I have a p-port engine that i intend to rebuild due to insufficient power. The engine was build with lightened 9.4:1 comp rotors and is currently making 240rwh. The engine has dry sump, mazda factory pp housings, and all the required cooling and oiling mods.
My intention is to rebuild this engine using rx-8 internals such as stat gears, e-shaft, rotors, and counter weights. I heard that the rx-8 apex seal groves will have to be machined deeper to accomodate the rx-7 apex seals. Any suggestion on this setup pertaining to whether it will work or not, or should i take a different route will be greatly appreciated.

 

Your best route would be to go with a set of of lightened 9.7 rotors. You cannot get the rx-8 rotors as light as these due to the casting. Although on paper the rx-rotors are higher(static) compression in actuality the higher compression does not make up for the lost in sealing as a result of the position and design of the rx-8 side seals. You will always make more dynamic or effective compression with the 9.7 rotors and hence more power. I have not been able to make more power with the rx-8 rotors as of yet.

 

how much experimentation have you tried and have you at least matched your best S5 rotor power curve with the Renesis rotors? just curious ...

another question i have is with regard to the seal issues, how much does that affect power production on a street motor as opposed to a race motor?

thanks

 

Thanks Chris. Thats the same reply i've been getting, but coming from you it is now confirmed.