The turbo is cold, and there is grease in the center section. As the water/coolant temperature goes up and through the center section, the grease liquifies and everything spins really easy.
This is why you see the turbos on YouTube spin for a long time after shutdown. The grease is designed to work at the same temperature as engine coolant.
Last edited by Boosted Performance; 03-02-2018 at 12:19 AM.
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