The GA16DE has VTC(variable cam timing). It adjusts the intake cam timing continuously so you can't really feel it, but at 6600rpm you can feel when the VTC retards the intake cam, reducing power.
You mean for the valvetronic right? I think that is how it works.James said:it's done through their valves tho, i don't know the details but the cams are on a little ramp and i think the entire camshaft moves so the lift changes depending on where on the ramp they sit...