Do you guys think there would be any benefit in taking off the second cat on the downpipe and weld in a straight pipe and still run the first cat? Just wondering because I have my own welder and am curious about doing this, the second O2 sensor is right before the 2nd Cat correct.

 

? Theres only one cat on the car

 

There is two on the TC. Atleast Im pretty sure.

 

my bad man! i wasnt even paying attention that it was the TC cobalt. reading>me

 

some hve 2 a bunch of 2.2s have 2 cats.

for emissions.

 

personally id take out both cats. Did that on my SC, should benefit more on TC since turbo runs off exhaust

 

This is true but would make me end up getting a new DP, this way I could just do it myself!

 

I was thinking about taking the stock dp loose from the catback end, and knocking all the crap out of the second cat, as it is right at the end of the dp, with a screwdriver and hammer to gut all the honeycombe material.

the 2nd cat is after the 2nd o2 sensor, so if you gut it, it will not set off any CEL's, plus if you take it down and gut it, when someone looks under the car it looks as if both cats are still there.

did this on a few of my prev cars and it works great.

bang out all the guts of the convertor, and every once in a while start the car up and blow all the crap out of the dp with engine compression untill it all clear, checking with a flashlight.

then bolt it back to the catback and be done, no need to weld in any straight pipe at all.

 

Gutting a cat does increase flow, but it also increases turbulence. If you cut the second cat off and weld in a piece of straight pipe, that would be best. Then you could sell the cat to a recycler for $50.

Question, do these cars really have two cats? If so, why isn't the rear O2 sensor behind the second cat? I heard there's a resonator too. Is what people are thinking a second cat really a resonator or is there 2 cats, a resonator, and then a muffler (going from back to front)?

 

yes there are 2 cats on the TC the 2nd o2 sensor is between them. As to why that is I am sure it probably has to due with it not passing emissions the first time around. I will be getting this done next week I can take pics and video if you want I have already done the muffler delete and that is an amazing mod for cheap.

 

i took the second cat out no codes set

 

Does it sound any different with the second cat out, I already have 3in catback and its really quiet and was looking to make a little more deep tone.

 

I know some people dont wanna spend the money, but getting a catless 3" DP would be best for flow.

 

and i would get a catless downpipe but I definitely would not pass emissions testing

 

Yeah I believe you were saying something the other day about their shitty emissions testing, LOL. TN dont give 2 ***** about emissions, atleast not yet. Quick question for you though, what if I happen to drive up thru IL and they are testing or pull me over for a test? Do they do **** like that?

 

lol no dude. It's only for illinois residents. My buddy has a acura integra type R that he has registered in Idaho so he doesn't have to worry about it. lol

 

i found my car to sound alot like the SRT-4 neon with it straight piped and only one stock cat. i removed the muffler, res, and second cat and its not quiet!

 

WOO!!! I was alittle worried because I was actually born and raised in IL, and usually visit 2 or 3 times per year, so just didnt wanna get stopped.

 

but just to let you know I believe it is illegal to run on a United States Interstate without a catalytic converter

 

Really? My younger Brother has an 05 SRT-4 with stock catback, but he has a 3" catless DP with electric cutout, and with that cutout closed, it sounds really good and is kinda loud, but with it open, it is probably just as loud as my 05 Mustang GT with no cats.

 

Hmm, that is weird, legal in TN, but illegal on TN interstates. I've been stopped by a State Trooper a few years ago, and he didnt say anything about it. Guess they just have to be in one of those moods or doing testing.

 

yeah i wouldn't wory about it if i lived in a place without emissions. I am actually contemplating just going with a catless dp and then changing it back when i go in for emissions testing. They let you know like 3 months in advance before they test you

 

If they let you know 3 months in advance, I would just order and run a 3" catless DP and then keep the stock one and just put it back on before testing. Or if it isnt illegal, just get a 3" DP with a high-flow cat and just keep it on there. Not sure if they expect you to have the same amount of cats as the factory provides or just one.

 

no. It has nothing to do with how many cats. They just want you to have atleast one. It really all comes down to how much hahns catted dp is going to be. If it's over like $400 then screw it i'll just go catless. Just a waiting game for me right now

 

Well atleast you only need one, but if it was me I would just get the catless DP, LOL. Why not order Synapse's catless DP for $350?