A two cycle piston engine can't be compared to a 4 cycle piston engine
with the same displacement.  This leads to statemenst like "A 1.3L 2
cycle engine is equilivent to a 4 cycle 2.6L engine".  If I want to
compare the rotary to a 4 cycle engine I would say a Mazda 13B 3.9L
engine is similar to a 2.6L 4 cycle piston engine.  (That's based on
your analysis and explanations.)  A 1.3L 2 cycle engine isn't a 2.6L
engine just because it compares to that size 4 cycle engine.

Bob W.

Here's a thought stop trying to compare them period. Stop trying to
force linear motion displacment equations onto
radial motion displacments. No matter what you do it's not going to
carry over.Completely different set of  basic
motion properties..

If sactioning bodies want to weasel thier way out of allowing a rotary
engine to run heads up
with a piston engine then that's thier problem..All it is, is yet
another nod to the rotary as a better design.

Ian
BAS