When the fuel is injected at the end of the exhaust stroke to create a regen cycle, is the resulting EGT more or less than the 1200* we have always tried to stay under? If it is less, then why wouldn't a few runs or pulls at 1200* negate the need for a regen cycle? If it is more than 1200* then has something been done to these new engines and turbos to make them live thru sustained temps above 1200*? If so what? If not, then why couldn't the older engines be run at whatever EGT's the regen cycles create for the same length of time the regen cycles take? About how long do the regen cycles take?