Quote Originally Posted by silver_screen View Post
Ahhh i see, how very interesting. So you could pretty much control the lift and duration of either intake valve with these 3 stage vtecs... Both lo lobes r the same profile thou arent they?

The Nissan head doesnt seem to have the extra stages of valve control.. By the looks of the pic, they r either on or off. Only way to know for sure is to have the head right infront of me
There was only 1 D series engine with this 3 stage VTEC. And that engine, both low lift lobes were the same. So the only difference between this and DOHC vtec is that there is an intermediate 1-low, 1-high valve setting.

Quote Originally Posted by silver_screen View Post
What im sayin is that once the Hi lobe has engaged, the low lobes dont have anything more to do how high the valve will open and for long... They dont do anything for turbo spool times because its the hi lobe thats actually controlling the lift and duration of the valves... and as it seems its on both, intake and exhaust..
In low lift mode, it's purpose is to promote quick cylinder filling and efficient combustion at low RPM. So you get more exhaust gas than when compared to running high-lift mode at low RPM where you have incomplete combustion due to lower filling efficiencies from using such a high lift (bigger entrance cross-section, hence lower than optimum velocity).

More exhaust gases means quicker turbo spooling.