Cam Timing adjustments.Intake side
Advancing timing - turning the pulley counter clockwise - you gain power at low RPM.
Retarding timing - turning the pulley clockwise - you gain power at high RPM
Most adjustable cam gears can be moved +/- 10 degrees which is 20 degrees of cam timing on most aftermarket cam gears.
Variable valve timing on the intake cam. 3 different setups. Seems to be popular on GT-R's in Japan now.