1SlowSi

I have a good tune on my motor, and i have got on it hard but never took it to redline. Ive put about 3k miles on it so far and its strong. Well, i wanted to test out the revlimiter so i hit it at 10psi, 9100 rpms, and yeah it worked. Well when i went to drive back in the neighborhood, i heard that WRX sound from my car. The compression dropped from 210 to 150. Smoking like a ****. It cracked the ringland. On a freakin CP piston! its sleeved if that matters. Im running hondata, and i can only guess that it was fuel cut? it ran lean as **** cause that piston lost all its carbon buildup. #2,3,4 are still good and strong. What would of caused this?