Originally Posted By: mark pruett
Originally Posted By: Miller88
- Turbos are cooled by coolant now, oil is mainly for lubrication
That's probably the most telling thing in the entire thread. If they're not oil-cooled, the stress on the oil is dramatically lessened, and I'd suspect that a coolant-cooled turbo would work even with the older generations of oils.
It's probably still a good idea to use a robust oil, and maybe even let it cool down a bit if pushed, then shut down. I know the thermal siphon helps a lot to protect the oil from coking, but turbos can glow red, and there's still energy in a spinning turbo that will go down if allowed to idle for at least a few seconds.
But yeah - back when turbos were only cooled by oil, that was a huge weakness and using a more robust oil helped a bunch.