VTEC transition is less noticable in NSX than other Hondas.
check the FAQs
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------------------[JM] How to tell when VTEC is kicking in? Here's a nice indirect way I learned at NSXPO. Watch your oil pressure gauge as you rev up through 5800 RPM. The VTEC system consumes a significant amount of oil flow when it is activated, and you can watch your needle FALL a couple of notches as the revs climb through that point.