Barry Gardner wrote:

Paul,

I was looking again at the picture of the peripheral ports you
were showing Bobby White and I was wondering about if there was
established wisdom about the best timing on the port opening on
peripheral port jobs. If I recall correctly, one of the sets of
peripheral ports shown on the picture was done by Mazda and the
other was done by Racing Beat. The timing on those is different,
or at least appear to be.

Any particular thoughts about what the tradeoffs are for timing
those peripheral ports? Better power? Better BSFC? I looked in my
Racing Beat technical catalog but all it said was that they
change the position on the turbo version to match "turbocharged
intake port timing."

My guess would be that you could open the port on the turbo
version later and still fill the chamber because you were pushing
the mixture in under pressure with the blower. But that's a
guess. And would the advantage be similar to running less "valve
overlap" on a piston engine?

I have occasionally had this wild notion that I'd like to build
one a la Powersport and see if I could run it in my car first.
Any idea what timing Powersport decided to use or what was used
on Mazda's winning Lemans car?

Barry Gardner
Wheaton, IL

Copy this port timing and pipe size. This engine had excellent fuel burn
and power. This is the Lemans engine and it had fuel left
over from its allotment after winning the 1991 24 hour race outright.
This engine in two rotor form will generate about 230-240 HP at 6000 RPM 
with two inch intake pipes about 20-24 inches long.

You won't see much low end torque, smooth running or good low
power fuel burn however. It would be interesting to put the 
butterflies down near the port like Everett did and see if it 
works in a car. 

Paul Lamar
 
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