perifial port ? ? ? ?
10-22-03, 02:34 PM
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perifial port ? ? ? ?
dont mind the spelling but what is the advantage of a perifrial port, and what happens to the old intake, how much does it cost, what needs to be done to do it??
i saw a thread on this but it was far over my head
so could someone dumb it down for me 
i saw a thread on this but it was far over my head
so could someone dumb it down for me
10-22-03, 04:04 PM
#2
84SE-EGI helpy-helperton
I'll try to describe what I've read on this - keep in mind that Peripheral Port (PP) is a race-specific method for intake and isn't well suited for the street at all. What you gain in performance is way up high (over 9k rpm), and would not be usable on the street. But, if you're interested...
PP engines do away with side-intake housings and replace these with two huge holes run straight into the rotor housings that coincide with where the side-intake ports would be. This creates one huge intake port on each rotor housing, and as the apex seal of the rotor clears the port, it draws in air/fuel mixture from the PP-specific carbureator and manifold. As the next apex seal passes, it closes off the previous rotor chamber, allowing for the compression cycle of the engine.
The biggest benefit of the PP intake design is that it allows a whole lot of air/fuel to be sucked into the engine for burning and to produce more power. What you trade to get this is the inability to produce much torque at lower RPM ranges, and the extra horsepower that you generate with PP will be high in the powerband. Additionally, these engines don't tend to idle well at all due to the high overlap of exhaust and intake porting. I have read that many of them will not continue to run below 1000 rpm, at all.
PP engines were designed by Mazda racers to get much higher horsepower at the top of the rpm range which is were it's needed for road racing on long courses. This isn't a mod that you'd want to do on your streetcar, since it produces unwanted effects, including increased intake noise and drastically increased fuel consumption (to match that high volume of air going in).
It may be simpler to think of your Peripheral exhaust ports in your current engine and then imagine intake ports designed similarly. Peripheral exhaust porting works well, because it makes a direct line for the exhaust gases to be pushed out of the engine. In the RX-8 Renesis engine, the PP exhaust ports have been changed to be more like the side intake ports on our engines - this produces excellent street characteristics, good torque, and with other changes, high power output - possibly at the expense of fuel economy, however.
PP engines do away with side-intake housings and replace these with two huge holes run straight into the rotor housings that coincide with where the side-intake ports would be. This creates one huge intake port on each rotor housing, and as the apex seal of the rotor clears the port, it draws in air/fuel mixture from the PP-specific carbureator and manifold. As the next apex seal passes, it closes off the previous rotor chamber, allowing for the compression cycle of the engine.
The biggest benefit of the PP intake design is that it allows a whole lot of air/fuel to be sucked into the engine for burning and to produce more power. What you trade to get this is the inability to produce much torque at lower RPM ranges, and the extra horsepower that you generate with PP will be high in the powerband. Additionally, these engines don't tend to idle well at all due to the high overlap of exhaust and intake porting. I have read that many of them will not continue to run below 1000 rpm, at all.
PP engines were designed by Mazda racers to get much higher horsepower at the top of the rpm range which is were it's needed for road racing on long courses. This isn't a mod that you'd want to do on your streetcar, since it produces unwanted effects, including increased intake noise and drastically increased fuel consumption (to match that high volume of air going in).
It may be simpler to think of your Peripheral exhaust ports in your current engine and then imagine intake ports designed similarly. Peripheral exhaust porting works well, because it makes a direct line for the exhaust gases to be pushed out of the engine. In the RX-8 Renesis engine, the PP exhaust ports have been changed to be more like the side intake ports on our engines - this produces excellent street characteristics, good torque, and with other changes, high power output - possibly at the expense of fuel economy, however.
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