What oil temps would require a more viscous grade?

[jqgz]

Say for a car that will be used on a hot track. What oil temps would be high enough that you would need to step up a grade? Or is it more oil pressure related?

 

[Graham Piccinini]

I'd say both. Above 230F degrees I'd just go with M1 15w50.

 

[ZedzAmg]

Depends if the car is specced for a 30 or 40 wt, is it modified, boosted etc. I know my amg gets 40 wt from the dealer and temps will hit 250f. I'm ok with that if mercedes is. I run 10w30 in my twin turbo 6cyl if I'll be running it hard

 

[dubber09]

Also, thicker oil may cause oil temps to go even higher.

 

[NoGoal]

My Audi occassionally hits 275 F on hot track days. I just stay with the 5W-40 that has VW 502 approval. No issues, but I do change it at 3500 miles or 6 track days.