While that is happening, the exhaust port is still open and blowing some exhaust gas out, and we can still have some residual exhaust gas pressure above atmospheric. They will have a very rough idle, nothing below 1500 rpm, with around 1800 rpm more suited. They are still very streetable and deliver very good power. Normally a 3 day turn around to get engine done from date of purchase, if longer a longer wait will occur, we will notify you at time of purchase. Aside from adding a turbo or supercharger to a rotary engine, the only other way to increase performance is by porting the intake section of the engine.
Limited clearance on the Renesis side housings creates additional challenges when porting these housings, our instructions provide detailed photos of the most critical areas of concern. Fine, but there is also a chance that there is still some exhaust gas lurking in the intake port s as a result of the overlap so that poor old chamber still can't pull a completely clean intake charge. This is a bit of an unfortunate tradeoff, though, since the lack of overlap limits power potential and the location of the the exhaust port makes its difficult to increase duration. This is also quite true for piston engines. Recommended for race engines only, the purpose of bridge porting is to add up to 165° of additional intake duration.
So, to my mind, based on this, the best way to increase exhaust gas velocity is to encourage as fast port opening as possible to encourage sudden pressure drop - ie to keep the beginning of the port flat - this would increase exhaust gas velocity, but also noise. The J-bridge port design requires us to cut away material on the rotor housing also. Alternative 1 - The whole Cylerindical Shape of the rotary Ex port seems to be totally wrong in comparison to a pistons. Included with the Renesis porting templates are Racing Beat's exclusive detailed instructions and advice to guide you through your porting efforts. These engines need a good open exhaust and lower gearing ie. Some low down torque is lost but mid to high range is much improved. The finished template is held in place and the porting shape is then traced onto each housing.
A more aggressive or large street port takes this same basic approach a bit further, by enlarging the existing ports more and extending their shape as a way of increasing duration. Bridge Port - The next step in porting is the Bridge Port. These templates are traced from Racing Beat's own master templates, which are the result of years of research and development. So street porting on the aggressive end of the spectrum can start to hurt street-friendliness a bit, but is still considered a good compromise between performance and everyday drivability. There are a couple of different types of Bridge Ports, the first being to keep a relatively stock primary port, then cut a secondary port above this, the metal bridge left between the primary and secondary ports is how these engines get their names.
Included with the Renesis porting templates are detailed instructions and advice to guide you through your porting efforts. Within this forum regular users will not be able to post new topics. The Extended Bridge Port is exactly what it sounds like, running an extend primary port with a secondary port cut to match. If you think of it in terms of combustion chamber pressure, with a peripheral exhaust port, the port opens suddenly, which causes pressure to drop rapidly. I just did it to try it basically and now I would not go back to a small port exhaust. As a result, power gains tend to be modest but not insignificant with this type of portin 10% gained over stock power is a pretty common estimate for a street port.
On Renesis engines the exhaust port is on the side iron, but on all other versions of the 13B and 20B the exhaust port is on the aluminum rotor housing, as seen here. A turbo rotary engine can also receive a porting along the lines of a mild or extend port, bridge-porting a turbo motor is possible, but it is uncommon due to overlap. I would assume this would work well on paper, As i have yet to see any Proof of this being better then the stock Peripheral port style Ex ports. Unlike other templates, the holes are already cut for you. The half bridge is when the additional eyebrow port is only cut above the secondary intake on the side housing, while the primary port is just street ported.
When the rotor is opening on the intake stage and there is lots of overlap with exhaust opening, from where would that chamber find it easier to fill the space? If a core is unavailable,core charge will be added to the engine build. Cost for J-Bridge Porting Same as Standard Bridge Above. Limited clearance on the 6-Port Renesis side housings creates additional challenges when porting these housings, our instructions provide detailed photos of the most critical areas of concern. A decent Extend Port is near double the size of the stock port and will produce up to 240 hp, possible more. Argument - The factor that gives rotary engines inherently fast flowing exhaust gas is the peripheral exhaust port. Idle is around 1800 rpm. First I'll explain of where the ports are situated in a Rotary Engine.
I myself havent heard of this being practised much as the origonal 2 inch ports flow considerably well and also match up nicely with the 2 inch primarys in the exhaust system that u have made to suit your port, as a high exhaust velocity is reccomended when building a system so consistant diameters in tubing do pay. The port size at the face of the rotor housing cant be too big, as that would either make the port open earlier, losing alot of combustion pressure, or stay open longer, giving alot more overlap, and causing the rough idle of a big ported motor, but without the extra power. The Racing Beat Intake Port Templates allow you to undertake your own standard bridge-port efforts on any 12A or 13B rotary engine except 13B 6-port. Porting templates are where even the most experienced builders started. When the admin spot a topic that they think is worthy of saving they will move it into this forum. 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. The shape of the inlet varies from a Circular shape to a 'D' style shape.