Aftermarket Exhaust Legality

[sandwich14]

Alright, so I know laws are different in different places, but from my research it seems that removing your catalytic converter here in the US is illegal in every state, thanks to the EPA. Unfortunately I'll have to get emissions tested in a few years (not sure how often they make you do it for hybrids), and I don't want to fail and have to change everything back just for that.

So, my question is this:
Upgrading to the P2R downpipe is technically illegal because it removes the catalytic converter. Is upgrading your midpipe still legal? While I think it is, what can I expect from having a larger midpipe/axleback but stock downpipe? Is it even worth upgrading the midpipe if you keep the stock downpipe?

[sleighman]

Well, where are you at. The second cat is after the oxygen sensor so you should still pass an emission test since you have the big one still. The second one from my understanding helps make the CRZ ultra low on emissions. If I am correct when they check for emmisions they are looking for a certain # the car can't be above.

The car runs better without the second cat. Also you don't need a big pipe. You need back pressure for low end torque. A free flowing axle back and the cat delete nets a seat of the pants performance boost. Its best to leave the resonator on the car so you don't get a loud annoying audio hum at 60-80 mph.

Hope that helps.

[sandwich14]

Very good info, thanks! When you say its best to leave the resonator on, or one like it, is that something located in the midpipe? Sorry I'm a noob when it comes to this.

[sleighman]

Yes it is in the mid pipe. If you don't have one in the system you will most likley have a high audio drone in the cabin which is deafening at certain speeds. A resonator is a straight through muffler with baffles and sound deading material in it. The are not usually restrictive.

[B-rad]

Originally Posted by sleighman

Yes it is in the mid pipe. If you don't have one in the system you will most likley have a high audio drone in the cabin which is deafening at certain speeds. A resonator is a straight through muffler with baffles and sound deading material in it. The are not usually restrictive.

I a p 2r missile and down pipe and my drone isn't that loud even at 80

[B-rad]

But I have a twin loop muffler

[sleighman]

I think the twin loop help with a drone. I just know from past experience on 4cyl and V-6's they like to drone without a resonator

[Ludercrz]

Hybrid vehicles are automatically exempt from Emission testing here in Ontario

there is no reason to remove a Cat though, it does not hinder your performance one bit. the part about an exhaust that causes legality issues in some areas comes down to 2 things. Noise and Baffles. in most areas cops will ticket you for Noise or for not having baffles in your exhaust (i.e. a straight exhaust) they find that out by sticking metal wire up the exahaust to see if it stops or not. at least those are the major issues here.

cops can't pull you over for a missing cat but you can get dinged at emissions testing. some people with "hi-flow" Cats still pass emissions if the rest of the car is kept on regular maintenance but again hi-flow cat or regular cat you won't see a big difference and you're just polluting more for nothing.

Resonators also make a big difference in muffling the sound without hindering performance. if you cut a Resonator in half you see that the path is clear and that there is only the addition of sound deadening material:

[sandwich14]

Looks like I'll be getting a midpipe then. I can't seem to find where to buy one. I've heard KSK makes one that will fit with the Noblesse exhaust (which I plan on getting), but its not listed anywhere online...

[B-rad]

Originally Posted by sandwich14

Looks like I'll be getting a midpipe then. I can't seem to find where to buy one. I've heard KSK makes one that will fit with the Noblesse exhaust (which I plan on getting), but its not listed anywhere online...

It's discontinued that's what I have ksk/p2r