Paul, In your opinion, which is the better install, 20b or a 13b? I'm
building a 3500 gvw Murphy moose. Eventually I'll put it on floats. I'm
looking for about 300 to 350 hp. I am brand new to rotaries but in the last
few weeks I have tried to absorb info from many different web sites. Here
is what I think I know. The 13b would need to be far more modified; ported,
turbocharged. It would have more available parts for a rebuild. The 20b,
stock is at 280 hp. The apex seals are taller? And may not be as good as
some aftermarket 13b seals? 20b has more torque given the same hp as a 13b.
I've also read about aftermarket 3 rotor renisis builds with non Mazda
e-shafts (homemade). There are so many different variables, I was hoping to
get advice to gain knowledge to eliminate some choices. Up to now I was
vacillating between an io-540 and a m-14.
Thanks, Paul lennemann.
The apex
seals are interchangeable. For that application a 20B would be much better.
You can not have too much power for a heavily loaded float plane. Ken
Welter effectively uses NOS to get his 3000 pound Coot on the step and out
of the water in less than 10 seconds with a 2 rotor. I would use a 375 HP
P-port 20B and use NOS for a few seconds to get it on the step and out of
the water. That should give you around 450 to 500 HP. Won't hurt the
engine. Ken has burned hundreds of pounds of NOS so far.
Don't waste your time with a side port engine.
Paul Lamar
Thanks Paul. It helps to know what to focus on learning.
Paul
Read this for more background on P-ports.
http://www.rotaryeng.net/__intake.html
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http://www.rotaryeng.net/intake.html
Paul Lamar
Paul,
When you p-port the 20B, do you need to fill in the inside portion of the
side housing or do you just plate it on the outside face?
Paul Lennemann
We use a sealing plate on the outside with an O-ring.
Jeff makes those up for us. You can get these directly from Jeff.
See the bottom of the first page on the web site.
When he bores the hole for the p-port ss tube he machines the rotor
housing flat in that area.
You can fill the inside area if you wish. I would use silicon rubber.
Easy to dig out if you have a problem
BTW we have over 74,000 hits on this you tube p-port video :)
http://www.youtube.com/watch?__v=NKJ00JsnS8A
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http://www.youtube.com/watch?v=NKJ00JsnS8A
Paul Lamar
Paul,
I think he's asking what to do about the old intake ports in the side
housings. I filled mine with Devcon.
Mark S.
Cheaper silicon rubber is good for that too. You can buy it in the hardware
store or Home Depot.
Paul Lamar
Yo Paul,
What "silicon rubber" are you referring to that can be found at Home
Depot? Do you have a part number?
Mark LaPierre
Made by GE and others. Commonly called RTV for Room Temp vulcanizing.
The clear has no filler or dye. Good to 500 F.
Paul Lamar
The unused side ports are filled with an iron powder or steel powder filled
epoxy. The racers standard part was Devcon Plastic Steel. Rough up the
port bowl and runners with a course carbide bur before adding the epoxy.
Never a problem. Nothing need be added at the port runners manifold face.
The studs left behind can be used for other such as brackets or similar and
for heat shields between exhaust and intake.
The factory Periphery port came with the "D" on its back shape. Most racers
replicated the bottom (square) shape on the top with a bit of extra radius
and polish so as not to worry the apex seal as it lands after crossing the
port. Never a problem. There are some housings around from tuners like
Mandeville with huge rectangular ports with very late closing points, but
those are for shifting every time above 10,000 RPM. 10,200 RPM for
endurance racing and 10,700 for sprint racing.
If you choose to make a rectangular port face, try to keep the cross
sectional area the same or smaller than the runner tube. You want the very
highest velocity at the port face. In addition to unrestricted intake flow,
the Periphery port has a bunch of intake/exhaust overlap. So a properly
designed exhaust can generate quite a low pressure across the rotor face
which helps get the intake flow going well along before the exhaust port is
closed off. So, exhaust and muffler design is very important. Less so for
a side port engine. Much less so for a Renesis all side ports and no
overlap.
Lynn E. Hanover
That is racer high tech. The oval port with round ss tube welded gives 250 HP
at 7500 RPM and is cheap and easy to build.
Paul Lamar
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