Originally Posted by dan l

The decay is part of the short term knock protection. I do not suggest messing with this routine, it is a great tool to protect a street car. Instead I've had great sucess trying to tune out this knock. Another option (if your into changing routines) is making the ignition timing go to 10 or 0 when the clutch is in. This provides more boost potential and in my first gen dsm, has eliminated shift knock during flat shifts.