CoupeM

Is there any out there in the market right now? Say 11 or 12:1 compression?

rotarygod

The Renesis rotors are almost too high in compression ratio right now. That's because each rotor face has a dish or indention. The size of this dish determines the compression ratio. The dish is quite shallow on the Renesis rotors as compared to the lower compression counterparts. This unfortunately effects airflow through the engine worse than changing compression does on a piston engine as the air needs to pass through this spot and keep going around the engine. On a piston engine the air essentially stays in the same place and just gets squished and expanded. Combustion characteristics are altered somewhat on the rotary since the air has to pass this small area rather than stay there. Mazda did tests years ago that found that any compression ratio between about 9:1 and 11:1 yielded the same power levels. Higher or lower than that and power would go down. Above 11:1 power would fall off as the dish space was too small for good combustion and flame front travel and below 9:1 power falls off due to a lack of compression. Mazda has changed it's "high compression" rotors over the years from 9.4:1 to 9.7:1 to the current 10:1 with no apparent explanation. Only Mazda makes rotors. No aftermarket company does. There is no power to be had from going higher and you only risk the onset of detonation earlier.

ShadowX

Go lower and get boost. End of story

Sorry, I know you didn't ask that, but that's how you make power in a rotary.

CoupeM

ok...i was thinking of how to squeese as much as possible if i go all motor.