vtec controller - aka VAFC for instance. You're miles off with VTEC. VTEC is controlled by the ECU (computer) in the car and a few parts on the engine that are the VTEC (switch, sensor, cams, rockers...). You don't 'activate' it using some part, it's in the computer you need to get to make the engine run properly - a P28.

 

oh yeah. my ecu is p08 which is a dl5b vtec ecu , but its AT!! somehow they say it work, but the engine light would come on.

 

The P08 will work, but you need to wire it correctly. I don't know a great deal about the P08 other than it uses a 1-wire O2. You should try to find a pinout for the ECU and then make sure the wires are run correctly.

 

Can't you also use a P28 ecu?

 

Trying to run ur Vtec consantly is a very bad idea...the car comes from the factory with the perfect RPM setting for VTEC to activate...it a complicated thing that has to do with air fuel ratios...if you lower your VTEC activation point without altering your Air Fuel ratios you are going to seriously mess up your car...try chipping your ECU with a JUN racing or SPOON ecu chip...some will lower your VTEC activation point and also alter everything that comes attached to lowering your VTEC point

 

VTEC engages in the high power band.. i was told lowering it would mess up the mid range band..