N00b question... please don't make fun of me. :P

[OnionTou]

I want to eventually swap out all my exhaust system (From the header all the way to the exhaust). There is so much variety it gets confusing.

So far I have ordered an exhaust:

Invidia N1 Catback

I just wanted to make sure I know the pieces I need and what order they are located in the exhaust system. I know there are gaskets and connectors to be considered at each point.

1) Header (connects to the engine block)
2) Overpipe?
3) Frontpipe?
4) Exhaust

Am I missing any part?

The catalytic converter is located in the front pipe?

I think I've read that the car also monitors the exhaust to check on how the engine is burning up the fuel, this sensor is located where?

Any suggestions on what to think about when choosing the parts? (besides bigger diameter to get a better flow?)

[husker741]

Front to back: Header, overpipe, front pipe, mid pipe (which is included with your N1), and then muffler.

O2 sensors are in the header (exhaust manifold). There is a cat in the header and front pipe. I chose to get a front pipe that has a high-flow cat to keep down rasp and smell. So I still have 2 cats.

Unless you are going turbo down the road, stick with 2.5 inch, especially because your N1 is 2.5 inch.

[PERRIN]

Here is a diagram we put together when the twins first came out.

There are two cats on the BRZ/FR-S the first cat in the header and the second cat in the front pipe.
There are two O2 sensors, they are both in the header one before the first cat and one after the first cat.

Hope that helps

[PERRIN]

@husker741, you beat me to it

[vividracing]

Noob questions welcomed. We are all here to support you.

Originally Posted by OnionTou

I want to eventually swap out all my exhaust system (From the header all the way to the exhaust). There is so much variety it gets confusing.

So far I have ordered an exhaust:

Invidia N1 Catback

I just wanted to make sure I know the pieces I need and what order they are located in the exhaust system. I know there are gaskets and connectors to be considered at each point.

1) Header (connects to the engine block)
2) Overpipe?
3) Frontpipe?
4) Exhaust

Am I missing any part?

The catalytic converter is located in the front pipe?

I think I've read that the car also monitors the exhaust to check on how the engine is burning up the fuel, this sensor is located where?

Any suggestions on what to think about when choosing the parts? (besides bigger diameter to get a better flow?)

[OnionTou]

how much does it hurt (emissions wise) to have or not have the catalytic converter?

My engine mods will only go intake, and all the exhaust system.

I'm guessing if I do an ecu tune that will have a greater effect on my emissions than the regular mods?

[husker741]

Originally Posted by OnionTou

how much does it hurt (emissions wise) to have or not have the catalytic converter?

My engine mods will only go intake, and all the exhaust system.

I'm guessing if I do an ecu tune that will have a greater effect on my emissions than the regular mods?

Unless you're required by law to get an emissions test, don't worry about it. If you do headers and intake, definitely get a tune. That won't do anything for emissions. Like I said, I got a catted front pipe only to keep down rasp and smell.

[SkAsphalt]

Originally Posted by husker741

Unless you're required by law to get an emissions test, don't worry about it. If you do headers and intake, definitely get a tune. That won't do anything for emissions. Like I said, I got a catted front pipe only to keep down rasp and smell.

and that smell comes from the harmful emissions

[husker741]

Originally Posted by SkAsphalt

and that smell comes from the harmful emissions

Well yeah, but we aren't talking about a Prius here.

[Trashed675]

Rasp isn't always dictated by the cats. I have a full borla system with no cats and I have no rasp. It does drone a little in certain situations though, but not bad.

[husker741]

Originally Posted by Trashed675

Rasp isn't always dictated by the cats. I have a full borla system with no cats and I have no rasp. It does drone a little in certain situations though, but not bad.

True. Resonators can also help with rasp. However, I know someone else with a full Borla system from header to axle and there's a ton of rasp. Cats and resonators will help.

[FR-S Matt]

If you're tuned, you need to flash back to stock before doing inspection. The secondary O2 system is disabled and you'll fail the test before it even starts. (Trust me, I learned at the dealership trying to get my inspection sticker I never got when I bought the car). Keep a cat in your front pipe, especially since most headers are all catless. Don't be that jerk that has the nasty smelling exhaust and you get black soot around your bumper from running completely catless.


You guys forgot pipe sizing also to take into consideration with rasp. The bigger the piping, the more rasp prone. Doesn't matter how many resonators you have in the system, or a cat.

[SirBrass]

Originally Posted by husker741

Front to back: Header, overpipe, front pipe, mid pipe (which is included with your N1), and then muffler.

O2 sensors are in the header (exhaust manifold). There is a cat in the header and front pipe. I chose to get a front pipe that has a high-flow cat to keep down rasp and smell. So I still have 2 cats.

Unless you are going turbo down the road, stick with 2.5 inch, especially because your N1 is 2.5 inch.

What about super charged? Stick with 2.5" or go ahead and do the prep upgrade to 3"?

Originally Posted by FR-S Matt

If you're tuned, you need to flash back to stock before doing inspection. The secondary O2 system is disabled and you'll fail the test before it even starts. (Trust me, I learned at the dealership trying to get my inspection sticker I never got when I bought the car). Keep a cat in your front pipe, especially since most headers are all catless. Don't be that jerk that has the nasty smelling exhaust and you get black soot around your bumper from running completely catless.

If the secondary system is disabled in order to not throw a CEL, then they can't tell it's disabled. No way no how. Not without examining the ROM. If it doesn't throw a code, things show green. And in certain areas, if you aren't throwing ODBII codes, then your car never even goes on the sniffer in the state inspection.

[husker741]

Originally Posted by SirBrass

What about super charged? Stick with 2.5" or go ahead and do the prep upgrade to 3"?

Superchargers are fine to use 2.5. However, they will still benefit from 3 inch.