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Here you will find a collection of articles about rotary engine porting. Porting is done to increase the motor’s performance. Polishing is also done after porting to smooth out the modifications. This modification is done to the intake manifold, intake ports, exhaust housings, oil galleys, and many other parts.

	STANDARD PORT Standard ports, stock ports, are best described as a compromise between emissions, fuel economy, and power. The first rotaries were freer to making power, but there was less knowledge at that time to make the most of the ports. In general it is possible to get another a ten percent increase in power though the standard port of an atmo inducted rotary engine. Modifying on a budget? Remember that all pre-1986 rotary plates and rotor housings are interchangeable - so if necessary mix and match for best results.	Estimated BHP 150hp Enquire
	MILD EXTEND PORT Mild and extended ports are very similar in specification, but a mild port is a slight increase in porting over stock. An extended port is usually slightly more powerful and a tad louder. A mild port is the first step to rotary porting. This version has been "shaped" slightly with a metal porting tool towards the upper area of the port, increasing air-flow and top-end power without creating any significant drawbacks. he advantage is anywhere up to 10% more power can be reached, with the torque range extending higher up the rev scale, you can expect around 200 hp for a Mild Port with good induction & exhaust.	Estimated BHP 180hp Enquire
	BRIDGE PORT The Bridge port uses an additional "eyebrow" opening alongside the original "modified" port and introduces the characteristic lumpy idling. Bridge ports are simply a large port that uses a "bridge" to support the rotor's corner seal, thus preventing it from falling into the port and ruining the engine. Sometimes a Bridge port will extend slightly past the trochoid surface, requiring a notch in the rotor housing, but the water seals are not compromised. Maximum power of around 260-280hp is largely dependent on the choice of intake and exhaust systems. Unfortunately for street cars, faster normally means louder. Of all the racing ports, this design is the most streetable and minimally impacts engine life. A bridge port is also the first stage where brap-brapping exhaust noise starts to become an issue.	Estimated BHP 260-280hp Enquire
	J PORT The J ported engine (also known as monster port) is as big as conventional side-plate porting can go. It is the same as the bridge port in design, but the bridged port is now fatter and extends past the face of the rotor and into the housing’s water seal / O-ring requiring the need for the seal to be cut back and filled with a metal type sealant such as "Devcon", plus, depending on the side plate used, the water gallery requires blocking off and filling on the side plate and the rotor matching. These engines have poor low end but great high end power. Idle is around 1800 rpm. Less low end power is again to be expected. One drawback of this design is that the secondary port is extremely close to the water jacket and has a very bad tendency to break through flooding the engine with coolant. People argue the J-port and monster port are the same or do get them confused, but when looked at are considerably different.	Estimated BHP 300hp Enquire
	PERIPHERAL PORT Peripheral porting is the most extreme form of rotary breathing enhancement - and it's (by far!) the loudest. Instead of conventional metal shaping with a grinder, the side ports are actually filled and completely new circular - peripheral - intake ports are fitted directly through the rotor housing and are easily identified on an engine by its tubular intake manifold. Low rpm torque, drivability and economy are completely lost but it's just the ticket for peak power - often, over 100% improvements can be gained over standard. (Note that with really good engine management, a PP can be driven on the street quite successfully - but you'll need injector end-point setting facilities and other such management features.) However, in excess of 300hp can be found at the flywheel when combined with a race intake and exhaust. In order to construct a PP, the standard side ports must be filled or blocked off somewhere upstream in the intake.	Estimated BHP 300+ hp Enquire
Reference Link: http://www.rotaryengineillustrated.com/porting/15.html