The big problem making intake manifolds for the rotary
is the short distance from side ports to the top of the
engine. This has been a problem from day one. We addressed this
problem years ago by making a casting for the second gen
engine that could be welded to 90 degree bends that
took the manifold up and over the top of the engine.
Been there done that. See cut down lower 2nd gen four
port in the mill jpg. Note the lack of round interfaces
to the round tube.

The problem has reemerged for the RX8 engine.
the lower part of the RX8 six port manifold is more
suitable for cutting and welding than the 2nd gen manifold
because the runners are closer to round.

That is the good news.

Problem is most thin wall tubing bends use a 3 inch radius
minimum which is not tight enough. The tubes wind up too far
above the rotor housings. There are weldable aluminum bends out
there with tighter radii however. That is why and when I discovered
RB Wagner. See the Wagner cat in jpg form. These are "pipe" bends
and not tubing bends. There is a difference. Pipe comes in different
sizes and is usually thicker wall adding to the weight. That is
the only drawback. They are actually  easer to weld to castings
however.

The last jpg one is Bill Schertz 2nd gen version built with the ACRE
NL casting. Unfortunately these are all sold out but the demand
is now for the six port RX8 engine anyway.

There is another alternative and that is coming straight
out of the side of the cowl with a ram air scoop on the
end of a round plenum. I'll do a 3D shortly of that shortly.

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We used to call this the Shaker Hood Scoop back in the 70's
when it was used on the Pontiac Trans Am. It was also used in the
P38 and most German fighter planes back in WW II.
Place the slot for it around the cowl split line.

The tubes are probably about the right length if you are
going to run the RX8 engine at 8500 RPM and about 240 HP
with a smaller prop and a 2.85:1  one gear box.

A regular butterfly can be used or what is even tricker
is a barrel valve throttle for a little more air with the
same diameter plenum/scoop.

Only two four tubes are shown in the 3D but the RX8 has six.
The four front and rear ports on the RX8 engine are round so
no transition problems. More good news. The two center
ports are still oval so you will need an oval to round transition.
Not hard to make in sheet metal if you have the right flat pattern.

Paul Lamar

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