Engine is TM K9B, I run 22:1 which is more oil than some recommend. The ring is as old as the piston I think. If you look at the picture, part of the ring is gone, but i don’t know which went first. I haven’t changed it in 2 seasons but autocross isn’t like open track. An autocross run is about 1 minute and we get 4 runs per event. So I may put 1 hour of actual run time on a year.