Crusader_9x

i always hear everyone talking about porting and stuff and i am not quite to sure how it even works in the first place. i know how the exhaust gets out of the rotary, but how does it get in? can yall explain all the different ports and stuf to? also pictures would be greatly appreciated
thanx

richelesro

That could be a very long post indeed.

Here's some sites. If you have any questions after reading through them, post again and I can try to explain.

http://www.rotaryengineillustrated.com/RE101.html
http://www.monito.com/wankel/rce.html
http://www.howstuffworks.com/rotary-engine.htm

Crusader_9x

thanx i'll start readin

Crusader_9x

so the primary ports are on/in the center side housing and the secondarys are on/in the ends or front and back?

also is a bridge port just a really big opening but with metal there to support the seal thingy that passes over it?

so then a partial bridge or half bridge or whatever eeryone calles it is just a small or large street port on the intake and a bridge on the secondary intake?

does the exhaust port ever need any porting?

thanx

richelesro

The location of the port varies by engine version. Some have peripheral ports while others have side ports. The new RENESIS is all peripheral port, I believe.

If you look at a side port, it's a particular size and shape. Basic porting enlarges that hole so that more gases can pass through the hole. Bridge porting extends this further, but generates a problem.

Ports are restricted by the housing they are in. There are coolant passages running through all of the housings, so continued enlargement will eventually run into the coolant jacket. Bridge porting usually does a jump over a part of the coolant jacket. I'm not quite sure how it's done, but I do know that bridge ports use two ports instead of one, they're really thin, they tend to be unreliable, and are only of use in racing.

Exhaust ports can be ported to allow more gases to exit, but usually the port is not what restricts the airflow. Backpressure from the turbo/exhaust system does that. Exhaust ports are unlikely to give you any gains.

maxcooper

The RENESIS has all side ports -- intake and exhaust. Most (all?) rotaries previously sold by Mazda have had side intake ports and peripheral exhaust ports. Using all side ports brings some interesting port timing possibilities that are not possible with peripheral exhaust ports. There is zero port overlap on the RENESIS, which is good for emissions and may be good for power in this application (though usually high-HP motors have lots of overlap).

The "bridge" in bridgeporting is a narrow section of side housing that the seal can ride on so that it doesn't fall into the port. The port is open on both sides of the bridge to let air flow in. Bigger bridgeports can break through the cooling system o-ring and even take away part of the rotor housing -- these are called J-ports.

Exhaust porting does increase power because it lets more exhaust out of the combustion chamber, which means less of it is left in the combustion chamber to oppose the incoming intake air from the next combustion cycle. Rasing the roof (whoop! whoop!) of the exhaust port increase "overlap", which is when both the intake and exhaust are open to the same combustion chamber. I have been under the impression that you don't want to increase the overlap much on turbo applications, because the exhaust backpressure is high and will fight the incoming fresh air. But it seems that a lot of knowledgable people on here use huge exhaust ports, so perhaps my concern is not that well-founded. Anyone with huge exhaust ports care to comment -- is overlap a valid concern?

-Max

fastrotaries

Magic

WackyRotary

I waiting for the introduction of varible overlap ports as well as varible compression rotors, varible length headers, varible exhaust backpressure, cat-converter bypass under mid to full throttle driving to extend life of the cat's without overheating them in those circumstances when its most likely they will. Oh, and a supercharger that have varible pulleys so it give max boost at low rpm and doesn't over spin it at 8000rpm by changing the pullies diameters like on snowmobiles clutching. At least Mazda is using 3stage intake runners to help with lowend power a little. Anyway, once these technologies are nailed down, rotaries will be more fun and efficent, clean, and powerful.

Crusader_9x

thanx for all the info guys it really helped out alot