Here are my calculations on the size of the port tubes 
required based on the six port drawing Mike Wills sent me.

The big hole on the six port part of the end housings is about 
0.95 square inches and the little one about 0.785 square inches. 

A = pi X r squared.

That totals about 1.735 square inches or about a 1-1/2 inch ID 
round pipe.

I think more can be done porting six port engines by taking out 
the web between the two holes. Now I don't want to hear from Joe 
Blow who tried that in his car and it did not work. It has got to work at 
5000 RPM and above. We are not drag racing here. If for no other reason 
there is less skin friction with one hole than two and not to mention that
you will gain port area. Sure the bottom end might go away but who cares. 

If you do that you probably can use a 1 1-3/4 inch ID tube in these
positions.

On the center housing the area of each oblong hole is about 1.35 
square inches so about a 1 3/8 ID  round tube is called for. 
Perhaps with a little porting you could get those holes up to the 
area of a 1 1/2 inch ID tube. 

BTW the circumference of these round tubes
when shaped to an oblong to fit the port will be less than the
circumference of the port itself so the tubes must be cut and small
triangular pieces welded in the long way to properly transition 
the tube from round to oblong. Drawing at 11.

Probably easier to make a peripheral port and be done with it :-).

In any event these tube sizes are pathetic for a NA rotary.
We should be running 2-1/4 or 2-1/2 inch  tubes with peripheral 
ports for NA engines.  Again, one tube has less skin friction
than two of the same area not to mention the fact they have greater
total area. Turbos matter less as you just crank up the boost 
a bit.

Let me know what you guys want to do. All comments highly appreciated
on these tube sizes.

Paul Lamar
 
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