General info needed about cat-back exhaust.

[AzNightmare]

I'm thinking of getting a cat-back exhaust for my Mazda3.

I'm not sure which one to go with.
I assume a CorkSport will fit perfectly since they make parts specifically for Mazda. But Borla and Magnaflow seem pretty popular too, but I'm not sure will they fit perfectly for my car, or will some additional custom work need to be done?

And what kind of prices should I be expecting if I bring the cat-back to a shop, and just have them install it?

I did a search, but it seemed like many exhaust threads have people interested in custom exhausts and other cutting/welding work. Plus the threads were quite old and out of date.

I'm just planning to buy the exhaust system and get it "professionally" installed.

Any local shop recommendations?
Seems like Muffler Man was mentioned quite a bit, but others have also said they can occasionally mishandle your parts, depending on who's working on the car.

[SumAznGuy]

It all depends on if the exhaust system is designed for your car or not.

If the Corksport is designed to be a cat back application for your car, it would then be as simple as unbolting the stock exhaust and bolting on the new exhaust system and putting on the rubber hangers.

Borla and Magnaflow should also make bolt-on catback applications for your car.

If you are asking the shop to weld you a custom exhaust using U bend pipes and a universal muffler, then the price may depend on how much work is required.

I am going to assume you want a cat-back application for your car, why don't you buy some beers and pizza, invite some RS members over to your place and have them help you install the muffler. There is no reason you need to go to a muffler shop to have them "professionally" install a catback muffler for you.

[320icar]

^^ this

[AzNightmare]

Based on what I've read, I believe those cat-back will fit right in. I was at the websites and input my car info and those were the exhausts that showed up.

I would feel more comfortable getting the exhaust installed at a shop. It would give me better piece of mind should anything go wrong in the future. My car is about 10 years old, so parts could be rusted and more work required.

I guess it really depends on the price, but I'm assuming it's not going to be ridiculous if I get a bolt on done at a shop?

[AzNightmare]

I was checking the Corksport website and there's a $200 diff between these two.

No Catalyst


With High Flow Catalyst


I assume it has something to do with this?

Installation of the exhaust requires the removal of the stock second un-monitored catalyst. Removal of a catalyst on a street vehicle is illegal thus this system is not sold for street use. If you select the catalyst option the exhaust will come with a high flow metallic substrate catalyst which will be compliant with most states emissions.

I was looking at this too:


It says "Bolt-in exhaust kit requires no cutting or welding"



So I'm not sure what's the difference between these options...

[LP700-4]

From the 2 corksport options one has a cat and one doesnt lol. Catless will have more power gains? But exhaust might smell sometimes and not sure if aircare will be passed as there wont be a CEL but they look under the car? Not too big of a deal since aircare is done in a couple months.

Corksport one isnt really a cat back as it replaces the cat, believe it would be a de-cat exhaust.

[AzNightmare]

I prefer not to do any cutting or welding. So if I ever need to make my car stock again, I can do it without cutting.

Would you recommend the Borla in this case?

[LP700-4]

None of them require cutting or welding. All of them should be direct bolt-ons and come off the same way.

Since your car already has the secondary cat, all the corksport ones would do is take off the OEM cat and replace it either with the test pipe (no cat) or the high flow cat. The catback from there on is the same between the catted and decatted.

Its hard to recommend one as it depends on what tone and or loudness you want from your car. You do gain more power without the cat if that is what you are looking for.

[SumAznGuy]

Assuming your car is an 05 Mazda 3, your stock exhaust has a primary cat built into the exhaust manifold


The cat-back exhaust replaces this part


No cutting or welding is needed to install it.

From what I can tell by these pics, you may not need the second cat.

[AzNightmare]

Thanks for all the replies so far... I'm pretty noob with this stuff, so try to bear with me. (I'm doing tons of "homework" online before I post in here)

Originally Posted by LP700-4

None of them require cutting or welding. All of them should be direct bolt-ons and come off the same way.

Since your car already has the secondary cat, all the corksport ones would do is take off the OEM cat and replace it either with the test pipe (no cat) or the high flow cat. The catback from there on is the same between the catted and decatted.

Its hard to recommend one as it depends on what tone and or loudness you want from your car. You do gain more power without the cat if that is what you are looking for.

Based on YouTube research, I'm happy with the Borla or Corksport exhaust tone. I don't want my car to be excessively loud, and I don't want to deal with swapping out a test pipe every time my car goes in for aircare.

Based on the Borla picture posted above, I see 2 "bigger" sections. But I'm getting confused if one is a muffler, or a cat, etc?

Originally Posted by SumAznGuy

Assuming your car is an 05 Mazda 3, your stock exhaust has a primary cat built into the exhaust manifold


The cat-back exhaust replaces this part


No cutting or welding is needed to install it.

From what I can tell by these pics, you may not need the second cat.

Is the first diagram a stock 2005 mazda3 exhaust system?
I can see the (1) is the primary built-in cat you mentioned. What is the (2)?

Is the second diagram, is the (1) the muffler? And is that the entire thing I'm replacing with the aftermarket exhaust?


If I keep my OEM cat that's built into the exhaust manifold, can I get the Corksport test pipe version, but just not use the test pipe, and attach the rest of the exhaust system to my OEM cat (without welding)? I don't think spending $200 for a hi-flow cat seems necessary, but using the test pipe makes my car not street legal, too loud, and smell bad.

The diagrams helped a lot, and I think I'm slowly starting to get it... Kind of feels like LEGO, but I just need to figure out how all this connects together.

[nma]

Why do you want an exhaust? Don't be scared to do it your self man, it's literally just unbolting some pipes and bolting new ones on.. Not much can go wrong

[AzNightmare]

Originally Posted by nma

Why do you want an exhaust? Don't be scared to do it your self man, it's literally just unbolting some pipes and bolting new ones on.. Not much can go wrong

Sportier sounding car, and minor performance gain as a bonus.

I'm more interested in learning about the exhaust system in general and figuring out the correct parts I need to use to buy.

Normally I'm a pretty hands-on kind of guy, but I don't have the tools to do work under the car, including the tools to lift the car.
If I can borrow some jack stands and take a look under my car, I can get a better idea.


Anyway, for now, I'll figure out what I need to get first before I think about the installation part.

[SumAznGuy]

Originally Posted by AzNightmare

I don't want to deal with swapping out a test pipe every time my car goes in for aircare.

In theory, aircare is supposed to be over by Jan 1 2015 so you may not need to worry about this anymore.

Based on the Borla picture posted above, I see 2 "bigger" sections. But I'm getting confused if one is a muffler, or a cat, etc?

Is the first diagram a stock 2005 mazda3 exhaust system?
I can see the (1) is the primary built-in cat you mentioned. What is the (2)?

Is the second diagram, is the (1) the muffler? And is that the entire thing I'm replacing with the aftermarket exhaust?

Part #2 of the first picture is the resonator, which is the first round part is the second pic.
Part #2 in the second picture is the muffler. From that point on, it is all pipe and the bigger tip.

If I keep my OEM cat that's built into the exhaust manifold, can I get the Corksport test pipe version, but just not use the test pipe, and attach the rest of the exhaust system to my OEM cat (without welding)? I don't think spending $200 for a hi-flow cat seems necessary, but using the test pipe makes my car not street legal, too loud, and smell bad.

You still have the stock cat in the exhaust manifold so you won't get the stink. But it doesn't mean the test pipe will not get you a VI or a fail from air crap because police officers/Aircare employees may not know the exact specs of a stock 05 Mazda 3 exhaust system.

[AzNightmare]

Yeah, I'm not really interested in doing anything to the car that gives the police any reason to give me a fine/impound, even if it's subtle and unlikely.

Upon further research, I believe my car's stock exhaust is one piece, which means cutting will be mandatory...

I'm currently looking at a few exhausts.
2.4", 2.5", 2.35"...

Will these sizes really make that much of a difference?

I've heard some people say if the exhaust is too big, you might end up losing power or torque? I think my stock exhaust is 1-7/8"

[SumAznGuy]

In my other post, picture one. There is the oval thing just before the big round thing at the end.
That is where you bolt the exhaust to the exhaust manifold.
Your stock exhaust may be one piece, but it is not one piece with the exhaust manifold and cutting is not required.

The flange is to your left in this picture.
They only chopped the rear pipe from the exhaust because it would have been that much longer.

I repeat for the last time, no cutting is required unless you plan on keeping the stock exhaust.

Here is a better pic of the stock exhaust uncut.


And here is a pic of the flange that bolts onto to the stock exhaust manifold.


As for pipe diameter, don't worry too much about it. You are not racing the car so don't worry about every last HP. And you, with the larger diameter piping, you will lose some torque as there is less back pressure.
The Corksport is 2.4 inch ID, which should be plenty fine and not too big that you'll lose too much torque.

[AzNightmare]

Originally Posted by SumAznGuy

In my other post, picture one. There is the oval thing just before the big round thing at the end.
That is where you bolt the exhaust to the exhaust manifold.
Your stock exhaust may be one piece, but it is not one piece with the exhaust manifold and cutting is not required.

The flange is to your left in this picture.
They only chopped the rear pipe from the exhaust because it would have been that much longer.

I repeat for the last time, no cutting is required unless you plan on keeping the stock exhaust.

Here is a better pic of the stock exhaust uncut.


And here is a pic of the flange that bolts onto to the stock exhaust manifold.

I did some more research...
It seems like all the aftermarket bolt-on exhausts (borla, magnaflow, racing beat) are designed to keep the (2nd) OEM cat.
Which makes sense as they're cat-back systems.

Those aftermarket exhausts only come with a resonator and a muffler,
besides the Corksport which gives me either a test pipe or high-flow cat to replace my 2nd OEM cat.
So CS is more like a de-cat, as someone mentioned earlier, rather than a cat-back.

I think the "flaw" with my car's exhaust is that the flange is before the 2nd cat. Not after.
Therefore there's no way to keep the 2nd cat without cutting.
The instructions for every aftermarket exhaust tells me to make a cut after the 2nd OEM cat.
I don't seem to have much of a choice unless I buy an aftermarket cat.
But on the flip side, if I must cut, what's the worst that can happen?
If I ever need to go back to stock, is it as simple as a welding job?

Originally Posted by SumAznGuy

As for pipe diameter, don't worry too much about it. You are not racing the car so don't worry about every last HP. And you, with the larger diameter piping, you will lose some torque as there is less back pressure.
The Corksport is 2.4 inch ID, which should be plenty fine and not too big that you'll lose too much torque.

Lose torque as in, compared to my stock exhaust?
or lose torque compared to a smaller ID aftermarket exhaust?

I'm not racing, so I don't need to squeeze out every bit of HP,
but it seems kind of counter-productive if I'm getting less torque than stock.
won't that mean it's harder to pass traffic with an aftermarket exhaust?




Also, what is BC's stance on aftermarket exhausts and SRI, etc.
California seems pretty anal with their CARB law, but does BC have something equivalent to it?