RightSaid fred

Valves block the hole.
The hole (the valve seat) is the narrowest point.

Fitting a bigger valve does nothing.......just a bigger valve blocking the same size hole.
It does nothing without making the seat bigger.
It's the size of the seat, not the valve that determines the flow.


If you're going to make the seat bigger to flow more air.........you can do that with the stock valve.
But only if you've got a machine shop to put the fancy cuts on the seats.


As said above........max flow is at a lift of d/4
So there's no point in lifting a valve by more than 1/4 of the diameter.


In the case of a 35 mm intake valve, max flow will be at a lift of about 9 mm.
But that's the seat diameter, not the valve diameter.

Teal2nnr

iTrader: (7)

This was very informative. Very handy formula to have.