short rod has more dwell at BDC allowing you to keep the
intak open a couple degrees longer (allowing intake inertia
to do some more work instead of just compressing itself
against a closed valve).


I don't know if you misquoted, but the long rod will have more
dwell time at TDC and BDC. I think everyone is missing the
point with this engine. The RPM gains are a minimal advantage
to the long rod and the torque to the short, the reason you
build a long rod engine when you can is to relieve side load
on the cilinder wall, and transfer more of the energy down the
centerline of the rod as opposed to diagnally across it. I
have pulled many of the same race engines apart with the only
difference being the R/S ratio and rod length and you can see
the difference in the cilinder walls and piston skirts. To
visualize this draw a tall letter I and a short letter Z. The
two horizontal lines are the piston and the crank, the two
vertical lines are the rods. Even with the longer vertical
line in the I, which vertical line do you think will bend or
break first. my example is a little exagerated but I wanted
everyone to get the point. Everyone was getting a little to
far in the wrong direction. As far as the long rod turning
more rpm because of the decrease in piston speed, that benefit
is minimal. The reason the long rod can turn more RPM is
simply because it can phisically do it without breaking parts.

Just my 02
Nick