0verb00st

Before I say anything, I did search...but the answers where vague at best...My first question is how much back pressure do the 5th and 6th ports need to open by themselves (no modification needed). If I just get a catback exhaust, will the ports still open? What if I get a new header? Is it only when I start gutting the cats that the ports stop opening? My second question is what are my options for exhausts...most of the threads on this forum are biased towards racing beat...I looked on corksport and mazdatrix and they dont have much of a selection either. Does anyone have any experience with any custom setups (personally I want a single drivers side catback apexi n'1 exhaust). I started this to get answers to my questions, and hopefully yield a thread that collectively answers all exhaust questions in a single thread. Thanks in advance

The Shaolin

iTrader: (5)

2some psi

maybe, maybe later in the RPM band...try it. should be okay, depending on size.

no.

just do the air pump conversion and be done with it.

phoenix7

don't you think we're biased for a reason???? Maybe I shouldn't mention all the free parts we get for mentioning RB in every exhaust thread. wink wink RB, hook me up!

Do you have an S4 or S5??

The S4 uses exhaust pressure to open the 5th/6th ports
The S5 uses pressure from the air pump to open the aux ports

If you go with HUGE pipes in your S4 then you will not be able to open the 5th and 6th ports.

Try an RB header and midpipe with any catback you want and you should be fine but deaf.

Racing Beat for the Win.


and this topic has been beaten to death and i don't believe you searched long enough because I KNOW your questions have been answered in the past.

TheDarkRacer

^^ the questions might have been answered but you might have to read though 10 threads to find half the answer... Im a lurker and search everything, but most of the exhaust threads dont contain the detailed specs about the aux ports.

phoenix7

well I'm a detail, numerical data junkie but when it comes to the 5th and 6th there are only two answers:

S4 depends on exhaust pressure
S5 uses the air pump

How much pressure is needed? MAzda designed it to open at around 5K RPMS using stock exhaust piping but I apologize for not knowing the exact amount of airflow required.

His options? Open to his little heart's desire.

I recommended RB header, midpipe and nay catback he wants ( but he'll need earplugs to stop the bleeding.)

ericgrau

iTrader: (1)

RB has a fairly quiet catback too, or is that not enough once the cat is gone?

alexdimen

iTrader: (13)

RB also has a mid pipe that allows operation of the 5/6 ports. Try the setup you want. If the ports still open too late, then you can put a restrictor plate in the exhaust right behind the cat.

wiL87

so that extra kick in power at around 5.5k RPM is the 5th and 6th ports? i read some where that it wasn't and it was just the "happy RPM" ...ehh

Shainiac

iTrader: (7)

What???? A noticeable bump in power around 5k would be VDI for those guys with S5 intakes. The 5th/6th Ports open at 3800ish RPM. Please stop beating this topic into the ground.

staticguitar313

iTrader: (2)

Borla Catback Full Stainless

rotary revolution 7

RB road race exhaust is the **** try it out if you have the money

Sideways7

iTrader: (7)

Yes, that is basically correct.
And to answer the OP's question, any change in the exhaust AT ALL will change where the aux ports open. They may still open with a new catback, but they will open later than they should, which hurts the powerband. Also, anything that replaces the stock cat (midpipe, header, etc.) will cause it not to operate as stock since it gets the "backpressure" from the stock cat. The only system I have seen that reliably opens the aux ports as stock is the RB header/downpipe with the RB presilencer.
For catbacks, there are 3 common catbacks that people get: racing beat, apex n1, and corksport. The RB is a dual exhaust and is relatively subdued, while the corksport and N1 are singles and can be pretty damn loud. It is all up to personal preference. I have the RB header/presilencer and apex N1 and love it, but it does get annoying at times.
Also, there is no such thing as a drivers exit N1, it always exits on the pass side. What you want is the Apex GT exhaust, it exits on the drivers side.
You can actually find some clips of these exhausts on www.globalvicinity.com.

RodRx

Okay. I know to some people this 5th and 6th port thing is an annoying question but to the members in here that are new it is extremely useful info. THe search feature pulls up so many topics that you would have to spend hours to read all of them. My problem with the 5th and 6th port is that my new ride doesn't have the actuators or anything. People keep telling me that I would be happier if I was to put them back on as far as low end power goes. Why? My N/A S4 seems to run fine but it is hard to tell the difference when I don't know what one should run like. What are the advantages or disadvantages?

Sideways7

iTrader: (7)

Yes, I know how it is trying ot find info on stuff like this, which is why I try to help out.
The point of the aux ports (officially the 6PI system) is that when they open at high RPM to give more air when it is needed, but stay closed at low RPM to maintain good air velocity, which is needed for low rpm power. It works the same way as Vtec, except this came first

The advantages of it working properly over wiring the ports open like you have is that you get better low end power and better gas mileage. There are no disadvantages at all.

0verb00st

so what setup would yield the biggest increase in power throughout the power band?

RodRx

I appreciate the straightforward answer. I knew that the 7 had a rep for bad gas mileage before I bought mine. I just didn't want it tohurt the engine. Thanks.

0verb00st

http://rx7.com/store/rx7/fcexhaust.html

I found this...might answer some questions and looks like a reputable dealer...does anyone have any experience with them?

Fc3s_d1jp

Yea i got the Greddy Power Extreme Catback from them, I am very pleased galvanized piping stainless steel mufflers.

My5ABaby

iTrader: (7)

1.8 psi.

REHarrison

I thought that only S5 13b's had a 5th and 6th port? and the S5 TII and all S4's were four ports?

My5ABaby

iTrader: (7)

You thought wrong.

K!NCH

iTrader: (2)

Stock exhaust, oh yeah 8).
When I get the money I'm goin with the Apexi GT Spec catback.

phoenix7

nope. TII's are 4 ports. The NA's are all 6 ports derived from the supercharger setup MAzda was playing with when making engine prototypes.

you want an awesome exhaust for the NA then use the RB true duals. Specifically designed for maximum HP and it's streetable due to it's low noise/deep tone at low RPMS. Once you get on it WOT you get to hear the BRAAAAAAAAAAAAAAAAAAAAAAAAAAP of the rotary. It's like sex for your ears.

wiL87

but with the RB FULL exhaust systems, aren't you not gonna pass smog (because the presilencer replaces the cats)? That's the reason rx7.com has the bonez high flow cat right?

Drivarotor

Yes I do. I bought the RB collected header, Bonez cat, and Rotary Performance cat back. I chose the RP catback due to it's "near-stock appearance". I am trying to keep my S5 a sleeper. The catback is louder than most, but definitely is not obnoxious. It also gives the "Braaaaaaaaappp" under load, but there is droning when in 5th gear at highway speeds (60-75 mph). Aside from that, I absolutely LOVE this setup.