Now I'm finally confused.
I know there are 2 exhast events in one rotation of a 13B e-shaft.
Crank one by hand with a wrench.
If there are 650 CC per chamber, Would it not be 1300 CC per revolution?
And then 2.6 liters per 2 revs.
And thus equal to a 4-stroke 2.6 liter measured by 2 revs. of the crank.

Ron Freier
Vision 4-Place
13B Turbo
(still a long way to go!)


No 2.6 Liter in one rev. There are six 650cc chambers all working
together to inhale and explode 2.6 liters of air displacement.

Paul, if you allow me a comment here.

I surely think that Ron is correct here.
Each rotor displaces 650 cc or one chamber per one shaft revolution. So
far, we all agree on.
Since the Mazda engine has two rotors, two chambers are being displaced
per one E-shaft rotation or 2 x 650cc = 1,3 litre,
and at two shaft rotations it is twice that or 2.6 litre total
displacement counting both rotors.

Two shaft rotations need be counted in the Wankel engine when comparing
it with a four-stroke RPE as the RPE needs two rotations to complete the
four-cycle operation. BTW the Wankel is also a four-stroke engine.
However, for calculating its displacement that is not the issue. The
issue is the displacement at equal rpm. To compare the two, the same rpm
must apply to both, otherwise they are simply not 'comparable'.

An equivalent four-stroke, four cylinder engine would also have 650 cc
displacement per each cylinder for a total of 4 x 650 cc = 2.6 litre
that is being displaced
at its full two rotations necessary to complete one four-cycle operation
for each cylinder.

With 'displacement' we mean of course that the displacement amount, here
2.6 litre, must be going through the complete four-cycle operation, from
intake, compression, power stroke and exhaust. All four strokes must be
performed by each chamber and by each engine to account for its
'displacement'. This rule of course applies to both engine types, to the
RPE and to the Rotary. It does not matter where we begin to count, it
can be any one of the four strokes, as is apparent in the RPE where each
cylinder is a different stroke at a given time, but all four strokes
must be completed in the two shaft rotations in order to be counted as
'displacement'.

The Mazda's having two rotors and 650 cc per chamber displaces the same
as a four-cylinder four-cycle RP-engine of 2.6 litre displacement at the
same rpm count. If both engines are running at the same rpm, both engine
will displace or pump the same amount of air and they generally will
make the same hp. Therefore, the Mazda engine is equal in displacement
to a 2.6 litre RPE. Both engines displace 2.6 litres at two shaft
rotations and both do it in four-cycle mode.

I sure hope I am not muddying the water any further.

Rolf

One shaft rotation not two. The 2.6L piston engine uses 4 chambers
while the rotary uses six. Both engine fire twice per revolution.

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