Does someone know when does the vtec kick in on a f20b? at how much rev?

 

There isn't a 'set' rpm, the ECU considers MPH, engine temp,RPM, MAP sensor, etc. to determine when the V-tec solenoid is on or off, Its really simple to tag on a small light to the solenoid power wire and then you can see when the V-tec is on or off.