there is no "kick in" it's a shift to the higher RPM cam lobes which is performed just as the two torque curves (that of the lower and higher RPM cam lobes throughout the total 0-max RPM range) cross.

in other words there is no increase in power when you get into "vtec" as you would say.

the most useful increase in power comes from the increase in useable torque across a broad rpm spectrum, resulting in a higher wheel torque when gearing is applied.

if the car can easily reach redline then there is probably no problem, when the engine seems like it doesnt even want to go above 6k, thats when you have an engagement problem. if this is the problem please reply, if not, then like i said, theres moste likely no problem.


:edit:

in laymens terms: if you can't feel a "kick" and you can still get to 8k without much of a problem your vtec system is working fine.