.

[martin-av8r]

Preventing (to the degree) an oil coking is very easy: use fully synthetic oil (Mobil 1 Racing 4T). That would require the use of unleaded gas, of course. Aeroshell Plus 4 - is semi-synthetic and thus more prone to oil coking. Been there...

Also for the idle cool down time.. , some interesting info

the rotax 914 turbo is a small garrett t25 with journal bearing oil cooled

for the 915 it is interesting - rotax change from garrett to precision turbo a smaller aftermarket

company popular in drag racing , they normally dont have compressor map to see

the precision turbo for the 915 is ball bearing oil cooled only

garrett ball bearing is liquid cooled also they have a paper on why on this subject

How does water-cooling extend turbo life?​

Water Cooling For Your Turbo

Water-cooling improves mechanical durability and lengthens the turbocharger’s life. Garrett GTX and G Series ball bearing turbos are designed to be cooled

www.garrettmotion.com

Robert Young is the engineer owner and founder of Forced Performance

he work on turbo for many year , he create is own high quality brand Xonarotor turbocharger

and create is dual seal and billet wheel before the OEM

Variable-Preload Ball Bearing Cartridge - Xona Rotor

Engineered for Life Xona Rotor’s ball bearing system is unique. We spared no expense in its specification, starting with a high-precision ABEC 7 angular contact dual-row ball bearing cartridge. Its M62 tool steel races and silicon nitride ceramic balls deliver the highest possible load capacity...

xonarotor.com

he explain in this video the difference in cooling needed with journal bearing high flow oil cooled only

vs ball bearing with no water cool with there restricted inlet low oil flow to the centersection ball bearing cartrige , hydro damping cartrige and oil cooked , hydroplaning ball with to much oil flow and rpm effect

 

[Burrengyro]

Products of gasoline combustion are mostly water vapor and CO2. Some of it goes to crankcase, and condense on oil if oil temperature is below water boiling temperature at the flight altitude.
If temp of the oil were over 100C - water vapors would not condense on the oil and would not become a part of lubrication stream. That is my opinion and I don't insist it is correct, but as I said, it is easy for me to replace the thermostat and forget about that problem, be it real or imaginary.

Hi Inquiring Mind,
How is the Improved Racing oil thermostat system working out for you on your Magni?
I have no thermostat valve on my 914 ELA072. Partially covering the oil rad to get 95 degrees C is a pit of a pain.
Many thanks, John H