how to : Vtec engagement from Shift LIGHT?
 

In my continuation to "dominate" a buddy's SI im in the search of information of vtec engagement via tach shift light....
I know I need to convert the signal to a negative pulse, but by using the tach it will be completely adjustable....

SOHC VTEC ZC........coming to a neighbourhood near you soon.....
:working: slapin' dat ass

HHHmmmmm
 

You could use a plain jane bosche relay. I'm not sure what the pin out is, but connect the vtec solenoid and a ground signal through the switched pins on the relay. Then connect the positive shift light signal to the relay so that whenever the shift light comes on, it will trigger the relay to connect the vtec solenoid and ground wire together.

I'm sure this won't make too much sense. I'll try and find a wiring diagram or something for you.

I remeber seeing it on a web page long long long ago. I'm using a Fields SFC controller to activate my vtec (and adjust fuel settings) on my non-vtec equiped ECU.

Email me at warfa@baldandsexy.com

first up i'm not totally sure what happens in the VTEC controller on the ECU since i'm VTEC deprived. :D

But anyway, doesn't the VTEC solenoid need to have a continous input that tells it to stay engaged? If it's tied in with the shift light, arn't you gonna upshift when it goes on, thus dropping the RPMs to below the shift point? So won't this just keep VTEC engaged for a brief second or so??? Or is the solenoid like a push switch in which case that it only needs to be on for a bit???

Does this make sense?

Hey Warfa. How do you find the Field's SFC? Like/no like? How much did you pay for it?

Fields Thingy
 

I haven't had a chance to dyno the car, but it's definately an elegent way to control the vtec engagement as opposed to a shift light, msd rpm switch, etc.

It is extremely easy to use but its very very basic. You can only adjust to fuel settings at 1000, 2000, 3000, 4000, 5000, 6000, 7000, and 8000 rpm. And at these rpm points, the fuel settings can be set at anywhere between -25% to +25% origirnal fuel settings. I wouldn't recommend it for your supercharged car cause it may not be good enough. You are welcome to tinker with mine if we ever see each other at the meets. Fields does have a website for this thing. You might want to look it up.

I got mine used from some guy in the states for 175 canadian shipped. This was almost a year ago though. I'm sure they've come down in price.

Well, you're gonna have to decide wether you want the shift light to be a shift light or a vtec controller.

You're right though, the vtec solenoid needs to have a continous signal to stay engaged. On vtec equipped ECU's, if you fall below a certain rpm (4400 i think on the SOHC vtecs), the ECU will not engage the vtec solenoid. So if you set your shift light at 4400, everytime you exceed 4400 rpm, you're light will engage the vtec. When you're below 4400, the light will not engage the vtec. But you won't be able to use the shift light as a shift light anymore as you discovered above.

Hopefully that helps.

Sweet... my VTEC-lessness meant I still understood some of it :)

I guess in that case you need those 2-stage tach's with the prewarn shift light. (you know where it lights up a whole range).

That way you can set the prewarn to activate the VTEC (at like whatever RPM), and then the actual shift light to tell you where your redline is.... heheh

mint :D