macster,

Great answer and thanks. I tend to think that people change their oils more frequently than necessary. It is not 1966 anymore and oils and engines are just a lot better than they were when 3,000 miles was the standard.

 

Oil temperature runs hotter with high RPM - for example - at the track. Heat will accelerate the breakdown of the bonds between the hydrocarbon chains in the oil & breakdown/boil off the additives - and eventually reduce viscosity and shear strength. OEMs do accelerated life tests by running the engine at high RPM for a continued period of time. A few 20 min track sessions will probably not make that much difference - but as Macster says - oil change is cheap insurance - my point was that for normal users M1 is just fine - but I also acknowledge the point that extreme users - might prefer oil with higher HTHS, VI, FP, ZDDP etc.

http://www.bobistheoilguy.com/oilshear.htm