I see alot of people rolling around with "ported motors", and i wonder if the ports are doing them any good, most dont feel much stronger at all. I look at the way machine shops port piston motor heads, and i know the shape of the port, not just the increased size is very important. Im wondering if the same is applied to rotaries when they are ported. Do people ever put the housings on a flow bench, or is there a certain shape as far as the port goes on the inside of the port that would make more power? I need as much info as possible from knowledgable people who have explored this.
Rob
93 RX7

 

porting a rotary is a lot diffrent than porting a piston engine.

porting a rotary is like porting a piston engine, PLUS putting in a much larger cam, PLUS putting in much bigger valves, all at once.

(If you can't tell the difference between a ported engine and a stock one - whoever ported it did a crappy job!)

 

that reply had nothing to do with my question, i am now dumber for reading it.
Rob
93 RX7 white/blue pearl
Currently undergoing haltech/T72 garret conversion

 

I've found that ported motors pull alot harder top end vs stock that run out of steam.

 

He is right though, porting a rotary is like changing the cam and putting bigger valves etc into a piston engine.

porting a rotary alters the timing of the inlet and exhaust ports, can you bench flow a larger cam in a cylinder head? not really.

In regards to flow benching a rotary, its not really like thta, you can increase the size of te port runners by a couple of mm and smooth them out, that basically is the "bench flowing' equivalant to a cylinder head.

 

I was more wondering about shape, does making it as big as possible make more HP, or does shaping come into play also?

 

the exact port timing plays the biggest factor in the increase in HP. as would be obvious having the incoming air flowing along the smoothest possible path also helps