ox sensor on sequential efi,high overlap cam....

[Gary Derian]

When lift = 25% of valve diameter, the "curtain area" of the valve equals
the throat area.  Actual flow usually increases at higher lift but not much.
A valve cannot be opened rapidly to this point and held for a while, then
closed rapidly.  The dynamics of a mass/spring system prevent this.  A valve
is first kicked open by the cam.  Then the spring tries to stop it and
reverse its direction, then the valve is caught by the closing ramp.  The
physics of this motion dictate the cam profile.  More lift/duration requires
stronger parts and or reduced life.

Gary Derian <gderian at cybergate.net>
>
>Then why don't they stop the valve at the optimum lift point, and leave it
>there longer, instead of just stretching out an existing valve lift curves
>duration, and increasing lift by doing so?? Too much work to develop a
>really unique profile for each grind??? Yep, I AM a cynic!! :-)
>