General Exhaust Info/Questions
#26
100% Italian
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changing the exhaust shouldn't cause any problems. I know I'm gonna change mine. I'm in ca and I do have to worry but mainly just about cops if my exhaust is too loud.
#27
RX-7 Guru
First off, there are a few components to the exhaust. There's the catalytic converter, or cat, that's closest to the engine. Then, there's the "cat-back" section, which is literally from the cat back to the tailpipe.
Legally, you can change out the cat-back section of the exhaust. By law, you can't do anything with the cat, but in many states it's kind of a grey area - it's illegal, but so is taping movies off HBO. No one really checks up on it.
There's also the exhaust manifold - this is a cast iron hunk bolted right to the engine, and the cat is bolted to it.
When designing the exhaust system, Mazda (as most car manufacturers do) had a number of objectives -
- It had to be quiet.
- It had to not rust out before the warranty expires
- It had to be relatively inexpensive
- It has to pass VERY strict federal emissions standards
- It has to be easy to install on the assembly line
ALL THOSE factors are looked at BEFORE performance.
With that said, Mazda has traditionally made VERY restrictive mufflers on the RX-7's. Rotaries are VERY loud, and as I'm sure you know your car is VERY quiet. The only way to accomplish this is with a massive, restrictive muffler.
The cat does quite a bit of sound muffling as well. Even if you had no cat-back on the car at all or just straight pipe, the car wouldn't be THAT loud. It would be loud, though
.
Aftermarket exhausts typically are better built and of higher quality components than stock, and one of their first objectives is making more power. They will be louder than stock, but with just a cat-back, a good exhaust will have a nice, deep, sporty sound, but not loud and obnoxious.
Aftermarket parts to replace the cat are typically called midpipes or straight pipes. Again, grey area, and you can't pass an emissions test with one, but power can be gained there.
The stock exhaust manifold is replaced with headers, which typically is a tubular manifold that keeps the exhaust pulses separate for more power. Many headers are legal - they bolt to the engine, and the cat bolts to the headers.
Right now, there isn't much out there exhaust-wise. In a year, you're gonna see TONS of options - rotary powered vehicles have always attracted enthusiasts, and enthusiasts like modifying cars.
Changing the exhaust should not lead to any reliability problems - just more power and a better sound.
Dale
Legally, you can change out the cat-back section of the exhaust. By law, you can't do anything with the cat, but in many states it's kind of a grey area - it's illegal, but so is taping movies off HBO. No one really checks up on it.
There's also the exhaust manifold - this is a cast iron hunk bolted right to the engine, and the cat is bolted to it.
When designing the exhaust system, Mazda (as most car manufacturers do) had a number of objectives -
- It had to be quiet.
- It had to not rust out before the warranty expires
- It had to be relatively inexpensive
- It has to pass VERY strict federal emissions standards
- It has to be easy to install on the assembly line
ALL THOSE factors are looked at BEFORE performance.
With that said, Mazda has traditionally made VERY restrictive mufflers on the RX-7's. Rotaries are VERY loud, and as I'm sure you know your car is VERY quiet. The only way to accomplish this is with a massive, restrictive muffler.
The cat does quite a bit of sound muffling as well. Even if you had no cat-back on the car at all or just straight pipe, the car wouldn't be THAT loud. It would be loud, though
![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
Aftermarket exhausts typically are better built and of higher quality components than stock, and one of their first objectives is making more power. They will be louder than stock, but with just a cat-back, a good exhaust will have a nice, deep, sporty sound, but not loud and obnoxious.
Aftermarket parts to replace the cat are typically called midpipes or straight pipes. Again, grey area, and you can't pass an emissions test with one, but power can be gained there.
The stock exhaust manifold is replaced with headers, which typically is a tubular manifold that keeps the exhaust pulses separate for more power. Many headers are legal - they bolt to the engine, and the cat bolts to the headers.
Right now, there isn't much out there exhaust-wise. In a year, you're gonna see TONS of options - rotary powered vehicles have always attracted enthusiasts, and enthusiasts like modifying cars.
Changing the exhaust should not lead to any reliability problems - just more power and a better sound.
Dale
#29
Originally posted by rodmeister
Is increased noise a necessary consequence of higher performance exhausts? Are there HP gaining exhaust systems without noticable increased sound?
Is increased noise a necessary consequence of higher performance exhausts? Are there HP gaining exhaust systems without noticable increased sound?
In our case, the Borla exhaust for the RX8 has a deeper, throatier exhaust note than stock without it being louder. There is no resonance inside of the cabin, we worked very hard on this.
#30
mostly harmless
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Originally posted by rodmeister
Is increased noise a necessary consequence of higher performance exhausts?
Is increased noise a necessary consequence of higher performance exhausts?
there are other muffling techniques, like resonators, or high-tech mic-and-speaker theoretical systems (like an electronic dynamic resonator) which would just modulate the pressure in the tail pipe in complement to the pressure waves in the exhaust to neutralize any fluctuation, but resonating baffle units aren't necessarily more effective at reducing sound or allowing exhaust to flow unimpeded, and the high-tech solution is as rediculous as it sounds.
edit: actually, not quite. if you have two systems (one a straight through, perforated core muffler and the other a contorted dual-outlet glass pack) which have the ability to reduce noise emissions equally, one exhaust path will inherently have less back pressure than the other. if though, you're comparing two identical exhaust paths, with one absorbing more sound than the other, the louder one will be more effective.
also, the tone of the exhaust note can be changed with the size of the tip you put on the end, not to mention the volume of the resonating chamber and other thingies too...
Last edited by wakeech; 08-28-2003 at 03:38 PM.
#33
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Originally posted by mikeb
are you serious
are you serious
![Confused](https://www.rx8club.com/images/smilies/confused.gif)
Of course I'm serious. I hate those punks that wind out their cars with that annoying rice sound down residential streets at 2AM (a la one ricer at the end of my street), let alone over-blown bass that people install for everybody else's "enjoyment".
Besides flossin' with your car is for people who have nothing else to offer the world. Don't get me wrong, I'm proud of my car, but, no I don't need half the city hearing me coming a mile away....
#34
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I already have the bass (2 12 inch subs) in my 8 and I can't wait to get a mazdaspeed or greddy exhaust. When I do maybe we can meet or I'll see you in San Diego buddy, so you can check it out
#35
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What about the twinloop design used by Mugen? I've heard good things about that design (good power gains with a good sound--not too loud). I'm not even quite sure how it works. Maybe Wakeech or Mr. Borla can elaborate.
Also, Mr. Borla, if you could elaborate on your exhaust system for the RX-8 a little more that would be great.
Also, Mr. Borla, if you could elaborate on your exhaust system for the RX-8 a little more that would be great.
#37
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Originally posted by RotorMotor
Naw, just joshin ya bro...
Of course I'm serious. I hate those punks that wind out their cars with that annoying rice sound down residential streets at 2AM (a la one ricer at the end of my street), let alone over-blown bass that people install for everybody else's "enjoyment".
Besides flossin' with your car is for people who have nothing else to offer the world. Don't get me wrong, I'm proud of my car, but, no I don't need half the city hearing me coming a mile away....
Naw, just joshin ya bro...
![Confused](https://www.rx8club.com/images/smilies/confused.gif)
Of course I'm serious. I hate those punks that wind out their cars with that annoying rice sound down residential streets at 2AM (a la one ricer at the end of my street), let alone over-blown bass that people install for everybody else's "enjoyment".
Besides flossin' with your car is for people who have nothing else to offer the world. Don't get me wrong, I'm proud of my car, but, no I don't need half the city hearing me coming a mile away....
#38
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Originally posted by panda
im guna remove my cats(just 1) tomorrow, just to see what it sounds like :-)
andrew
im guna remove my cats(just 1) tomorrow, just to see what it sounds like :-)
andrew
#39
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I will be bringing my car into the shop for custom exhaust. Only problem is the small outlet that cannot fit canisters rather just smaller tips. also I will be dynoing the performance gains also. hopefully getting a titanium system. BTW: This is all gunna be legal, so no $1000 fines for me
![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
Last edited by Efini 8; 09-02-2003 at 08:34 PM.
#41
Originally posted by Efini 8
I will be bringing my car into the shop for custom exhaust. Only problem is the small outlet that cannot fit canisters rather just smaller tips. also I will be dynoing the performance gains also. hopefully getting a titanium system. BTW: This is all gunna be legal, so no $1000 fines for me
I will be bringing my car into the shop for custom exhaust. Only problem is the small outlet that cannot fit canisters rather just smaller tips. also I will be dynoing the performance gains also. hopefully getting a titanium system. BTW: This is all gunna be legal, so no $1000 fines for me
![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
Will it be a cat-back? How much will it cost for just the materials (titanium)? What do you anticipate the weight savings of titanium will be over stainless? What will the labor costs be? Who is doing the labor? Will they be welding with titanium? Will the flanges be titanium? Whose mufflers will you be buying? Will they be titanium as well? How long will your vehicle be out of commision?
This is a very exciting project. Please keep us posted.
#42
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Which exhaust will yield the largest flames?!
since im all about attention grabbing (duh, i drive an rx8!) , i want to know what kinda flames people are spitting with their aftermarket exhausts. ive heard the borla can yield some good ones at high rpms, but what about any of the other aftermarket exhausts? any pics, vid clips, etc?
i was hanging out with a friend of mine who happens to own a FD....he was making me have flame throwing envy :o
i was hanging out with a friend of mine who happens to own a FD....he was making me have flame throwing envy :o
#44
Administrator
just get a plug and tap it into you exhaust. run power to it with a switch in your dash. whenever you want to shoot flames flick the switch. in some cars you would have to enrich the AF ratio but in this car you won't have to.
#45
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If the guy had a catless FD it doesn't need any "cheating" with plugs in the exhaust. Now, my FD still has its cat, and I've never seen it shoot flames. I'm surprised the RX-8 is doing that with just a cat-back...
jds
jds
#46
Administrator
who's cheating? he wants to shoot flames i gave him the quickest and cheapest way to do it. learned it from my dad and uncles who used to do it to hot rods in the 1950's and i'm sure it was done before that.
#47
Originally posted by KC_RX-8
djmano, just be prepared to be "flamed". Not by me, but all of those "rice-haters" in the world.
djmano, just be prepared to be "flamed". Not by me, but all of those "rice-haters" in the world.
On a related note, I've had comments that the car is Sweet and "what a badass car". Badass a little more than sweet. Is the 8:
Sweet;
Badass; or
Sweet and Badass.
I think it's both at once!
#49
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there is something about the rotarys engine that naturally lets it spit flames. im not really sure what the mecahnics are behind it, maybe someone else on the board can give us a good explanation.
btw.....although attention grabbing gimmicks are usually known as rice i believe that natural bursts of flame out of the tailpipes is not only one of the coolest things you can see, but one of the most indimidating.
btw.....although attention grabbing gimmicks are usually known as rice i believe that natural bursts of flame out of the tailpipes is not only one of the coolest things you can see, but one of the most indimidating.
#50
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Catalytics do everything possible to prevent flames. They take care of all that unburned fuel. As long as they are working, you won't get decent flames(if any at all).
Get rid of the cat and you'll have flames with almost any exhaust. That means you'll need a SESeliminator(02 tricker).
Get rid of the cat and you'll have flames with almost any exhaust. That means you'll need a SESeliminator(02 tricker).