I just recieved my Innovate Wide Band O2 kit (great looking kit by the way) and the auxilary input (rpm, load, etc) has it's own manual. In the manual it describes the relationship between the rotation of the rotor and the e-shaft. The e-shaft rotates - by means of a 3:1 gear - 3 times for every rotation of the rotor. They say that for the inductive RPM pickup you set it up for 1 spark = 1 RPM.

I was wondering if there would be any advantage to changing the gear ratio between the rotor and the e-shaft. Fuel economy? (less rotor rotations per e-shaft rotation). Wider powerband? Or would this be the same as changing the final drive gearing or transmission gearing?

It would seem to me that this internal gearing of the engine is unique to the rotary and was wondering if it could be used to our advantage when compared to a piston engine. For example, want a 14,000 rpm rev limit? No problem, just change the internal gearing. Your rotors would not be physically turning any faster but the e-shaft would. To get a piston engine crank to rotate faster you have to rotate the entire assembly faster. Advantage: rotary. I would guess that your limits would be determined by the limits of the e-shaft. However, if the rotors are turning at the same rate would there be a noticeable difference in force on the e-shaft?

 

yup
its geared, and changing it wouls be the same as changeing the final drive or tranny

im sure you can change it
but timing would get to be a bitch if you changed it

 

You can't change the internal gearing without having an entirely new engine geometry. Period. The 3:1 gear reduction determines that shape of rotor housing.

Equivalent would be turning an I4 into an I6 by stuffing an extra piston and connecting rod into two of the cylinder bores.

 

wwilliam54: I could see how timing would be a problem alright because the timing is done from the crank angle sensor.

Kenku: I don't understand how the turning of the e-shaft is related to the shape of the rotor housing. Can you elaborate? If we put a gear with a different gear ratio into the engine wouldn't the rotor rotate through it's phases as normal?

 

No, because the internal gears (ring gear on rotor, teeth in; stationary gear on housing) are what keep the rotors properly "clocked" in the housing. If you changed those the rotors would no longer have the same TDC, BDC, etc..... you would need totally new everything.

I thought about this once and I came to the conclusion that the current setup is the best.