I have an 89 si shell with a d16z6 block and head. The intake manifold and everything is off the old si. The crappy part is that it has a 4 spd dx tranny still cause i blew my si and that was all i could find. I also am still running my si distributor and a pm6 ecu that has a mugen pm7 chip. I am wondering if i run the power wire for the solenoid to my controller and then where it comes out run that to the battery with a fuse in it. When the solenoid is activated it gets battery voltage to the solenoid so i know this will work and activate the solenoid to lock the rockers and engage VTEC but will i harm anything in doing so. I know the fuel maps and everything wont be right, but would it be a power gain at all or will i break something or lose power. I will also be running a oil pressure gauge so i know when i will have enough pressure to activate it. Is anyone able to give me an answer, I would hate to do it and break something because i just put this engine in and im lovin it.

 

the vtec controller alone can be used to activate the solenoid. i am unsure of what you mean about the extra power wire....

anyway, you might lose power, hard to say w/o a graph and tune. as far as oil pressure gauges helping you know when to activate it, put it this way- if vtec is being activated by a vtec controller, it's only going to go on a the rpm you have it set at, and the oil pressure certainly should be high enough at that point! i'd not worry about that.

 

I have a really crappy vtec controller so its kinda like a toggle switch in a box that has a digital tach and i set the rpm to put power from the battery to the solenoid(therefore vtec engages), but will i break anything internally or ruin anything. It might be worse though and run really lean. Since the vtec lobes are only on the intake side on this particular motor, all it is gonna do is allow more air to be sucked in cause the valve will be open longer right? And will the spark timing be right.
I plan on setting the vtec to kick in at 4600-4800.

 

i just used an rpm activated switch(msd). its been kickin in at 4200 rpms for about 2 yrs now and nothings broke. mine is a d16a6 with a z6 head. you should be fine. i picked up about 4 tenths in an 1/8 mile.