Printable View
Looking over some data and curious whats causing the air load to spike on a shift? Is this normal or is it something to do with the transient fueling? Anyone seen large spikes like these before?How is average Air Mass calculated and whats desired vs average? I'm assuming it's the final airflow either blended with SD or not depending on how its setup in the tune similar to dynamic airflow on a GM vehicle?
Attachment 93720
Attachment 93721
This is normal. RPM is the denominator part of the equation that turns the MAF value into a load value. On fast shifts it can drop a couple thousand RPMs much faster than airflow drops, so you get a little load spike. Because this is a reality even for a split second, this can be the cause of detonation on shifts if the spark is aggressive and the load spikes far above the tables axis value and the ecu has no other way to reduce spark enough to control peak cylinder pressure on those few cylinder cycles to avoid it.