Actual Rotary Displacement Request

[scotty305]

Interesting question, Barry.

Originally Posted by RICE RACING

There are some of us who are using this kind of bespoke *aftermarket* true rotary ECU and have been doing so for a long time!

Yes there are major benefits!
Mazda racing ECUs and stock ECUs are of this type 1080 deg true Wankel cycle, it is the only way to truly look at the engine.

Otherwise you do need to do a lot of conversions to adapt all the other ECUs, not to hard to do, but most don't get it, especially when you are looking at things like control of injector opening and closing degree's etc.

Mazda stock ECUs are only capable of measuring 360 degrees of eccentric shaft rotation; since the trigger wheel is mounted on the eccentric shaft it cannot discern the difference between one rotor face vs the other three. As far as the ECU is concerned, the rotary may as well be a two-cylinder two-stroke that displaces 1.3L per 360 degrees.


In a similar fashion, you could compare a 1.3L two stroke piston engine to a 2.6L four-stroke piston engine... both ingest the same amount of air in 720 degrees, but the 1.3L two-stroke occupies less space and will weigh less assuming similar materials are used to build both engines. Is this starting to sound familiar? If I'm not mistaken, the two-stroke should have less torque at low RPM greater fuel consumption than the four-stroke. I'm not an engine expert (rotary or piston) so please correct this if I'm wrong.