Paul K,
I think your base assumption that the Renesis being inferior is in
error.  The Renesis does have a few advantages and some minor
disadvantages compared to the 13B P-port, but not a big deal either way
(I like both).  The OEM Renesis provides many of the p-ports advantages
without the complications and added costs.  Frankly, Id like to hear
others opinions about the relative merits of both.  Here are mine:

Advantages:  no need to go through the problems and uncertainties
of p-porting initially (can always p-port the Renesis later if you want
to), newer motor design (should offer some advantage getting parts in
the future and internal parts are already updated/improved), lighter
rotors (helps higher rpm operation), very good port area for excellent
air flow w/o modification, better idle/low speed operation than
p-port, less concern about worn engine condition, if bought used.  Im
guessing that the Renesis might be smoother running at slower cruise
speed, and maybe have a slight edge with fuel economy?  The high speed
(Renesis) design is better suited to the 2.85 ratio redrive than the
older stock 13-B's.  To me, a big advantage is quieter operation than
reported offensive p-port exhaust noise.

Disadvantages: Runs a little hotter (attn to cooling system), slightly
less top end power (if you want to operate faster than 7000 rpm
Disappointed smiley emoticon that is, and need more hp), the [p-port]
intake manifold is simpler/lighter (2 runner tubes vs 4/6) and better
suited to the simple slide throttle- but since you have to fabricate
anyway, not a big deal imho- I'll probably use a common top/side
mounted airbox w/ the Mazda throttle body and Tracy's fuel injection.
MICHAEL D PARKER


An RX8 engine can be intake p-ported and use the side exhaust ports.
Don't forget there are two RX8 engines. Four port low power
and six port high power. Paul K has a four port low power.

The P-port will generate more power in the aircraft 5000 RPM to
top RPM through out the range. In theory the p-port will have
slightly lower fuel burn. Not proven yet in aircraft. Mazda won
LeMans with a fuel limitation using p-ports.   

Paul Lamar ...No rotor no motor.

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