Being that the new Mazda 16X (16B?) will be direct-injection, would
there be ANY emissions penalty for having peripheral ports? It might
provide a little internal EGR and lower HC emissions.

Having side ports in addition to a peripheral port would get in the
way of the elegant simplicity possible with a rotary. If it's possible
to do so with good port timing, a peripheral-only exhaust and intake
rotary with aluminum intermediate housings would pretty much be the
ideal experimental aircraft engine

-Chris

Well depends on what type of p-port. If it is open 100% of the time yes
there probably would be an emissions penalty. The excessive complication is a
direct result of the current draconian car environment crafted by the "I hate
cars" weenies. They would have us all living in ant hills taking public
transportation. You might as well shoot yourself or stay drunk all the time :)
See Bruce Briggs "The War Against the Automobile". We all better hope they don't
target general aviation next.

IMHO the 16B is less than ideal as it is likely not as good from a power to
weight ratio stand point than  say an all aluminum 13B. The 16X is a sledge
hammer attempt to  improve the low RPM torque and still fit in an RX8. There is
no replacement for displacement. It is the diametrical opposite to the fine AIXRO kart engine geometry.

Paul Lamar

Paul,
Larry could possibly make a wider rotor version.
Now what would be on the wish list - wide light rotor (Titanium perhaps),
wide rotor housings, thin-wall steel end housings with side to side cooling
etc,etc.
George (down under)

I would love to see wider rotors. A 16B p-port version with wider rotors would
be spectacular. I figure such a 16B would easily generate 375 HP at
8500 to 9500 RPM. With the right transmission you don't need torque.
A fast shifting Formula 1 style transmission in an RX8 with 375 HP would be nothing short of phenomenal.

Paul Lamar

Paul--regarding discussion of wider rotors and housings...in the late 1980's
we evaluated producing our own rotors and rotor housings if Mazda were to
drop the rotary engine.  That included an analysis of optimum rotor and
rotor housing width.  The analysis concluded the 13B rotor and housing were
a less efficient width for combustion at that time than a narrower 12A. So
don't know r.e. the tradeoffs of pure displacement via wider rotors and
trochoids vs efficiency diverge substantively.   Obviously Mazda has to be
mindful of production costs and bottom-line economics.  Previously it seems
Mazda took the best approach for all of us by deciding on the most cost
efficient method of producing more power by increasing the output/size via
the width of rotors and housings in the 13B rather than start with a
theoretically superior and more expensive clean sheet.  In that regard, it
is an amazing testament to Mazda's dedication to the rotary engine that they
have kept refining this little gem of an engine and remains in production
given the relatively small market and all the other the obstacles they
successfully overcame over those years.  Every other major corporation long
ago walked away from a long term commitment to the unique little engine.
It's even more amazing because when Yamamoto and his people were doing all
the breakthrough work, the engine was virtually still in its infancy in
terms of development compared to reciprocating engines.  Had it not been
Kenichi Yamamoto's little baby it would  probably would have never happened
and not be continued today.  It seems that when Felix Wankle continued
fiddling around with various optimum configurations (including optimum ideal
rotor/housings), the unsung practical heroes are Walter Froede @ NSU, Bob
Mount and the guys at Curtiss Wright but ultimately Kenichi Yamamoto at at
Mazda that really made the engine a reality. His inspiration working on
real-world combinations and compromises kept the engine in our lives in a
practical way.  Pretty amazing really.

Steve Beckham

What criteria did you use for your analysis? My reasoning is the best combustion chamber shape is a sphere. Second best is a short cylinder (most piston engines). Third best a flat square box (like the AIXRO). Fourth a long narrow rectangular box (like the 12A). This is from a surface area to volume ratio for low heat loss to the coolant criteria.

To quote Ansdale page 46 "Unfortunately this provides a long flat and thin combustion chamber with two slender tails which could have a detrimental effect on combustion under certain operating conditions." I think it does.

The AIXRO is quite a good engine for being charged cooled.

Paul Lamar

Steve Beckham,
Part of the inefficiency is the squish areas on the rotor where the flame is
extinguished. The AIXRO motor would seem to eliminate this for a large part
of the rotor surface area i.e. wide depression.

As an alternative I was wondering if it may be feasible to have a depression
covering almost the entire surface area consisting of small round
depressions interconnected by channels large enough carry the flame, without
extinguishing it.

The depressions would add up to no more than the volume of a conventional
depression, just deep enough to carry the flame front and the channels just
wide enough.
Just a suggestion!
George (down under)