Why does a rotary engine make as much power as a boinger twice its size?
There are lots of reasons, but the main one is that a “2292 cc” piston engine isn’t actually twice as big as an 1146 cc 12A Mazda rotary. That’s right! The following comparison of a Pinto engine to the 12A explains why. A 12A feeds two power cycles into the eccentric shaft for each revolution it makes. Each rotor face displaces a volume of 35.0 cubic inches, which is 573 cc. Therefore, 70.0 cubic inches or 1146 cc’s worth of power are delivered to the output shaft for each revolution that shaft makes. The most common Pinto engine is a 4-cycle, 4 cylinder, having four pistons that each displace 35.0 cubic inches or 573 cc. Exactly two of these four cylinders deliver power to the output shaft in one revolution, which just happens to be exactly the same 70 cubic inch or 1146 cc amount as a 12A is doing in the same amount of time. A key point here is the element of time. We measure engine size with reference to two things: time, and output shaft movement, revolutions per minute, or RPM. To
