Black13B

iTrader: (1)

I did a search and I couldnt find much..

what setup is good for a N/A 13B? what setups does everyone have around here? things to look out for? any help is appreciated.

thanks!

Capn' Wankel

I second this post.....I was just about to post something because I will be looking for an exhaust for my 88 GTU N/A as well.

Is a collected system so much more restrictive than a true dual setup that it would be worth the extra money to go dual? I am only using my car on the street and sometimes to autocross events.....but nothing really serious. Would I free up around what...5 hp more with a true dual? Or would it be something more along the lines of 20 hp?

I hear from previous debates that collected to single catback frees up more hp than running a collected dual setup... Is this true?

I also remember reading that equal length exhaust header is the way to go and that it should start bending no less than 3 inches from the block to run to ur catback. Does this sound right?

And finally, what ways are there to quiet a system down and which are the most free flowing? I am in Florida where there are no emissions laws so I need not worry bout that. I would just go straight pipe back but that is way too loud. Are catalytic converters more restrictive than presilencers? What is the difference between a muffler and a presilencer? This is my daily driver and I dont mind noise but I dont want the people in the car next to me cringing and covering their ears either...

Sorry this is such a long post but I am sure that all of you have been in my situation before. Any advice at all would be greatly appreciated. Thanx guys.

cluosborne

Well, if you have to maintain emissions compliance (such as in New York or California), then a cat back exhaust (I have a Racing Beat cat back on my 88 GTU that I did a write-up for) and Bonez superflo cat would be best all-round.

Otherwise, Mazdatrix offers a racing exhaust that claims an increase of about 20 whp.

Black13B

iTrader: (1)

20 whp?

what type of setup is it? do you know off hand?

Rotorific

iTrader: (1)

Hey capn good job on the GTU haha

well there are plenty of combos ranging from racepipes that replace the cats to full headers that come in true dual format and street format...the true dual format is the way to go for all out power...the racepipes are a good buy if you dont want a header....from there you can either go single exit or dual exit...I personally have a single exit i love it... There are plenty of mufflers out to choose from...most people on this forum will either tell you racingbeat, apexi, greddy, or corksport... The maximum diameter tubing is 2.5 for an NA and if you use dual mufflers the maximum for the y pipe is 2.25 this is recommended by Rob from pineapple racing i personally use 2.5 from manifold to my muffler and presilencers are a good choice if you want your car to sound like a rotary and not a honda...they are not restrictive...thats all i have to say about that...-Gabe

cluosborne

It's a racing setup. www.mazdatrix.com Look under their Racing section.

Offhand, I don't know much else about the setup other than it's loud (there's a video you can view to give you an idea of how loud).

zelgadiss-san

I'm planning on replacing my stock exhaust some time in the not-too-distant future, and I'm gonna go with the Mazdatrix true duals with RB mufflers. the page says (and shows in a dyno) that they got up to a 28% increase in RWHP.

Capn' Wankel

TY for the info rotorific.....do I HAVE to have a muffler though? Or would it be quiet enough to just run presilencers?

TonyTurboII

Good exhaust?

Either way be prepared to spend some money.

Loud and illegal - Mazdatrix
$1,235.00+

Heres the link. Your choice of mufflers.

Quiter and legal - Racing beat
Catback - $576.00
It appears their header is no longer available. You might want to call and check.

BadBoy

noone likes the GREDDY POWER EXTEME?

Fred

Phu5ion

i didn't see it either on RB's site but it is still up there, with a little looking i found their collected header .

http://www.racingbeat.com/resultset....rtNumber=16130

DJChunter

i got a RB header into 2.5in pipe then into a dyno max bullet race muffler.. the system is loud but i notice a big increase in power.. and good for massive flames.. oh ya this is a single exit too.. Dave

wpgrexx

you guys have to decide what you want in an exhaust. all out power with no worries of cash or laws, or do you want quiet oem replacement. there are many options, cheap pacesetter from j.c whitney is like under 500 for hedder and complete exhaust, but it won't last long, but you could go with a full race dual exhaust made from ss for a a little over a 1000. i have no worries about emmisions and got the dual exhaust, big power too be gained.

Rotorific

iTrader: (1)

wouldnt recommend the no muffler approach its loud enough that it will attract the wrong kind of attention (cops)

Rotorific

iTrader: (1)

The power extreme is a nice exhaust but i mean i could find better for that price (900 and up) plus it is discontinued

rotarygod

iTrader: (1)

Cap'n Wankel: To answer some of your questions: 3" is the minimum that the pipe should leave the engine before it turns. No aftermarket header currently follows this rule. The reason behind this is that flow bench testing of the rotary exhaust ports shows a decrease in flow and an increase in turbulence within the port itself if there is an abrupt bend immediately after exiting the engine. We want the exhaust to exit as quickly and smoothly as possible. Go look at a formula 1 or indy exhaust header. Actually go look at any race car exhaust. They all go straight for a few inches before turning.

I have had just about every exhaust configuration imaginable so this is my personal experience with them. Others may have different opinions and I respect that. A true dual exhaust system will free up an impressive amount of power on a totally stock engine. Then again so will just adding a header. The problem is within how terrible the factory manifold is. It doesn't really matter how good your cat back is as long as you have the restrictive box manifold still installed. A cat back will free up a few horsepower but nothing that I personally consider significant enough to justify the money spent. A header is the best bang for the buck, even the Pace Setter one although long term reliability is an issue with theirs. I originally installed a pace setter header and was very impressed. I had a 2.5" straight pipe instead of a cat going through 2 straight through Brullen mufflers. Sounded awesome and wonderful power increase over stock. Then I heard about duals and fabbed my own. Cut the pace setter header and just dualed the pipes back to my mufflers. Great increase in low end but top end didn't feel as nice. The sound was horrible. Loud too but I don't mind that. It sounded like a poorly running chainsaw as opposed to the more F-1 like collected sound. Gas mileage went up. Now I run a ported motor and a long primary system. This is my favorite setup. Both pipes collect at the 100" mark into a 2.5" collector that gradually expands to 3" then through a Warlock race muffler. The muffler has a bypass which makes it a straight pipe. I have a Q-tec exhaust butterfly valve on this which lets me run a straight open exhaust when I want it or a quiet system when I don't. 2.5" collected is a good system. 2.25" is too small I don't care who says otherwise. 2.25" is the largest that will benefit after the y-pipe on a 2nd gen but the collected can hit 3" before it gets too large. 3" does not flow too much. Fiqure out the total runner area of a true dual (2-2" pipes) and then compare it to the total area of a 3" pipe. You'll see why. For a streetported motor collected is the only way to go. I tried the dual setup on my streetported motor and lost power over the collected system. This is due to the increased overlap of my engine and the fact that the engine really needs a good scavenging exhaust system which a dual is not. Dual works better on stock timing. You can absolutely not use a dual system on a bridge or peripheral port. I laugh when people say this is the way to go on ported motors since I've done it.

If you have a stock port motor and want great drivability then dual may be the way to go for you. If you have a ported motor then think about a collected system. If you have a stock exhaust now anything will be an improvement.

Once again this is my personal opinion. Others may differ or disagree.

Black13B

iTrader: (1)

i went to mazdatrix, that exhaust system video they show.. it doesnt seem too loud.. doesnt even seem as loud as all those civics cruising around with fart cannons.. thats how it SEEMS anyways..

ive heard straight pipes on a N/A 13B, that was pretty loud at all areas of the tach...

My Junx

I have a 2.5 inch straight pipe from the stock manifold back to what would be the rear-most cat, and then a 3 inch SS cat-back from corksport. It's nice and loud but not obscene. Good flames too Very nice power gain on my seat -of-pants-dyno. But the best part is the price...<300bux. Will be getting a header soon (christmas?)

Oh I forgot, is your car an S4 or S5? S4 will need some decent back pressure to open the 5-6th ports..unless you wire them or something. If it's an S5 you are good to go with a wide open exhaust.

TunedRunner

rotarygod:
What about exhaust inserts for the sleeves. Do you know anyone, or have you used these on an NA? Have you thought about making the straight portion of the header the same shape as the port and then using controlled expansion (i.e. megaphone) to end up with negative pressure by the time the intake is uncovered?

I am gathering knowledge to create my own exhaust and I would like to get the best possible scavenging.

I was thinking of replacing the sleeves, but I really don't want to take my motor apart because I know once I am in there I will want to replace everything and port it. Then it will never be ready by spring (because of funds, not time). I would rather spend my money on mandrel bent tubes and such.

KiyoKix

"2.25" is the largest that will benefit after the y-pipe on a 2nd gen but the collected can hit 3" before it gets too large."

Hey rotarygod...don't you mean 2.25 is the smallest that you can benefit after the y-pipe? If you should I go and get rid of my system and get something even smaller.

Xentrix

I had a power extreme, I sold it because of my driveway. Those cans were maybe 2 inches off the ground.

I've posted this clip a million times by now exhaust test (right click save as). That compares the volume of an na with headers and a presilencer with 3 different catbacks, it starts with a stock catback, then power extreme, then the corksport.

From my experience with all 3, the biggest gain is with the header and presilencer/midpipe. The car is much much better than stock. With the stock catback the car still had low end torque. With the PE there was less low end but more top. With the CS much more top end and alot less low end.

Here's a vid of how loud NA's are.

110db.

http://zeffy.novus-logic.com/media/fc%20loud.wmv

rotarygod

iTrader: (1)

TunedRunner: Who do you think has the new sleeves in his engines? !!! My 2nd gen turbo uses the new machined sleeves and my GSL-SE uses stock sleeves with inserts. You figured out exctly how I did my system. The inserts still require that the header pipes be a little oval shaped just not as much as the machined sleeves. My 2 header pipes are 2" and collect into the base of a megaphone which is basically a 2 1/2 inch pipe that expands to 3". This is the best setup I have ever tried and is better than any aftermarket setup I have ever used. If you are running a 2nd gen n/a good luck on using inserts. Can't do it.

KiyoKix: I was referring to the collected part being too small if it is 2 1/4". After the y-pipe it doesn't matter. You could split it to 3" and not lose any power. My 2nd gen runs a 3" pipe which splits to two 2 1/4" pipes but then again it is a turbo. There is actually a benefit to using a larger area after the split which many advocates of a single exhaust never think about. If your y-pipe splits into pipes that combined have a greater area than the collected pipe it actually gives you a little benefit in tuning in that it is sort of like using a megaphone. The expansion in area broadens the power band a little (not much though). Many people debate this. This is better suited for n/a cars running headers since a turbo would work best with no exhaust. I prefer to just run 100" long primaries then collect through a 3" muffler but then again it is also on a 1st gen.

Capn' Wankel

Back to the idea about starting the bend in a header at least 3 inches from the block.....

Do you think that it is a possible and beneficial idea to fab a 3" spacer or flanged spacer to bolt on to the exhaust port and then just simply bolt on your header to that in order to get that 3" run that is stated as being aerodynamically beneficial to the flow of the exhaust port??

I am thinking about getting the true dual header from racing beat or somewhere and fab this 3" spacer and run a presilencer and one mufler on each 2.5" runner all the way back. The runners and whole deal will be custom installed here in Tampa out of Stainless Steel tubing for relatively cheap labor costs. Is this a durable material to be using for the exhaust?

Does this sound like the way to go for an 88 N/A with stock porting retained, 5th/6th ports operating, daily driven SPIRITEDLY, with quite a bit of noise toleration but a shallow pocket for noise tickets? Will this 3" long flange idea be beneficial do you think? Do 2.5" runners on a true dual setup sound right or would I benefit from 3" tubing all the way back and an electric port activation system? Are there really any differences between mufflers or presilencers quality wise and flow wise?

With these answers I will be able to order the parts and get this stuff on real soon......Thank you guys sooooo much for all the time spent on helping me wth these decisions!!!

FPrep2ndGenRX7

http://www.sdjmotorsports.com/Headers.htm

They sell what you want. Kinda pricey thou.

rotarygod

iTrader: (1)

They have probably the best designed aftermarket setup that I've seen yet. They look pretty good. Looks like a collecteor that expands to 3" and they stay fairly straight out of the engine.

I suppose you could put a spacer in there. Please understand that my basis for the 3" rule is based on airflow numbers and not dyno numbers. More specifically they are based on Paul Yaw's flow bench numbers as I can't take credit for his work. Logically if there is less turbulence out of the engine then it can flow more air and hence make more power.

For a stock port rotary you will find an impressive amount of horsepower freed up. I truly believe the 30 hp number Mazdatrix claims to be true. Just curious as to why you are going to go 2.5"? Are you going to have it slowly flare to this size? That may be beneficial.

As far as presilencers vs. mufflers goes a presilencer is a muffler. It is a front muffler but smaller. There are differnt internal styles available and some work better than others. the kind that Racing Beat sells are very good units but very pricey and heavy. The other type has little bumps inside which protrude into the airstream. These bumps are actually little holes which bleed off some air and send it into the fiberglass (or whatever) packing. These are terrible for airflow and very restricitve. Turning them around backwards actually makes them flow a little better but they are still too restrictive for any real performance system. I actually have 2 of these lying aroung that spiders are making a home in. It is really funny that this is the exact same design as many of the big aftermarket import mufflers that are so popular. I looked inside a few and laughed that these guys think they will get power out of them. Even worse there are inserts which further decrease area and induce turbulence. The only reason that some people claim no horsepower loss when the insert is in place is due to the fact that their mufflers flow like crap anyways.

Sorry I got off on a tangent but I hope I answered the question.