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Mitsubishi turbos? S80

That isn't exactly right. I am a design engineer for one of the US jet engine manufactures and all of our engines, includes the ones for the F14 & F16, use "rolling element" bearings (ie ball & rollers). Rolling element bearings are used for 3 reasons, the have very low oil volume requirements (compared to sleeve bearings), they are very compact relative to sleeve bearings for the same load capacity and in emergency conditions they will operate without oil for 10-20 minutes which many times in the past has made the difference between landing and crashing. Because of the low oil flow requirements of rolling element bearings, the oil used in jet engines can very hot, roughly +300 deg F during normal operation and so synthetic is universally used to prevent coaking in the bearing sumps.

Sleeve type bearings (or so called "plain bearings" like the ones on your crankshaft) are found in large gas turbines used for electrical power generation, these engines are typicaly 100,000-400,000 HP. These bearings require large oil flow rates and because of this the oil doesn't reside in the engine long enough to get hot so they can use inexpensive mineral based oils.

The bottom line is turbocharges have evolved to the point where their bearing sumps are water cooled and the oil flow is high enough to allow reliable use of sleeve bearings with mineral based oils.






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