Mix/Match porting?
10-26-04, 03:35 AM
#1
Mix/Match porting?
I was wondering if you can mix and match porting.
Example: Half bridge (exhaust bridged) and peripheral intake. Maybe even large street intake and bridge exhaust? What about mild street intake and large street exhaust? Ideas a buddy of mine and I were coming up with.
What about a half street? Just street the exhaust...
Ideas, comments appreciated
Also BTW, not too sure about porting specifics. Kind of an all around noob, so take it easy on me.
Example: Half bridge (exhaust bridged) and peripheral intake. Maybe even large street intake and bridge exhaust? What about mild street intake and large street exhaust? Ideas a buddy of mine and I were coming up with.
What about a half street? Just street the exhaust...
Ideas, comments appreciated
Also BTW, not too sure about porting specifics. Kind of an all around noob, so take it easy on me.
10-26-04, 05:52 AM
#2
Savanna Rx-7
whatever works
I have always stuck wit thematching ports, but its been said before, there are a million ways to do it, and none of them are wrong, just some work a little better.
I would think that a race exhaust port but not going quite as high on the rotor housing wall (limits overlap) and then posibly a very large street port contoured properly might work (bridges crack eventually) but you might lose some low end as a result thats one thats totally safe, cause if you don't like it you can always finish the exhaust housings, and then bridge port it and end up with about 230~250 hp depending upon how you tune your ignition and carb Side ports are what around 200~220 right now? something in the middle might be nice little lopey but not crazy?
And BTW bridge or peri are reffering to the intake side as the exhaust is already a peri port (except rx-8 engines) you simply change its (exhaust) size and location and as a result it changes your exhaust timing kinda like changing your cam out to one with a little more lift and duration. The intake on the other hand is raisded up so it stays open a little longer kinda hard to describe a bridge if you don't know what the inside looks like to start with, but if you can imagine this: the triangular face of the rotor is moving upwards and as it uncovers the port, air and fuel vapors enters/fills the chamber. due to the location of the corner seals if you open the port to wide, the seals will fall out, and you are minus an engine, so you leave a small ribbon or (bridge) exactly where the path of the corner seal runs, this keeps the seal from falling into the port. a side port is the same you change the port timing but you don't take it far enough to require the bridge. A peri port on the other hand is a totally different animal as it radically changes you intake exhaust overlap, and timing with a perry port you make a full race exhaust port, and then you fill, yes grasshoppa you fill the intake ports up with devcon plastic steel, and then you bore a hole through the rotor houseings water jacket and thread a pipe into it. contour the ends of the pipe, hook a carb on the other end and walla a peri port
now this is an extremely oversimplified explanation as there are many more mods to make before doing a bridge, or a peri as stuff like your oil pump, bearings, and many other odds and ends need to be modified to handle the extra strain going the cheapest route is of course the street port (called a side where I am from) as the stock internals will function fine and dandy with them, and its also the easiest to drive on the street power band is raised a bit, but not overly so a bridge or peri starts making power way later in the power band, kinda similiar to turbo lag, but just like the turbo they make gobs more power
ken
I would think that a race exhaust port but not going quite as high on the rotor housing wall (limits overlap) and then posibly a very large street port contoured properly might work (bridges crack eventually) but you might lose some low end as a result thats one thats totally safe, cause if you don't like it you can always finish the exhaust housings, and then bridge port it and end up with about 230~250 hp depending upon how you tune your ignition and carb Side ports are what around 200~220 right now? something in the middle might be nice little lopey but not crazy?
And BTW bridge or peri are reffering to the intake side as the exhaust is already a peri port (except rx-8 engines) you simply change its (exhaust) size and location and as a result it changes your exhaust timing kinda like changing your cam out to one with a little more lift and duration. The intake on the other hand is raisded up so it stays open a little longer kinda hard to describe a bridge if you don't know what the inside looks like to start with, but if you can imagine this: the triangular face of the rotor is moving upwards and as it uncovers the port, air and fuel vapors enters/fills the chamber. due to the location of the corner seals if you open the port to wide, the seals will fall out, and you are minus an engine, so you leave a small ribbon or (bridge) exactly where the path of the corner seal runs, this keeps the seal from falling into the port. a side port is the same you change the port timing but you don't take it far enough to require the bridge. A peri port on the other hand is a totally different animal as it radically changes you intake exhaust overlap, and timing with a perry port you make a full race exhaust port, and then you fill, yes grasshoppa you fill the intake ports up with devcon plastic steel, and then you bore a hole through the rotor houseings water jacket and thread a pipe into it. contour the ends of the pipe, hook a carb on the other end and walla a peri port
now this is an extremely oversimplified explanation as there are many more mods to make before doing a bridge, or a peri as stuff like your oil pump, bearings, and many other odds and ends need to be modified to handle the extra strain going the cheapest route is of course the street port (called a side where I am from) as the stock internals will function fine and dandy with them, and its also the easiest to drive on the street power band is raised a bit, but not overly so a bridge or peri starts making power way later in the power band, kinda similiar to turbo lag, but just like the turbo they make gobs more power
ken
Do a quick serch Ian
10-26-04, 08:04 AM
#4
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you could bridge the secondary's and street the primarys.... I wanted to do that to a 12a and fuel inject it at one time....... now I want to pp my 13b and boost it with efi...... Now if I can finish putting together the rest of the car and live with the 13b street port till I gather the rest of the parts I need...
humm.... a brap brap brap but with the low end of a street port and high end of a bridgey..... well.... closer to each.....
Porting depends on your driving style.....
humm.... a brap brap brap but with the low end of a street port and high end of a bridgey..... well.... closer to each.....
Porting depends on your driving style.....
10-26-04, 08:26 AM
#6
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everyone wants a PP. the closet most of us will get to a pp is after drinking a few cups of coffe 
sorry i'm board.....
i also thought of kicking around the idea of a PP still having the stock ports, and at low rpms the pp s closed and once it gets past 2200rpm then the pp would open up like wammy!!
sorry i'm board.....
i also thought of kicking around the idea of a PP still having the stock ports, and at low rpms the pp s closed and once it gets past 2200rpm then the pp would open up like wammy!!
10-26-04, 09:08 AM
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yea, that would be cool.... but more hassle than its worth.... I was thinking about that a while back myself, then these kind folks on here set me on the right track, lol...
with a peripheral port, you can tune it for a street engine... and use stock everything.... except for the intake part of course..... I just wish I knew what each port timing on a pp did and what size and all that..... I dont want to guess at the port I want, I want to have the port I want....
Later, Andrew
with a peripheral port, you can tune it for a street engine... and use stock everything.... except for the intake part of course..... I just wish I knew what each port timing on a pp did and what size and all that..... I dont want to guess at the port I want, I want to have the port I want....
Later, Andrew
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10-26-04, 10:23 AM
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what about a different port on each rotor.. so one rotor gives you some decent low end grunt, while the other keeps pulling at high revs, with a super sweet spot in the middle...
its be really hard to set up and tune..
but say it was set up and tuned well.. would it work? or would the motor be off ballenced and die?
just curious
its be really hard to set up and tune..
but say it was set up and tuned well.. would it work? or would the motor be off ballenced and die?
just curious
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