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Discussion Starter #1
All legal aspects aside, what are some of the pros and cons of getting rid of the catalytic converter? In specific, sound and performance wise. I'm considering doing this, but want to hear about personal trial and error from everyone else first.
 

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All legal aspects aside, what are some of the pros and cons of getting rid of the catalytic converter? In specific, sound and performance wise. I'm considering doing this, but want to hear about personal trial and error from everyone else first.
Well i havent done this on my Koup (nor will I) but I can go off of experience

Pros
Louder exhaust (possible con)
Less restrictive airflow (can be a con as well, will explain at the end of post)


Cons
Could be TOO loud (could get pulled over all the time, civil complaints, etc.)
Constant check engine light (cats have sensors in them nowadays, my 95 F150 had sensors in the cats)
Less restrictive airflow
Illegal almost ANYWHERE (in the States that is, not sure about anywhere else)

Now about less restrictive airflow, your car would be loud as hell but you will more than likely lose engine back-pressure. If you lose too much engine back-pressure then you lose torque, you lose torque, then you lose take-off power and acceleration.

You could get some of that torque back with a tuning but youd lose hp (not much but youd still lose some)

Also, I mentioned its illegal. Theres something like a $500-$1000 fine for the owner of the car and up to $5000 for the person that performed the cat removal.

Overall, Id say its not worth doing. Hope I helped!
 

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It doesn't work and it's almost certainly illegal. If your state has an emission inspection system you wouldn't pass no how, no way. I'f fogetabout it.

A long time ago I did this and there zero improvement in power or gas economy. Please don't do it and it would pollute the atmosphere. I remember driving through L.A. in 1975 and you could cut the smog with a knife.
 

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Discussion Starter #4
First off, thanks for you honest answer, wasn't sure what sort of responses I would get. You gave me a few things to think about, mainly the possibility of a sensor. That is not something I'd want to deal with, so I'll have to check that out when I get home again.

Would the back pressure drop that significantly if the stock piping and resonator were still on? IF I did this, I'd run the stock size pipe to replace the cat. And I know the noise level would increase, but would it really be a whole hell of a lot more? Again with the stock resonator, piping and a magnaflow muffler...

The legality issue I'm not to worried about as my '92 jeep cherokee was still able to pass emission with just a straight pipe. Haha Yeah, Oregons not very strict... Thanks for the responses so far, got me thinking about some different issues that could arise.
 

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Get an High flow Cat from TurboKit!!!
As for check engine light you could buy some MILS eliminator (some sort of resistor that give constant signal to your ECU from O2 sensor)
 

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Discussion Starter #6
I'd love to...but it's a bit out of my price range. Haha
 

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Get an High flow Cat from TurboKit!!!
As for check engine light you could buy some MILS eliminator (some sort of resistor that give constant signal to your ECU from O2 sensor)
Most, if not all, cars built today use a second HO2S sensor behind the Cat that monitors the exhaust continuously -- if you use the resistor you are referring to you, will still get a SES/CEL because the ECU will detect a constant signal and not a fluctuating signal within prescribed parameters.

I have done the opposite: put in a larger CAT -- 60% larger from a car of the same model with a more powerful engine -- i could not feel a difference in performance AND it did not help me on a 1/4 mile dragstrip! If you are going to keep your original exhaust you really are just wasting time and money changing out the CAT.
 

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You would still lose backpressure and therefore lose takeoff power regardless of piping size. I personally would just leave it alone and get a muffler. The muffler sits so far back from the engine that the backpressure loss would be minimal and not affect the performance of the car.

Now a properly engineered catback exhaust like the one from turbokits.com would increase performance.
 

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Emission controls or inspections are not state mandated but more by the city or county. When I live in Ft Lauderdale FL I had to deal with the emission inspections, but not in Jacksonville and Deleon Springs. It is not inspected and by all the heavy smoking cars I see daily in Knoxville TN it is not enforced here either.

The technical reasons listed by other posters are reason enough to not eliminate the cats. High flow cats or even the cat back exhaust alternatives would be the better option but the cost is a factor.
 

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catless isn't worth it over hifgh flow cat.. less you're turboed and plan on doing a 2 step..

the difference between high flow and catless is only like 1-5 CHP so like 0-2 WHP lol really it's not worth the hassle..

usually catless dps make the car sound raspier and louder ( more ricey) really i wouldn't.. unless your turboed.. and even then cats aren't a bad idea but a catless turboed car can sound sick lol
 

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Discussion Starter #12
Thanks for all the replies! Gave me alot to think about, and after taking all the responses into account, along with some side research, I've decided not to get rid of my cat.

I guess my next step is to find out what the exhaust sounds like without the stock resonator... haha Decisions, decisions! Anyone have a link to a sound clip or video?
 

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there are plenty of videos here on this site, Aidensgrand has one of the nicer sounding exhausts IMO. His is a Magnaflow muffler and you can find those on amazon or ebay for $60-$80
 

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For less than 200$ you could have a Magnaflow (or other brand) muffler install and a greath exhaust tone!
Now witch muffler is best.......that's THE question!!
 

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Discussion Starter #15
Well I currently have a Magnaflow, I'm just looking to get a little more volume out of it. I've heard taking the resonator off makes it louder, but will it change the tone too?
 

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It MIGHT sound more ricey (higher tone, tin canny) but I cant say from experience.

Personally, I might be getting the cat-back kit that Magnaflow made (but hasnt started selling for some reason)
 

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Before I bought my Magnaflow, I tinkered around a little with the stock options and this is what I found: (I have a sedan, and have not tried this on a Koup, so it may be different because the mufflers are different)

The stock resonator is a straight through design and does not change performance one bit being on or off, but DOES make the 'sound'. And it's pretty.

Running just the stock exhaust without the resonator sounds just like... a stock exhaust. It does nothing at all to change anything, because the stock muffler is so restrictive, it chokes the life out of the entire system.

So the 'best' way to deal with this is spend $80 on a Magnaflow 11224 and take it over to the local muffler shop and get them to weld it into place.
 

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So for everybody that says it won't pass emissions this is completely wrong all you have to do go on eBay and look for apart called O2 sensor restrictor and you put that in the place where the O2 sensor goes and then the O2 sensor on end of that it's like a spacer tube and it restricts the flow like a catalyst does to the O2 sensor does not throw a code no more FYI this really does work and they are very cheap are codes will go away just fine not come back and if you hollow out your catalytic converter then nobody can even see it and the codes don't come out so you will pass on the test and on visual test everything will go through just to let you know and this is for Real
 
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