Bill,
What I wanted to point out is that "CFM does NOT equal HP".
This kept with just the amount of air flowing into the cylinder head.
Increasing the port size will increase the CFM (cubic feet per minute)
of air flow, but does not always translate into better performance.
So sometimes it is better to REDUCE the size of the intake port, or
modify it so the port is not a straight shot into the cylinder, but has
a bit of a curve to it. This will help promote the swirling and turbulence
in the cylinder.
A friend had a simple home made flow bench arrangement. One thing
I that was interesting was he used a plexiglas tube over the cylinder head
to simulate the cylinder. In additional to playing with the porting he
would
use a water bottle to spray mist into the port, so he could see the swirl
pattern. Also with a string feed into the port had a pretty good idea
of the turbulence induced by the cylinder head. This was over ten years
ago, and he was dead on with his "low bucks research". Air flow meter
was a simple fan (simple DC motor type which produces a voltage when
spinning - while non linear, it will allow you to make back to back
comparisons). His "vacuum source" was a couple of shop vacuum
cleaners. Heck, it was a low cost setup, but worked nicely.
Yes, the whole system needs to be balanced and tuned to a whole.
No point in having a radical camshaft profile with stock carbs and
exhaust system.
Cheers,
Tom
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