Auxillary Ports
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Auxillary Ports
Hey ppl. I just have a simple question. I hear this subject talked about A LOT on these forums and by the way i am by no means a mechanic but striving to learn about the rotary engine as much as i can...so my question is; What are the auxillary ports, Where are they, and What do they do? What is the relation with "wiring the sixth port open" and the exaust? I feel kinda dumb asking but i figured this would be the best place to ask-Thanks!
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A 4-port engine (pre-85 NA and all Turbos) has 2 intake ports per rotor, a primary and a secondary. A 6-port motor adds an extra port called an auxiliary port. Some people call them “sixth ports” but that really doesn’t make sense! The auxiliary ports are only opened at higher rpm, which means the other ports can be smaller to boost torque at lower rpm. Basically small ports produce good low-end torque and response at the expense of top-end power. Big ports are the opposite. The 6-port system gives you both. If you understand what’s happening, you’ll see this is exactly the same principle behind Honda’s V-TEC, Mitsubishi’s MIVEC, etc.
86-88 cars use exhaust backpressure to operate the ports. A free-flow exhaust lowers backpressure meaning the aux ports may not open, killing top-end power. The common solution is to wire them open, as most people prefer to lose some bottom-end rather than top-end. The 89-91 cars operate the aux ports with pressure from the air pump, so this isn’t a concern.
86-88 cars use exhaust backpressure to operate the ports. A free-flow exhaust lowers backpressure meaning the aux ports may not open, killing top-end power. The common solution is to wire them open, as most people prefer to lose some bottom-end rather than top-end. The 89-91 cars operate the aux ports with pressure from the air pump, so this isn’t a concern.
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Dude thanks so much
And yeah it makes perfect sense to me relating to the VTEC systems and other alike
So let me ask you this then, How much back pressure do i need to keep my aux ports open?
I own an 88 N/A and have a racing pipe with a single sided N1 exaust i also have the factory header. Is there enough backpressure in my set up???
And yeah it makes perfect sense to me relating to the VTEC systems and other alike
So let me ask you this then, How much back pressure do i need to keep my aux ports open?
I own an 88 N/A and have a racing pipe with a single sided N1 exaust i also have the factory header. Is there enough backpressure in my set up???
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