you usually can hear your vtec kick in if you have the windows up/down and radio off. When you get near you engage point listen for it. its real disinct. It will sound like your engine sucked in more air. Kinda hard to explain seeing how i haven't heard mine kick in, ever since i got my exhaust its louder than my system. Your vtec kicking in won't be real loud but its noticable when you listen for it.