the prob here is dat u take "advance" and "speed up" to mean the
same thing, jumble up ur explanation of how it works in cam
phasing, and pretend that it was juz a wrong choice of words?
dats interesting. "cam change is a technique of valve varying".
now tell me, how does changing ur cams equate varying of valves? in
the first place, ur valves cannot vary. only the amount of LIFT is
gets can vary. vtec cam lobes do not increase. u think magic ah? at
the correct load and rpm, a set of pins lock the rocker arms so
that the big lobes take over the timing. "cam lobes increase in
length" dats real funny u know? 
errm, hello? lost sheep? u dun turn the cam in the opposite
direction how to retard it? if u have to "slow down" a cam in order
to retard it, are u saying that u gotta slow down the whole engine
in order to retard that cam? cam phasing is all about altering the
cam angles relative to each other in order to achieve overlap via
advance (turning cam forwards) and retard (turning cams backwards).
got the cheek to tell me "retard is to slow down"? looks like ur
"basic concept" of an engine is really retarded. 
so how does overlap help to improve FC and torque at lower
engine speed? more overlap better or less overlap better?
you need to have some humility when u talk rot blindly. until
then, u'll deserve none of the treatment worthy of other
forumites
