try with this turbo...First one had to be rebuilt by precision only a few days after our dyno session (They say it was due to a "foreign object"...but it always had a K&N on it) and it also sounded like this too. There isnt anyone around here with a ball bearing turbo, so i just cant go out and listen to theirs. I was running a 3an line on the first one, now im running a 4an and restrictor on this one too.

 

How's the oil return setup? I'm using the same turbo, I can't hear it unless I give it enough throttle to start building boost, also with a K&N.

 

10an return...looks fine. Can you not hear it when you shut your car down? I can hear mine spin down for quite some time

 

ball bearing turbos will spend for a bit after the car is off