jalparacer08

Have question on a rpm activation switch to activate vtec solenoid. on a 91 civc si if i were to do a minime swap with a Z6 head could i use a RPM activation switch to activate the vtec solenoid if i were not to use a z6 computer?

Fabrik8

Yes, but you'll need to have the ECU fuel and ignition maps tuned for when VTEC engages. If you use something like a VTEC controller, you can use the VTEC controller to override and change the fuel and/or ignition tuning when VTEC engages (that's actually the most important function besides engaging VTEC). You can't do that with a simple RPM activated switch.

The VTEC ECUs use two sets of fuel and ignition maps. One set of maps is tuned for non-VTEC operation, and one set of maps is tuned for VTEC operation. If you have a non-VTEC ECU, you only have one set of maps and therefore don't have any tuning built in (while using the stock ECU maps) for VTEC operation. Engaging VTEC and having proper tuning for VTEC can be two completely separate things.