Rotary Engine Porting

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.

A bridge port is simply a diluted version of a J port and makes roughly 10% less power - but with slightly better bottom end torque.

Since the port goes all the way out to the trochoid surface, there is significant overlap with the exhaust port, reducing low-RPM power in favor of significant power gains in the high-RPM range (5,000+). The improved air-flow increases top-end power dramatically with a noticeable power-band peaking around 8,000rpm while drivability, smoothness and fuel efficiency is reduced.

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.

PRO'S: Very good potential for power, increased rev-range
CON'S: Poor drivability, fuel consumption and excessive noise