Ports? Huh, WHAT???
 

Hey .. keep seeing all these posts about porting these motors. Then I saw a pic of a 6-port turbo-ed 13B, and saw that it has 3 headers on it .. well I guess two (3 by 3 or 2 by 2 by 2, if that makes any sense, lol).

Anyway ... just wondering if that is what porting is all about. From the looks of it, it looks like a major modification for these motors, and looks real nice at the same time.

sorry man but i can't understand what you are talking about sometimes.... This engine has 3 headers on it? Perhaps your looking at a three rotor? Post a picture of this engine you speak of. Yes porting is a good modification on these cars because it allows more fuel/exhaust to enter/exit the combustion chamber... how do you figure porting looks nice at the same time? You dont see your ports, not like you can pop the hood and be like check out my ports... Its more of a performance mod then a "ewwww ahhhhh look at that" mod. You should do some searches, there is some good information about this sort of thing on this page... Theres everything you could imagine and then some

dude, turbo cars dont have headerS, no rotary has headerS, n/a can have a header, turbos have an exhaust manifold, a turbo and a downpipe..

LOL I never thought about a 3 rotor being a 6 port motor but I guess it technically is!!

eehhh, right ok. At least I'm not paying for this education.

https://www.rx7club.com/attachment.p...chmentid=89152

see what I mean? 6 pipes that go .. somewhere, looks like headers .. would that be considered a 6-ported engine?

That is a 20B 3 rotor engine. In fact, the thing with the 6 pipes (intake manifold) on top it says 3 rotor. It is hard to read but thats what it says. Hope that helps some.

On the other hand, a 6 port 13B (2 rotor) engine has 2 intake ports (inlet holes - for air and fuel mixture to enter combustion chamber) and 4 exhaust ports (outlet holes - for exhaust to escape from). A 12A (2 rotor) engine has 4 ports (most common - lets keep this simple) so it would have 2 of each intake and exhaust.

I hope that helps clear some stuff up.

I don't know what to say.... I'm dumbfounded. I usually try to be very friendly around here, but mistaking the intake for the exhaust?? Please tell me you aren't working on your own car....

Are you trying to confuse him even more? What you said is completely wrong.

The terms "4 port" and "6 port" refer to the number of intake ports only. 4 port engines have one primary and one secondary port for each rotor which makes for a total of four. 6 port engines have an extra auxillary port for each rotor for a total of 6.

All twin-rotor engines have one exhaust port per rotor except the Renisis which has two due to it's side exhaust port design.

oh oh oh who called it? Me! lol Thats a 3rotor!

And the term "porting" refers to making these ports bigger, enabling the you to suck in more air and fuel. You have probably heard about street port, bridge port, and pheripal port, the last one beeing the largest one, and a total rebuilding of the intake section of the engine.

Have a look in the engine/performace section and you should find pics of several different styles and sizes of each type of port.

Listen to RevHed, as I try and figure out something to add to make this more useful and less confusing.

Ports - Simply defined are the "holes" in the engine which allow the air/fuel to come in (intake), and the exhaust to go out (exhaust).

There is ONE exhaust port per rotor on all common rotaries (except the RX-8 Renisis which has two). Thus a 3 rotor (20B) would have 3 exhaust ports, any two rotor (12A or 13B) will have 2. The exhaust ports are NOT counted when determining the number of ports on a motor. Only the intake ports.

Intake ports - 12As commonly have 4 (some rare ones came with 6, but not in the US). 13Bs either have 4, or 6. Some models (like the GSL-SE 13B) have 6 ports. They have the standard 4 that a 12A has, but they have an additional two that are opened at certain RPMs by exhaust back pressure.

Porting an engine is simply the process of grinding these port "holes" larger to allow them to flow more air/fuel and exhaust, thus making more power.

Basically, thats a good start. I hope that helps, lol

~T.J.

PS - "Headers" are an aftermarket part of the exhaust system, and is the name of the piece that attaches to the engine and directs the exhaust out of the engine from the exhaust ports. It performs the same job as the stock piece, only better. The stock piece is typically referred to as a "manifold".

Its a 6 port, but not a 9 port :p: Although if you built one with -SE plates... Hmmm, lol :D

~T.J.

So all the porting is done through the intake? The intake has the wholes for the headers, right? It seemed that everyone would wanted to go 6-port or something, like it is a bolt on or something .. I guess .. it . could be ..... hehe

I went to a galant meet one year and this buff car dude told me that I could remove the headers off my car and use a dye grinder to make my "ports" bigger, and would result in my airflow through my headers. But I was under the impression that I would port the headers, which I think he said that is what I should do ...... but I never did it , hehe. I was gonna but the guy at lowe's didn't know what I saying and gave me a wood grinder, and thus confused my shopping for the tool even more, hehe.

I just didn't understand why there were 4-port and then a 6-port. That was another thing that got me lost. Because I did see a motor(a real pic too), that had headers like an inline 6, .. maybe it was an inline 6, lol. But it was posted here somewhere .....

Thanks for your help, peeps. I was very confused, but I now I kind of have an understanding of ports.

P.S. So you might get better airflow with a dual exhaust then? either 4 or the 6 port, right?

Porting is done with the engine disassembled and both the intake and exhaust ports are opened up using a grinder. It requires a full disassembly and rebuild to do. It cannot (well, maybe I shouldnt go that far...) and shouldnt be done any other way.

As far as exhaust headers, rotarys will only have one pipe per rotor. So, if it had 6 exhaust pipes forming a header, it most likely was NOT a rotary.

This is a header:
http://www.racingbeat.com/photos/16010.jpg

This is an intake port being street ported:
http://www.racingbeat.com/photos/22202.jpg

Keep asking, Ill keep trying to explain :)

~T.J.

Answered this. Its done with the engine disassembled, and done to both the intake and exhaust ports.
No. The cast iron plates that go between the rotor housings are what have the intake ports on them. The rotor housings have the exhaust ports on them.
Its not. It requires the physical parts that are the "block" of the engine to be changed. IE - tear it down and put different parts in their places.
Partially right, wrong way to go about it. If the engine is disassebled, you can enlarge the ports with a grinder as I showed in the picture. That would in fact increase the air flow through the exhaust, although, you need to have a good exhaust system to flow the same amount as the engine now so it doesnt become a "bottleneck" slowing it down. There are specific exhaust systems designed for the extra air flow created by porting.
Just a different design. Engines need different amounts of air/fuel at different RPMs. The 6 port engines were an attempt at making more air/fuel available to the engine at higher RPMs when its needed, and not at lower RPMs where its not because the ports open and close based on the engines exhaust back pressure which changes with RPMs.
Yes. A proper flowing exhaust system will give you much better airflow and power whether you have a 4 port or 6 port motor.

Hope that helps more.

~T.J.

Here, I made this for you, lol. This is a picture of my old engine with the intake manifold off when I was putting my Weber carb on. You can see the 4 intake ports (circled in yellow), as well as the header on the car, and the circles in red are where the exhaust ports would be under the header.

Maybe now you can get an idea of what I meant when I said the intake ports are on the iron center plates, and the exhaust ports are on the rotor housings?

~T.J.

http://memimage.cardomain.net/member...3_175_full.jpg

TOP: BTW, porting w/ the right carb (injection) mods & a header/free-flowing exhaust can make a huge difference in performance (w/out a turbo or sc). But can cost you a few ks. I've had a 12A street ported (blew that) & a 13B street ported built for my white 7 & could never go back to 95 hp.

Oooh .. a rotor housing eh? What would that be called on a 4 cyclinder? I kind of get it. I didn't know there was an actual housing for the intake and stuff. So all those intake ports do is just open up whenever airflow is needed huh? hmmm .. ...... i figured there would be a pipe to it or something, hehe.

Oh and I guess the 6-port would be visible as well like the 4 one you just showed me? So the rotor housing is like a MAIN component of the engine that gives you all those intake and exhaust goodies .. hehehehe.

But ah, yeah I guess it would require a rebuild to have the ports done, and get a ... 6-port I guess, and I guess the rb headers would be perfect for that mod. Might be a good investment. Turbo might be a little too expensive depending on what I do to it.

It would definately be a carb. It's a 12A.

The block, lol. Think of the rotor housing as the cylinder around the piston. The rotor would be the piston. The rotor spins in the housing to create combustion like the piston moves in the cylinder. The housings on either side of the rotor housing (sometimes called plates) are what seal the sides of the rotor housing. Those would be comparable to the head on a piston engine. They are what allow the air and fuel to come into the engine, like the head would on a piston engine, only there are no valves or anything like that. The rotor passing by the open port simply creates vacuum to pull the air/fuel in, and likewise with the exhaust, the rotor passing by creates pressure to push it out.
Correct. As I stated before, the rotor passing by the ports is what draws the air/fuel in, thus "opening" the port. Then after the last edge the edge of the rotor passes the port, it "closes" the port until the next combustion chamber comes by again.
The intake manifold bolts to the side of the engine where those yellow circles are, and thats what the air/fuel flow through to get into those ports. So the air comes down through the carb and mixes with fuel, then through the intake manifold, and finally down into those ports into the engine where its combusted, then expelled out the exhaust ports.
Main part, yes. Exhaust "goodies" (ports), yes. Intake "goodies" (ports) are on the rotor plates on either side of the housing. See how its kind of built in layers? The thin ones are the "plates" and the thick ones are the "housings".

Any other questions? Bring it on, lol

~T.J.

I can see the confusion here, but I had to read it about 5 times, housing for housing, hehe, and that would be called the plates. Wheeww .. man that was brain buster.

Ok, so the rotor housing is the block of the rotary engine, And the rotor that spins inside the housing pases by the 4 ports, 2 ports for one side for the first rotor, and the other 2 for the second rotor. But that seems a little confusing. Does the rotor go back and forth, and in a 360 directional vertically?(Dunno if it's clockwise or counter). Because how would that open up the ports? Like when the tip of the rotor closes the ports?

The .. uhh ... intake manifold gets air from the carb, passes the air mixing it with the fuel into the motor through the ports, and then spits out the .. uhh .. junk out through the exhaust, which the headers comes in?

man its time to goto http://auto.howstuffworks.com/rotary-engine.htm this is an awesome site with good info on how a rotary works including diagrams to show you the intake, compression, combustion and exhaust strokes, check it out you will learn alot

You DO know that these are almost nothing like Piston motors, right?

Your confusion is so severe it's confusing me

I'm sad now. :(

lol. Yeah I know, I mean especially reading from someone else's point of view on how motors work, it's hard to translate. Too bad these don't work like computers, hehe.

I looked at the manual I bought and saw a bit more on what RotorMotorDriver was talking about. Since I heard about the rx-7 I was amazed that it wasn't a pistoned valved motor. Not that I knew what all happened in a pistoned motor, but just the fact that it's a totally different engine from pretty much any car out there.

Thanks dan, that looks like a pretty good link to go to someday. I'll add it to the references for my own benefit.

It really is a good read.

I think what confused me most is your references to how a pistion motor would work. That stuff confuses the shit out of me!

My bad, I can say that it does look like that the rotary engine is easier to work on than a piston engine. I wouldn't know where to beging trying to figure out components in one of those, hehe.

Don't wait for someday, Do it today! So many of your questions will get answered by watching the .gif of the motor in action you'll question yourself on why you didn't get it the first time, lol.:D

I just looked at it, now I feel like I can put one of these together, hehe. Porting seems like cake now. Still don't understand where 6-ports come in though.

Ok, well you know where the ports are on the plates now, just imagine a second smaller port above the ones that are there on the outside two plates and thats where the 5th and 6th ports are.

Someone find this guy a picture of a 6 port plate!

~T.J.

Ok, I found some pictures for ya.

This is what a 6 port engine looks like (ignore the layup dye and outline for the street port, lol). Notice the second smaller port above the one that would regularly be there on the 4 port motor:
http://www.mazdatrix.com/faqpics/porting/6p02.jpg

This is what the valve that opens and closes it looks like:
http://www.mazdatrix.com/faqpics/porting/6p06.jpg

On the outside two plates on a 6 port motor, there are two holes, one above the other, intead of just one like on the 4 port motors. The top of these two holes is the variable open/closed intake port on the 6 port engines. This is what the valve looks like in the top hole:
http://www.mazdatrix.com/faqpics/porting/6p07.jpg

Valve closed:
http://www.mazdatrix.com/faqpics/porting/6p08.jpg

Valve half-open:
http://www.mazdatrix.com/faqpics/porting/6p09.jpg

Valve fully open:
http://www.mazdatrix.com/faqpics/porting/6p10.jpg

~T.J.

Ooooh ok, I see. It just has an extra port on the same plate. I didn't know if it was on the outisde of the block or what, looks like it's a sure rebuild if you want 6 ports. I see.

So that outlined purple around the ports, you gonna grind all that out to make one big port?

No, thats the layup dye that you just paint on, then you trace the pattern of the port into the dye, you can see the thin line for the port outline "scratched" into the dye on the very first picture.

~T.J.

Ooh, you so you made the scratch then? All you do is port the intake to match the whole from the plate, right? Just curious. Dunno if it mattered how big you made it.