It's hard to tell as the gauge is hard to read when the car is pulling like a train. Had a friend in the car watch the ultragauge. It showed 18.5 at 5k before the car cut off. Before the gauge, I measured the supercharger pulley just to make sure I wasn't accidently running stacked from the prior owner. I would think belt slip would be gradual rather that the car losing everything. I wonder if the supercharger clutch is letting go. I guess I could check clearances and then maybe straight wire power to it.