"peripheral port right from the get go" begs the question: Since the p-port
provides so much extra power, why doesn't Mazda use them?  Does the BSFC
suffer or is there something more important?  In any case the compound
turbine will more than make up for any possible loss in BSFC!

Norm

Mazda used them in the Lemans engine and got a BSFC of .47. That is about the
lowest ANYBODY has been able to attain out of a
Wankel rotary so far and they were not running it super lean. They won the race
outright in 1991 over all on a race fuel limit running against who's who in
international car racing. ONLY Japanese company ever to win Lemans.

Mazda current rotary engine development is primarily driven by two things.
Low speed/RPM torque and emissions. Low speed/RPM torque is the only reason
for the extremely complicated RX8 engine intake manifold. P-ports are not
the best for low speed/RPM smooth running and emissions.

Paul Lamar

Unlike previous models, the RX-8 engine has no ports on the perimeter.
The side intake and exhaust ports on the RX-8 are likely a contributor
to the flooding problems. No port on the perimeter to sling the excess
liquid out of.

One would assume that the apex seal lube oil, injected from the
perimeter, behaves in the same way. This would reduce the amount of oil
in the exhaust, and also the amount needed to be injected. Thus, the
hydrocarbon emissions would be reduced. I'd guess this is the motivation
to move the exhaust ports to the sides.

    The P-port would allow the apex lube oil to sling out. You would
probably need to inject more, and more would get entrained in the
incoming air. If true, this would increase hydrocarbon emissions.

    I wonder what would happen if you were to move the ports to the
perimeter on an RX-8 engine.

Bill Dube'

Mazda wrote an SAE paper on the side port engine.

Shimizu, Ritsuharu et al. "Characteristics of fuel consumption and exhaust
emissions of the side exhaust port rotary engine"
Proceedings of the Future Transportation Technology Conference and
Exposition, Costa Mesa, CA, USA. Futuristic Concepts in Engines and
Components SAE Special Publications n 1108 1995. SAE, Warrendale, PA,
USA. p 181-188   SAE 950454.

It is not so much the lubricating oil that is the emissions problem.
It is the over lap between intake and exhaust that destabilizes
combustion at low speeds causing the engine to misfire at low RPM.
Every Mazda engine from the beginning would miss
fire periodically at idle with the results of a huge dollop of unburned
hydrocarbons went out the exhaust.

The RX8 engine is remarkable in the fact that it can pull away from a
stop without your foot on the accel pedal by merely releasing the clutch.
In other words it pulls from low RPM without stumbling. Not very fast
I might add.

Paul Lamar ...No rotor no motor.

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