How do you port a motor?
wow, I never knew about j ports or peripheral ports. My FC is a daily/soon to be drifter as well so that 1/2sp 1/2bp idea sounds like the best of both worlds. I have to rebuild a T2 engine I inherited from when my brother got his 7 plus a bunch of extra stuff so I am swapping my N/A.
Could you go into more info on the fuel setup? I am a noob on that part, you have to get rid of the EFI and go carb right? I don't know about that aspect. Is there a way to keep the EFI or would it not be able to run like the streetport daily, bridge performance driving and run bridge all the time.
I was thinking medium streetport because I could use OEM rotor seals. with 1/2sp 1/2bp I would have to upgrade the rotor seals to what, ceramic which are like $1000 or more for just apex seals? can't afford that right now. Like I said, more info would be a great help, thanks.
Could you go into more info on the fuel setup? I am a noob on that part, you have to get rid of the EFI and go carb right? I don't know about that aspect. Is there a way to keep the EFI or would it not be able to run like the streetport daily, bridge performance driving and run bridge all the time.
I was thinking medium streetport because I could use OEM rotor seals. with 1/2sp 1/2bp I would have to upgrade the rotor seals to what, ceramic which are like $1000 or more for just apex seals? can't afford that right now. Like I said, more info would be a great help, thanks.
To be effective, one should start with the 4-port TII engine. Using 2 Tweak-It kits may have potential also but designing/building the intake and staged linkage would be a nightmare challenge.
Thread Starter
Junior Member
Joined: Mar 2009
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From: Springhill FL
That almost seems to defeat the purpose of porting the motor in the first place gonna make it bigger and that sleeve will choke it down.
Also so what your saying is that if I was to remove those sleeves then i would need to upgrade my cooling system? So my motor dosnt overheat.
Also so what your saying is that if I was to remove those sleeves then i would need to upgrade my cooling system? So my motor dosnt overheat.
I know nothing! Help me!?
Joined: Apr 2007
Posts: 446
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From: New Hampshire
Full Bridge
Ok So what I am gathering from this very informative thread that if I wanted to run a full bridge on my 83 witha 12a I would have to run supporting mods like a larger carb as the nikki would not keep up with the new airflow and other supporting mods like intake and full exhaust (headers,pipes) ?
I am JUST getting into the 1st 7s I had 2 2nd gens so I am a carbed 7 newb
I am JUST getting into the 1st 7s I had 2 2nd gens so I am a carbed 7 newb
That almost seems to defeat the purpose of porting the motor in the first place gonna make it bigger and that sleeve will choke it down.
Also so what your saying is that if I was to remove those sleeves then i would need to upgrade my cooling system? So my motor dosnt overheat.
Also so what your saying is that if I was to remove those sleeves then i would need to upgrade my cooling system? So my motor dosnt overheat.
Ok So what I am gathering from this very informative thread that if I wanted to run a full bridge on my 83 witha 12a I would have to run supporting mods like a larger carb as the nikki would not keep up with the new airflow and other supporting mods like intake and full exhaust (headers,pipes) ?
I am JUST getting into the 1st 7s I had 2 2nd gens so I am a carbed 7 newb
I am JUST getting into the 1st 7s I had 2 2nd gens so I am a carbed 7 newb
It depends on how hardcore of a port you are wanting to get. A small bridge with 8K redline will not make as much power as a huge bridge at 10k, but will cost MUCH less.
A big bridge motor with a high RPM band you will start needing to balance the rotating assembly, carbon/ceramic apex seals, modified Oil pressure regulators, hardened stationary gears, clearance the rotors, etc. It all starts to add up to mucho denero. At that point you might as well just go PP.
That almost seems to defeat the purpose of porting the motor in the first place gonna make it bigger and that sleeve will choke it down.
Also so what your saying is that if I was to remove those sleeves then i would need to upgrade my cooling system? So my motor dosnt overheat.
Also so what your saying is that if I was to remove those sleeves then i would need to upgrade my cooling system? So my motor dosnt overheat.
I thought the only purpose of that metal thinggy was to reduce the harmonics of the rotary exhaust...in other words just for improving the sound (thrash) of the engine.
Is this what you are talking about or is it another metal object?
Guess you guys got me a little lost here....are you talking about the metal sleeve that is in the exhaust port of the FC 13b NA motors???
I thought the only purpose of that metal thinggy was to reduce the harmonics of the rotary exhaust...in other words just for improving the sound (thrash) of the engine.
Is this what you are talking about or is it another metal object?
I thought the only purpose of that metal thinggy was to reduce the harmonics of the rotary exhaust...in other words just for improving the sound (thrash) of the engine.
Is this what you are talking about or is it another metal object?
so is the baffled sleeve on the exhaust port there for heat reduction or just to help tone down the resonance! If 12a's don't have it then I'd assume its just a luxury item that you could do without. the 13b port is larger but thats only because its in proportion to the rest of the engine. a 12a is slightly smaller so smaller exhaust port. BUUUUUUT, maybe the 13b makes more heat then the 12a so mazda needed to put that in...
I'm talking myself in circles, someone set me straight so I can learn how this whole thing works!lol.
I'm talking myself in circles, someone set me straight so I can learn how this whole thing works!lol.
so is the baffled sleeve on the exhaust port there for heat reduction or just to help tone down the resonance! If 12a's don't have it then I'd assume its just a luxury item that you could do without. the 13b port is larger but thats only because its in proportion to the rest of the engine. a 12a is slightly smaller so smaller exhaust port. BUUUUUUT, maybe the 13b makes more heat then the 12a so mazda needed to put that in...
I'm talking myself in circles, someone set me straight so I can learn how this whole thing works!lol.
I'm talking myself in circles, someone set me straight so I can learn how this whole thing works!lol.
"The 1986-92 6-Port non-turbo engines employed steel exhaust port “splitter” sleeves in the rotor housings to both reduce the heat transfer from the exhaust gas to the rotor housing and initially reduce noise by breaking up the exhaust gases as they leave the combustion chambers in advance of entering the cast iron manifold. For street use, these splitters offer no significant reduction in power and can remain in place; however, for racing applications, we recommend that these splitters be removed with a grinding tool while leaving the steel sleeves intact, or you can use the turbo rotor housings - these do not contain exhaust splitter sleeves.
Mazda’s turbocharged engines do not require exhaust splitters because the turbocharger is very effective in reducing exhaust noise, but these engines are equipped with a steel sleeve in the exhaust port to reduce heat transfer from the exhaust gas to the rotor housing water jacket. In our experience there is no significant horsepower benefit gained from removing the sleeve in either street or race applications. Furthermore, retaining the sleeve allows a better match between the rotor housing and the exhaust manifold. If you should hear a rattling noise coming from the engine, usually just off idle, a possible source of this noise is a loose exhaust port sleeve."
if u've ever seen the other side of the port with that insert removed i'd say that removing it would create more turbulence on the header side. removing it makes a huge *** hole on that side.
So if I port the exhaust ports bigger, do I have to make some new sleeves that would fit the port or is there enough material on the sleeve that I could just grind that down to what I needed?
Well I found a few more pictures on the HD:
Here is a 12a housing that has been ported. The exhaust sleeve has been retained and the top of the port is right at the inside top of the sleeve:
Hope that helps a little bit.
Here you can see a stock 12a port compared to a bridgeport:
And the same port but with a housing:
Notice how the eyebrow goes into the housing area. Depending on how deep it goes, you will lay your porting bit at a 45* angle and cut into the housing the length of the port + 1/4 inch. You do not want to go into the water seal groove (unless you want to) but do make sure you leave at least 1.5mm of housing between the groove and notch. If you accidentally break through it, you can remedy it with a side seal that has been cut to fit. Lay it down inside the coolant seal groove and grind it until it is flush with the housing. You will be cutting about 1/2 of the coolant seal length wise off. Of course this will not act like a brand new coolant seal wall, but it will help tons in the structural integrity of it.
This is the template laid across the housing. You can see how far into the housing it goes. Some bridges do not go past the water seal, this one does.
6 port bridge:
Here is a 12a housing that has been ported. The exhaust sleeve has been retained and the top of the port is right at the inside top of the sleeve:
Hope that helps a little bit.
Here you can see a stock 12a port compared to a bridgeport:
And the same port but with a housing:
Notice how the eyebrow goes into the housing area. Depending on how deep it goes, you will lay your porting bit at a 45* angle and cut into the housing the length of the port + 1/4 inch. You do not want to go into the water seal groove (unless you want to) but do make sure you leave at least 1.5mm of housing between the groove and notch. If you accidentally break through it, you can remedy it with a side seal that has been cut to fit. Lay it down inside the coolant seal groove and grind it until it is flush with the housing. You will be cutting about 1/2 of the coolant seal length wise off. Of course this will not act like a brand new coolant seal wall, but it will help tons in the structural integrity of it.
This is the template laid across the housing. You can see how far into the housing it goes. Some bridges do not go past the water seal, this one does.
6 port bridge:
As far as the Mazda comp book goes, yes that is true, for competition.
Then again, I have seen bridgeports with small carbs and restrictive exhausts put out over 170whp.
Racing beat does make some good exhausts. If I had the money I would spring for their stainless steel 3" muffler (not in the website, you have to call and ask, $500ish). In general if you have a good road race header and long primaries/SDJ header/RotaryShack MaxPower header and good 2.5-3" high flow exhaust you will be good.
Best part about the bridgeport template, is you can use just the main port as a smallish Streetport. If you don't like it, break her back open and put the eyebrow on it. You can call mazda and get a soft seal kit for about $120, or less if you know the guys ;-). Replace the coolant seals and you should be dandy.
Using a bridge's main port for a streetport is a great way to see if you like the streetabiliy and power of it. A standard streetport will go into the corner seal land area about 40% max, some have even gone 60%, but I begin to fear the side seals at that point. The bridge ports generally do not go into the corner seal area, and again some people have gone a little into it. I would worry about a thin bridge cracking from heat cycling and boost. I will see if I can find the picture of a cracked bridgeport I have somewhere stashed away.
Then again, I have seen bridgeports with small carbs and restrictive exhausts put out over 170whp.
Racing beat does make some good exhausts. If I had the money I would spring for their stainless steel 3" muffler (not in the website, you have to call and ask, $500ish). In general if you have a good road race header and long primaries/SDJ header/RotaryShack MaxPower header and good 2.5-3" high flow exhaust you will be good.
Best part about the bridgeport template, is you can use just the main port as a smallish Streetport. If you don't like it, break her back open and put the eyebrow on it. You can call mazda and get a soft seal kit for about $120, or less if you know the guys ;-). Replace the coolant seals and you should be dandy.
Using a bridge's main port for a streetport is a great way to see if you like the streetabiliy and power of it. A standard streetport will go into the corner seal land area about 40% max, some have even gone 60%, but I begin to fear the side seals at that point. The bridge ports generally do not go into the corner seal area, and again some people have gone a little into it. I would worry about a thin bridge cracking from heat cycling and boost. I will see if I can find the picture of a cracked bridgeport I have somewhere stashed away.
I am leaning towards a large streetport....where should I buy my templates??
Thanks!
Jeezus, let me get this right... I had a friend tell me if I wanted to do a streetport, just use the "main" part of his bridgeport template. If I am understanding this right, a full "streetport" template will be larger on the main port....???
I am leaning towards a large streetport....where should I buy my templates??
Thanks!
I am leaning towards a large streetport....where should I buy my templates??
Thanks!
Using the main port of the BP will give you more power than a stockport, plus later on you can bridge if you like
As far as porting templates go, your typical rotary parts suppliers have them. Hell you can even make your own.
Yes that is technically true. I believe a SP to be any porting done only to the main port. Using the main port of a bridge will give you larger ports than a stock port, but most main port of a bridge will not be bigger than a SP. Reasons being that with the SP you can go into the corner seal groove more (width wise) than you can with a bridge. Remember you need the bridge there for your corner seal and side seal to ride up on.
Using the main port of the BP will give you more power than a stockport, plus later on you can bridge if you like
As far as porting templates go, your typical rotary parts suppliers have them. Hell you can even make your own.
Using the main port of the BP will give you more power than a stockport, plus later on you can bridge if you like
As far as porting templates go, your typical rotary parts suppliers have them. Hell you can even make your own.
Also...thats not a bad idea using the BP main port template....if needs change...step up to a bridge!
i wouldn't bother making ur own templates. better to just buy something that's a proven design. they're made to use the dowel pins to locate the port in the right place(timing) on the housing.
Ugh I had a whole page written out and then my computer blue screened me.
Basically you use a timing wheel, don't port lower than the oil groove, leave corner seal area alone.
Basically you use a timing wheel, don't port lower than the oil groove, leave corner seal area alone.
I would think that designing your own porting template would be worthy of its own thread but thats just me, I'm sure there are threads on it already anyway.
I have never done it but I would leave it to people who have experience with timing and know what they are doing and exactly how every curve of the port will affect timing and flow. All others I would advise to just buy a template from pineapple racing, mazdatrix,etc. they are only like what, $30-$100 depending on what you're doing and that's with both intake and exhaust port templates. If you don't know what you're doing then spend the little extra and do it right the first time instead of junking irons. It's just easier that way.
I have never done it but I would leave it to people who have experience with timing and know what they are doing and exactly how every curve of the port will affect timing and flow. All others I would advise to just buy a template from pineapple racing, mazdatrix,etc. they are only like what, $30-$100 depending on what you're doing and that's with both intake and exhaust port templates. If you don't know what you're doing then spend the little extra and do it right the first time instead of junking irons. It's just easier that way.