Orey if this has been answered time and time again but I tried searching and could only find threads on semi pp's. I can't really tell the difference between a semi and full pp so could someone please explain?

 

sorry*

 

Peripheral port refers to a rotary with only peripheral intake ports. The stock Mazda side intake ports are filled in on these motors.




Semi peripheral port (also called combi/combo port) has a peripheral intake port (usually smaller) AND uses the stock Mazda side intake ports.




Functionally, a full peripheral port is usually used on naturally aspirated race engines as the large intake port enhances the positive attributes of intake to exhaust port overlap, the lower pressure drop from a straight shot into engine and the stronger pulse tuning from a quickly opening port.

*interesting fact* Almost every rotary manufacturer besides Mazda used peripheral port motors for their production motors.

A semi peripheral port is usually used on turbo engines as the smaller port is dynamically blocked by the rotor face limiting the negative attributes of intake to too much exhaust overlap (on a turbo motor) while gaining the other advantages listed above.

*interesting fact* Mazda's first production rotary (Series 1 Cosmo Sport 10A) was a semi peripheral port motor from the factory.

 

Whoah, fantastic response!! That really clears things up! I was wondering because the housings looked the same but I didn't see the plates! Thanks very much for the info