New details are coming out about the RX8 engine.
May Sport Compact Car magazine had a rather comprehensive
technical article on the engine.
There is a new seal on the rotor called the cutoff seal.
What this does is prevent communication between the side intake port
and the side exhaust port along the sides of the rotors.

The engine weight is given at 273 pounds with a 14.75 pound flywheel,
(3.7 pounds less) starter, alternator and AC compressor I think. This also
includes a rather elaborate plastic intake manifold system.

I wish I had a copy of this illustration that I could read.
One cannot read the original published in the magazine either.

The intake system is extremely elaborate to
say the least in an attempt to broaden the torque curve.
Mazda should forget it and just install a supercharger. 

The exhaust ports on the center housing are siamezed(s?) so
tuning those ports is probably out. The end housing exhaust
ports could still be tuned but with less overall effect
on the HP. The noise it makes is much less than the old
engine and the exhaust is much cooler.

The rotors are now down to 8.6 pounds from about 9 to 9.5 pounds.
The main reason the red line is now 9500 RPM. Compression ratio
is up from 9.2:1 on the twin turbo to 10:1 on the new RX8 motor.
That will be a problem for anybody wishing to turbo charge unless
Mazda does some light weight low compression rotors.

The new EFI/IGN system uses a wide band O2 sensor and a hot wire mass
airflow sensor that will accommodate intake system changes better
than the 3rd gen engines. The old system used speed density.

There are six fuel injectors instead of only four. There are also
two oil injectors per rotor housing instead of only one and
half the oil per mile is required to lube and cool the apex seals.
The apex seals run cooler. Old apex seals ran at 500 degrees because
of the peripheral port exhaust. In fact if you over do it mixing oil 
with the fuel you might carbon up the exhaust ports. I am not sure if
that applies to mixing two cycle oil with the fuel.

Paul Lamar
 
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