i was just talking to jeff taylor he reckons the piston went from overfueling, he said the fuel gets forced past the rings by the boost pressure, and ignites around the ring lands and burns them away, sounds pretty logical tome... dont know what im going to do now, think i need to go searching for someone who knows how to tune dellrtos coz i aint driving it untuned again my pockets are getting worried after one blown engine ....