ok i been thinking of porting my engine doing a pineapple street port but bridging the 5 and 6th ports but aslo having them work with the 6 port actcuators with the pineapple sleeves.

the question is has someone done this before?which i think someone had done this before which i would like to know how did it performed?

like horsepower and torque rpms and numbers.

i would like feedback from the people here thats all.

 

Forgive me for not being diplomatic here. I'm not attacking you so don't take it that way. Please I beg of you, do not fall into that crap porting style trap. NO ONE has EVER made them work even slightly satisfactorily in the least in naturally aspirated form and no one ever will. Auxiliary bridgeports are an absolute waste of effort 100% of the time. I still can't figure out why the idea still gets passed around here. There must be a short yellow bus somewhere that I can't see with a flood of people getting off of it. Some claim to have made these ports work but from what I've seen their work has been terrible and their cars craptastic at best. Keep in mind that is the standard in the RX-7 community in general. I'm sure that'll offend some people but the truth isn't always friendly and I'm not subtle. There are the random few who have spectacular vehicles though.

Keep it simple. Do a streetport. Nothing more aggressive. You won't get anything more out of it on the street. I suspect this will still be a street driven car. Get rid of the notion of bridgeport or peripheral port anything being street driven. "Streetable" does not mean "can physically be driven down the street" although that's what many people here will tell themselves in order to justify the hassle of putting up with them and their near single digit gas mileage numbers. Those ports aren't streetable. I don't care how many owners of them come on here and tell me otherwise. I'll respect their opinions but they're wrong! Simple as that. I won't compromise like that just to say I have a port I can't fully take advantage of anyways. Keep the auxiliary ports working too. Don't lose power on the low end at the expense of that 1-2 on the top end that you won't feel anyways. You can't feel anything less than a 10% gain in power. Your mind may disagree though.

Here in order are the biggest gains for the money.
1: A true header, and a full exhaust. Stick to a 2-1/2" after the collector. No point in going larger.
2: Aluminum flywheel
3: Street Porting

Everything else is minor after that. Intakes do a little bit. Ignition boxes do a little bit. They do add up though. An ecu can do quite a bit for you but I'd save it for last. Even then if you do get to that point and decide to do an aftermarket ecu, only use one that completely eliminates the factory air flow meter. Some people claim that the factory afm is not a restriction since it doesn't open all the way. Again, I respect their opinions but they're wrong! Then again I've actually flow tested them on a flowbench so what do I know? I have heard uneducated excuses that say flowbenches aren't useful but the ignorant often make excuses for everything. When they run out of them, they just pass on the insults. You can tell by now I'm sick of alot of the bad advice that goes around. Don't listen to ANYONE that would suggest an Apexi S-AFC. It's crap. It stands for Stupid Air Fuel Computer and that's what it is. Why spend the money on it when that money could have been put towards something that actually did it's job well?

Don't over complicate things. A streetport is more than capable of hitting 200 rwhp on a STOCK intake manifold if EVERYTHING else is done properly. We have never once seen an auxiliary bridgeported engine hit that number. Flow is so terrible through those ports anyways that the bridge can't really do anything other than roughen your idle.

Don't take any of this as criticism. I'm not doing that to you. I'm trying to stop you from making the same mistakes that get made over and over and over again yet no one ever learns. They all magically think that they somehow are smarter than everyone else who has ever tried it and failed. Or they mentally convince themselves that a bridgeport is in fact better and therefore their car must be better for it with no frame of reference to verify it. This is what usually happens. You get people that do it and already had themselves convinced beforehand that it was better because it was a bridge. These people are delusional and slower than they should be. Don't fall into this trap. Don't overthink things. Keep it simple as you'll ultimately be faster and will have spent less money in the end.

If this is a race car and you have a 4 port engine, then we can discuss bridgeports and how to get power out of them. That's different. Streets for the street. If you have a turbo and want a bridgeport on the street, that too is doable. It doesn't sound like that's what you are doing though.

 

^ Nice comments. I agree with everything you said except that if you know what you are doing you can make great power with a full bridged 6 port. Way more than a streetport.

 

im not trying to go against your opinion i fully understand what you are saying, but because i said the 5 and 6 port bridge and having them to work also with the 6ports sleeves working too, so when they are closed i have street port idle but when it opens at 4k rpms it be the bridge 5&6 ports working and having a greater horse power reading, thats what i think.

its a idea.

think what the honda v-tec engine(i know i cant compare a pistion engine to a rotary engine)
it has extra lobes for more top end for the power in example: the non- vtec lobe is like a 238 deg but then the vtec lobe is 268 deg and it opens at a certain rpm like 5100rpm., it just an example.

 

You aren't the first person to think of that though. It's been done. Many others have had the aux ports bridged and kept working sleeves. It just doesn't work. It never has. The idea sounds good in theory but in practice it isn't all that great.

The problem has to do with flow. This is one area that flow and not velocity is in fact what matters. Here's why. A bridgeport opens earlier. There is no intake velocity at this point. It is relying on flow to help get more air into the engine sooner. As the port opens and the rotor starts pulling air in, it starts here. The port is so small that it isn't doing much. On top of that the auxiliary port sleeves run through the airstream. This adds tons of turbulence to the airflow which means that what the small bridgeport may be physically capable of flowing on it's own, it's still not going to since the added turbulence is going to keep it from being as efficient as it could be. All you are basically getting is nothing more than a small vacuum leak (forgive me for using such a crude if slightly inaccurate term). You aren't effectively going to get anymore airflow to the engine. If your exhaust isn't flowing real efficiently, you'll do nothing more than send extra exhaust gasses back to the intake killing your power.

It's never worked well. Many others have tried the exact same thing you are proposing. It's not a new idea. You'd be surprised what people have thought of. We've seen everything from mild porting to an invention called "cheese ports" which failed miserably. The way the auxiliary ports work is basically the rotary equivalent of vtec now except Mazda first used it in Japan on a 12A back on 1981. It is variable timing. You are going to do better with a streetport. I know you might not think so and may still be tempted to do it but I'm just telling you, it hasn't worked well in the past and there is 0 reason to think it'll work now. It just doesn't.

 

If you are using a custom intake manifold, carb or ecu, full proper exhaust, ect, I'd agree with you. If this is a stock intake manifold, exhaust manifold, etc, I'll disagree all day everyday.

 

thank man for your feedback i think ill just do a streetport then , i was just doing the reserch and i see what you mean.thanks for not being like the others on here

 

My 2 cents.

1st, a little history of my rx7's
My 1st RX7 ('89 gtu), I wanted to learn about rebuilding, so I tore the motor down, but because I was so new to it all, I had it put back together by a local rebuilder, he mildly street ported it too, which I wanted too see but didn't get too.
Anyway that RX7 turned into my daily driver.
My 2nd RX7 ('87 gxl), basically same thing, but this time I did the rebuild totally myself.
It runs but I haven't got the engine broken in yet, (lazy).

On Aux bridge porting.
I too wanted to do this, but I went without it.
Because of many reasons, 1 of which is because all these threads and posts about it.
Basically they either are wondering about it or saying its not good.
There were no threads or posts that claimed this idea works with evidence.
Another reason is, when I rebuilt my 2nd motor, I went with another porting idea.
I still like the Aux BP idea, and still want to experience it.

On 5th and 6th port sleeves an actuators.
I have had bad experience with these things. They can get stuck. I believe they are an air restriction. IMO get rid of them.
On my 1st RX7, a little more than a half year ago, I did an emissions removal.
I took the 5th & 6th port sleeves and actuating rods out and blocked off the holes. I also wired the VDI open.
I noticed while driving that I didn't have a hesitation around 3500-4000rpms, and I have smooth power all the way up.
btw, I get 19-22 mpg with this rx7.
I have a friend, that did an emissions removal on a stock '88 n/a rx7 that he use to own, he wired the 5th & 6th ports open, also removed the sec. throttle plates.
And he noticed better performance too.

On drive-ability, or "streetable".
I did notice with my 1st RX7 after the emission's removal, that I had some low end issues like bucking etc. I daily drive this thing, I'm use to it, most of the time it drives fine in the low end. I can only imagine how it could be worse with bigger porting.

Its good that ppl warn others that "it wont be streetable" when talking about such things.
It also seems to me that they talk about it like its the worst thing ever.
I have heard of some ppl who drive "unstreetable" engines, and they are ok with it.
I believe that there are "car guys" out there that believe in "throwing a car around", meaning that there not driving "nice an easy", or "smooth an steady".
Instead there getting on the gas, throwing it into the corners, etc.
I believe that most (rotary owners) are "car guys", and bet that at least half of them are that kind.

So it depends on the driver. If there is someone thats talking about porting and street-ability, Im sure they know that there might be an issue with street-ability, and that they wont mind adjusting to the difference.

On porting N/A's.
Us N/A guys think about porting because its the one key to more power besides the usual mods like performance exhaust system, air intake, light weight components, etc.

Some have said that the only porting that can be useful / good for an N/A, is street porting.
The thing is, on an N/A engine, thats not much.
So we tend to go to some extreme style of porting like, bridge, peripheral, siamese secondarys .
And for some reason we wonder if it will work well, so we make threads and posts about it, only to be bashed upon, and not find much proof that these style of ports work well.
So why don't we (us extreme n/a port wonderer's) just do it, an experience it, an see how it turns out.

I did it (a semi extreme style of port) with my 2nd RX7, and so far its good, theres no low end problems, and it drives well.
I just need to get the engine broken in and start taking the rpms up an experience what this engine can do.


That is all.

 

^^not to bash so u removed the 5th and 6th ports and wired the vdi open on one of your cars???and u didnt notice any drop in performance?? i also did the to my 1990 gtu and let me tell u that thing lost all its ***** in the low end and i told my self that it didnt matter anyways because i would be above 4k rpms all the time anyways.well that dosent happen and i hardly ever got to 4k when i was on the interstate.

removal of these things in a 6 port n/a shouldnt be done,u gain maybey 2 hp on the top end by removing the sleeves but u lose 15hp on the bottom end where u need it more. these cars are gutless in my opinion to begin with no one needs to make that worse.

and the guy that was stating his opinion wasnt totally ruling out a n/a bridgeport on the street , he was more or less saying that it cant be dont with the stock tb stock ecu and stock intakes.. the t2 intakes are lacking when flowing the bridgeports so a n/a intake is horible.

 

There is a time and a place for a bridgeport. A street driven vehicle isn't the place for it. It's as simple as that. My problem with the use of the term "streetable" is that many people try to justify driving their cars on the street by really broadening their definition of the term "streetable". Some would have you think that it means "can physically be driven down the street". That's not good enough. A Cessna airplane will physically drive down a street. An F1 car can physically drive down the street. A Top Fuel Dragster can physically drive down a street. None of these is "streetable". If you skew your interpretation of the word far enough, you can justify anything and more people do this.

Here's a fact and many people have a hard time believing it. If you take an engine and bridgeport it but you keep the stock intake manifold, stock exhaust system on it, stock ecu, etc, it will make LESS power than stock! Street use is a compromise which means certain things need to be designed around it. Bridgeports don't like compromise and don't work well with it. The best and fastest street engine is the one that has the widest powerband with the greatest average power. It's the one that is smoothest to drive, has the least compromise in terms of gas mileage and could theoretically pass an emissions test if fitting with emissions control devices. Peak power means almost NOTHING on the street if the rest of the powerband suffers.

 

I think the main problem is that alot of people are not trying new things because of the discouraging comments that is on this site. Truth is that most people on this site will tell you something that they heard dont work and make it seem like they know, it doesn't mean that they're right. The 13b is capable of alot hp in NA form so you should try any idea that make sense.

 

I'de listen to rotarygod rather than rotormind! My 2 cents

 

let me hit you with some knowlege...

now that i've said that famous line, i am one of those jackasses who drives a bridgeport every day.

i've got the good old 6port bridgport with weber downdraft carbs and 2 1/2inch headers and exhaust.

the good:
- engine acts exactly the way i wanted an engine to act when i'm driving. i cant even describe it properly. the car is amazing with that engine setup.
- sounds badass
- rarely shoots flames (some people love flames though)

the bad:
- fuel milage is amazingly horrible, but thats partly due to the carbs.
- police tend to take notice when they see a miata with, what sounds like, a v8 with huge cams

by no means am i an expert, but i've been living with the car for a couple months and i've been loving every second of it.
i'm also up on the maintenance, so i'd be happy if it lasts a while before i need a rebuild.

 

Thats just my 2 cents. I just telling the guy if he want to do something then do it. The ones that knows best are the ones that actually try, besides I know people that are doing it and getting good results from it and theres no bad results if the accuators are working properly.

 

I will respectfully disagree with that. Here's why. There are people that try things without having ever tried anything else so they have NO frame of reference. This happens WAY too often here and then others encourage them to make the same mistakes over and over again with nothing to compare it to but stock. Just because you can do better than stock doesn't mean much as an exhaust alone can net you damn near 30 hp. Porting is actually the LAST mod anyone should do anyways.

Having no bad results if the actuators are working properly is irrelevant as there are no positive benefits either.

Here's what I'll need to see from these experts in order to believe it has merit. They ALL had better have EASILY topped 200 rwhp as you can top 200 rwhp with mild streetports. You can top 180 rwhp with stock ports and it's been done. I have yet to see any of them top this number. If it worked the way it should, they should be in the 210-215 rwhp range. Too bad no one is.

Streetport it, get it tuned properly, do everything else properly such as good intake, exhaust, nice flywheel etc, and enjoy your 200 rwhp engine all day while others with more extreme ideas scratch their heads wondering why they can't match it.

 

Im not telling the guy that his first mod should be the 5th and 6th bridge port. but if my motor was open and I wanted to go that route, then why not give it a shot. One day someone is gonna come on here and prove that it works and he wont have to open back up his motor to get it done. I do think that he is going about it the wrong way but if he is streetporting the motor, and leaving the accuators in, then he'll be fine rather its making huge difference or not.

 

Rotarygod, you said that the Apexi safc is not worth the money for what it does...and I agree!!
But though many doesnt have the money to go a full stand alone, do you think a Rtek7 ecu will be benificial for its price?

Bridgeporting on a car that will be driven everyday (for me anyways) seems too irrational. Some people can get used to it but, since people are different, there is a norm for the term drivability. And it seems that the problem is Idle, and the fuel mileage.
I already am paying about $68 for a full tank, and going bridge port will just waste my budget on something that I will not be doing full blown (IE: Full intake setup, fuel setup, and exhaust setup).

A mild to serious streetport is a good enough setup for the normal people. As Rotarygod said, you can get atleast 200rwhp from it. A full bridge port will net you atleast 250-275hp, but is it really worth it for all that drivability trouble for a street driven car.

I was thinking about doing a mild streeport on an engine im about to rebuild. I also wanted to keep my true dual exhaust setup, though I read that collected is a way better solution for ported engines because of overlaps? I mean how much power increase in the rev band would a collected system make over a dual exhaust setup?

 

i love this thread. its a pissing contest based on streetability opinions.
as black knight rx7 fc3s mentioned everyones different, and how will you know until you try?
i'm absolutely pleased with my bridgeported engine. it idles funny, gets shitty gas milage, and i think thats why i love it. it makes power and has a ton of character. when it all comes down to it, its all about about how the driver feels about the car.

 

Since people seem to dislike the 6-port with a brigde, is a 4-port bridgy better for N/A purposes?

Assuming all supporting mods are installed, which engine will be better to do a bridge port on? Which one will produce better power?

BTW - for conversation sake, this will be a weekend car. It does not need to be 'streetable' but will be driven on the street to and from the track.

 

i think 4 port might be better. [postulation/]

the factory PP housings have an intake closing of 75abdc, the factory 6 port engines close at 70abdc. the RB bridge closes at 72abdc.

theres just no need to have them open later than they already are.

the advantage of the bp, aside from more flow; if its done right, is that the intake OPENS earlier.

 

That's called "tolerance". You are tolerant as you admit all of it's faults on the street. It's not "streetable". Those 2 terms should not get mixed up. You do not drive a streetable vehicle. You drive an unstreetable one and are tolerant enough of it to put up with it on the street. A person could physically drive an F1 car to work on the street(assuming of course you ignore all the laws that prohibit you from doing so). The car isn't streetable. See how that works?

I hate the generic argument about not knowing until you try it. That sometimes works but it has to be kept in a proper context. In other instances there is knowing without trying which means someone doesn't do something because they know better. I know better! There's a reason I don't so certain things. It's because I'm realistic about what I want and I know what I'll tolerate. I won't tolerate unstreetable on the street. You will and that's OK. It has now been stated that this is a weekend car and not a daily driver. That changes things a bit because typically people with put up with alot more when they don't have to drive it everyday. Play cars are fair game when it comes to mods.

Too often we see people ask questions who don't know. These people more often than not only know they want to go faster. They are also under the assumption that if a streetport is good, a bridge must be better and therefore they should bridge it. These same people usually don't know better and aren't aware what they downsides are. It's better to educate them on what works, how it works, and why rather than to tell them to just blindly "go for it". How do you know you won't die jumping off of a cliff unless you try it? Go for it! That would be really stupid advice. If after doing all of their homework, they determine that they are willing to put up with the downsides to a more extreme porting style, so be it. I just think it's nice to let them know what to expect first. With a bridge they can expect to be very tolerant of the way it drives on the street. You have to be to drive an unstreetable setup everyday. It's not a pissing contest. It's an educational experience. There is an aspect of fun that is obviously factored into all of this and I do know that bridge and peripheral ports can be damn fun! Unfortunately for me the fun wears off when you watch the gas gauge go down and realize you only got 200 miles on $60 of gas.

 

i see where your coming from and i can agree for the most part.
i guess not everyone likes to jump in dick first on a daily driver like i do.