On Fri, 12 Jun 2009 13:12:48 -0500, "Tom Wait"
wrote:


"cmyr" wrote in message
...
On Jun 11, 8:06?pm, wrote:
On Thu, 11 Jun 2009 07:40:10 -0700 (PDT), cmyr

wrote:
? Going back to some hot rodding roots,I believe V.E. was increased
in the late '60's-70's thru the use of a specially designed double
cone affair placed in the collector pipe of a tuned exhaust
system,which created a stronger vacuum effect , creating stronger
scavenging of exhaust, and to some extent , helping draw more fuel/air
mix into the cylinder.

The anti reversion cone was a dirty fix for a crappy header design.
Better than a manifold, but not as good as a proper "tuned" header.

As I recall, this system was on the cover of Hot Rod magazine, on a
high end test vehicle,and was "scientifically" researched. In this
instance the reference to a crappy header design would be wrong.

All the previous 6 or7 posters have come up with methods of increasing VE
w/o superchargers. I want to add 4 or more valves per cylinder which would
probably increase the mass of the valve train. Certainly the complexity. I
don't see how a massive rocker arm or longer fatter pushrod could decrease
VE. Certainly a larger valve head would increase mass but would also
increase VE. A thicker valve stem would increase mass and decrease VE but I
think only marginally. I think the only way more mass would decrease VE
would be if the push rods were rubber.
Tom

Heavy valve trains only affect VE at high RPM - when the valves start
to float. Light valve-trains are better at high RPM, but are not
terribly effective in improving the power of a low speed "tractor
engine"