M1 0/40 is really a heavy 30. I could absolutely see a tuned LS motor beating the tar out of that oil on a track day.
M1 15/50 under-performing is no big shock. That oil is a total knockdown. Just this past week we dealt with a boat that had 9 psi hot oil pressure on M1 15/50. Changed the oil to GTX 20/50 just to see what would happen, and hot oil pressure jumped up to 40 psi.
My favorite engines to test heat shearing on are Volvo Penta small block engines. No oil cooler at all. Dump the throttle, and the remote oil filter mounts get hot enough to burn bare skin. Nearly hot enough to do it through gloves.
M1 15/50 under-performing is no big shock. That oil is a total knockdown. Just this past week we dealt with a boat that had 9 psi hot oil pressure on M1 15/50. Changed the oil to GTX 20/50 just to see what would happen, and hot oil pressure jumped up to 40 psi.
My favorite engines to test heat shearing on are Volvo Penta small block engines. No oil cooler at all. Dump the throttle, and the remote oil filter mounts get hot enough to burn bare skin. Nearly hot enough to do it through gloves.