I'm pretty new to this engine, but the dyno plots that I've seen for both stock and modified cars tend to show almost a straight line for horsepower all the way to redline or close to it. On your plots, HP seems to plateau around 7000 rpm and torque drops significantly from that point to redline (which makes sense due to the relationship of HP and TQ). I would think if the car were pulling timing or it were a fueling or ignition issue, that you'd see more of a dip or spike, rather than just a leveling off... but that's sort of just speculation on my part.
I know that's not really a solution for you, just an observation.
Well I went back and saw that other M3s on the same dyno exhibit the same behavior, so maybe it's due to the elevation or possibly not having enough airflow in the dyno room. Your AFRs look kind of weird in some of those pulls too. They don't dip as rich compared to the other cars on the same dyno.
Last edited by wheatpaste; 12-07-2012 at 05:35 PM.