This article is still a work in progress, more measurements will be added.
There are always discussions as to whether an oil cooler is actually necessary for the BMW R18 or was just introduced to comply with emissions standards in Europe.
To do this, a driver recorded the oil temperature and engine temperature while driving at an outside temperature of 13 degrees Celsius (55 degrees Fahrenheit) via the ODB2 plug.
In the first picture you can see about 10 minutes of driving. The engine was cold when started. In the last quarter of the graphic, the engine is idling. The increase in the last quarter is the beginning of about 10 minutes of idling when stationary. When stationary, the temperature continues to rise because there is no wind.
The oil is about 10-15 degrees colder than the engine. About halfway through, the thermostat opened the oil cooler (this was verified by hand using the heat of the oil cooler).
Here you can see the peak temperature at 112 degrees oil temperature and 130 degrees engine temperature) when the R18 was stationary. We then continued driving, which was cooled again by the air. The thermostat remained open. At the 1.100 second there was a strong acceleration, which caused the temperatures to rise. Then continue your normal journey.