Jerry Hey wrote:

Paul,  Using a program called "InDesign" which has good photo
measurement tools I was able to determine the O.D. of the PowerSport
intake tubes which is 1.75 in.   This is also readily apparent to the
eye as the bend radius is 2.5 in which is not available  in O.D.s
larger than 1.75.   Unfortunately,  PowerSport is not able to tune the
intake length as they have no choice but to connect up to the plenum
which is completely off  the cool side.  No where else to put that.  I
estimate the total runner length from the trochoide face to the plenum
to be 26/27 inches.  Still,  they get 215 hp.

My intake will start out at a calculated length of 21.65 inches  (tuned
for 6000 rpm) and the prototype runner length will be adjustable for
fine tuning although I suspect this a bit silly. Do you agree that the
ideal tuned length of the intake runners will vary with rpm,
temperature, humidity, altitude, ram pressure?    I think Bill Jepson
was right when he stated that pressure fixes everything.

  One advantage that PowerSport has over my system is filtered air.  Our
advantage is the increased performance (15 hp?) from ram.

   Jerry

215 HP is good but 240 HP is much better.
If you are going for the expense of P-port housings you might as
well go for the gold. A good side port engine will generate 200 HP.
Also a person looking for power is going with a 2.85:1 PSRU and 7500 RPM
for climb and top speed. Tracy can barely control his RV4 on take off 
with a side port engine and a 2.85:1 gear box. As far as I know he has
yet to optmize the intake lenghts as right now they are about 10 or so
inches long. How about the size of that plenum? :)

Do what ever you want Jerry but if you want to sell P-ports housings you better
make it worthwhile.

Paul Lamar
 
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