This  subject keeps coming up from time to time.
I thought we had it put to bed  years ago :)

The  p-port valve overlap is of no consequence in a  high RPM, high
power
aircraft
engine just like it was not a problem on the  1991 LeMans winning
engine and
the p-port 3 rotor engines now running and  winning in the Rolex GT
races.
These Le Mans engines had the lowest BSFC  every achieved in a rotary.

The stock side port RX8 engine has no  overlap for Hc emissions
reasons at
idle and low rpm low power typical in  automotive use.

Those engines in the Rolex GT RX8 are old 3 rotor  engines with
p-ports.

P-port engines have won many 24 hour races back  in the 1980's.

There are no apex seal wear issues as the p-port area is  a very
benign part
of the rotary. There is no pressure difference across  the apex
seals as
they
pass over the p-port. The 13B p-port hot exhaust is  far far harder on
the
apex seals than a much  cooler p-port  intake.


The RX8 side exhaust/P-port intake is particularly good  combination
as it idles as well as any 13B with side intake and p-port  exhaust.

Read:
http://www.rotaryeng.net/fund-of-intake.html
http://www.rotaryeng.net/Welded-steel-p-port.html

BTW  what is the valve overlap in a turbine engine?
The rotary comes far closer  to a turbine engine in this regard
than any piston  engine.

Paul

We drove the Pport 75 tube frame to the false grid. The Bridge
ported 95
tube frame had to be towed with a tractor. The Pport was quite docile
even
with  a 1:96 -1 first gear.

Lynn E. Hanover



Paul

Is there any specific distance from the exhaust port to the intake
P-port that has been identified other than just popping a hole in the
center of the round boss in the casting??

Is there a better optimum shape other than the round hole with the
identified size...with a position to match??

Isn't the P-port and turbo combination a match made in haven because of
the large overlap and relatively mild RPM(6000 to 7000) keeping exhaust
gases from finding there way into the intake stroke???

I know these are old questions that have been addressed probably long
ago, but I had to ask......



jeff

The proper dimension is the same as the Lemans engine.

8.64 up from the bottom.

----------------------------------------------------
Sorry Jeff I did not answer all your questions. The old ball and chain
interrupted me :)

About the turbo I have heard that said. However I have no real data
on the subject. What little I have was published by Mazda on the NA
p-port engine. Recently we took a bunch of data on the p-port
intake system pressures but we did not relate it to the pressure
in the exhaust. It is technically feasible to do that with the
equipment we have. I have just not got around to it yet. Too
busy making parts for intake systems and getting my NC mill
up and running. The next project after that is getting
the engine to run on my prop dyno and developing the 555 EFI
and the multi strike ignition system.

As far as a better shape for the p-port intake there is no
doubt one exist. I am not looking for the last few percentage points
in HP production. If one were racing one would do that.
I am looking for the cheapest way to up the HP  from
200 to 250 at 7500 RPM which a round hole in the rotor
housing achieves.

Paul Lamar


Paul

Good answer, I would agree with that.  thanks

jeff