Originally Posted by RedlineBoyzCRX
First of all, it is all in your ECU, your TACH has nothing to do with it, you can drive the car around with no gauge cluster at all, and the car will still hit VTEC. IT gets the signal from the ECU.
That's not quite right. VTEC uses a signal from the VSS which is located in the cluster to decided whether to engage VTEC or not. But yes, it doesn't use the actual tach.
I use my OEM tach and it works fine right up to 8200.