Does anyone have the specifications on the VTEC solenoid and what kind of input it expects to activate? e.g. how much current, I am assuming a 12V solenoid, but haven't checked that yet. If anyone has a circuit that's been known to work for this purpose, that would be even better. This is in relation to a H22A4 engine, but I assume the specifications are similar.

Also of interest is if anyone knows the switching circuit that the ECU uses (transistor, relay, what).

Trying to build a poor mans vafc, I have the adc, rpm sampling, dac and micro code done, looking for this last piece.

Thanks muchly.

Steve

 

ECU uses a two transistor circuits, and solenoid needs +12v for activation. Current from transistors is enough to switch solenoid.


Greg

 

Any idea how much current the ECU uses, or the transistor type? If they're using a staged configuration I'd assume that the second transistor is handling a fair bit of current.

Thanks a lot for the info.

Steve

 

I don't know the current, but you can messure the resistance of the vtec value (the spool of it) and calculate it yourself. The transisitors in the honda ecu is a japanese transistor, i think it's not a usual part.
I've build a self-made vtec controller using a TIP125 power transistor to activate the vtec valve. This transistor is common and works fine.

Doc

 

A TIP125 will work, good, I have a bunch of TIP122's lying around that should work well then. Probably overkill even. Thanks for all the help.

Steve