Searched didn't find what I wanted to know. This may sound like a noob question but is the "v-tec" on the k20a3 activated with oil pressure like on the b-series?

 

There is no vtec. So oil pressure won't activate it. You only have VFT, which runs on 2 valves until 2k then all four open.

On k20a and k20a2, however, vtec is activated by oil pressure, thats why vtec doesn't kick in when the motor is cold.

 

^^^^^^yea what he saidz0rz

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by S-fiend &raquo;</TD></TR><TR><TD CLASS="quote">There is no vtec. So oil pressure won't activate it. You only have VFT, which runs on 2 valves until 2k then all four open.

On k20a and k20a2, however, vtec is activated by oil pressure, thats why vtec doesn't kick in when the motor is cold.</TD></TR></TABLE> good answer

 

From what I understand of the a3 head it operates on one intake valve until 2200 rpm while the exhaust side both are working all the time. But is the variable of the sytem controlled electrically or mechanically?

 

Yes you are correct but it seemed simpliar to say that.

All non type S and R run on 3 valve per cylinder (one intake valve) mostly. The camshaft obviously only has two profiles, not three like the type S and R (vtec lobe). Each of these lobes sits directly over an intake valve and each of these valves has an independent rocker arm. As the cam rotates, opening the valves, only one is only opened slightly and for not long at all (this is the valve that doesn't open). The other lobe is at a normal lift and opens the valve completely. At the "i-vtec" point, oil pressure locks both of these arms together an the normal lobe opens both valves and the car goes from super econmical to econmical.

So yes I lied just to be a dick, this is what actually happens.