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Old 09-28-2000, 03:37 PM   #1
Sean McElderry
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Post Gutting the cat


Hmmm...I wonder if this is a bad topic since it might be illegal...but since I'm not 100% sure it is illegal, I figure I'd post it anyway. If it's illegal, feel free to remove this post immediately.

Any ideas on how to gut the cat?

I figure I would just unbolt the midpipe, take a screwdriver to the cat's internals, shop-vac the broken pieces outta there, start the car to remove any excess waste, turn the car off, bolt the midpipe back up, and go.

Anything wrong with that process? Keep in mind I only have one cat due to the turbo. Thanks!

Sean
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Old 09-28-2000, 03:46 PM   #2
RidinLow
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Smile

Funny, as I'm reading this topic, my cat is meowing his head off in the kitchen, maybe in protest to your post.
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Old 09-28-2000, 03:47 PM   #3
Sean McElderry
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Post


ROTFL Tell your cat I apologize

Sean
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Old 09-28-2000, 04:08 PM   #4
Keith
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Post

i hate cats. Dogs kick ass
But for your question, if u try it...tell me that doesnt sound so bad. I am interested in doing the same.
Keith
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Old 09-28-2000, 05:14 PM   #5
Keiho
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Why don't you just get a new straight pipe done up? That way you can keep the existing pipe/cat intact in case you ever need it? A new straight pipe shouldn't cost that much.
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Old 09-28-2000, 05:37 PM   #6
johnfelstead
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Hi Sean

Ramming the cat ceramic out is damn hard work. You heed a chisel and lump hammer to smash it to little pieces and then rod it out.

Not sure on the accesibilty of the ceramic on the scoob, sometimes you have to cut them open, smash the crap out of them and then weld them back up.

A replacement pipe is a good idea if emisions testing is an issue. you can just swap over for the test. (shhh i didnt say that )
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Old 09-28-2000, 05:45 PM   #7
MikeYOX
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Have a Nice Day?

Removing a functioning cat at all is a violation of Federal Law. You can gut them, they'll pass most emmisions tests, but it is illegal. Have an "accident" with your stock cat and have it replaced with a better high flow one.
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Old 09-28-2000, 06:03 PM   #8
Nat
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Why not just get a high flow cat? I know they are a bit expensive, but Random Tech. in GA makes awesome high flow cats that make just as much power as straight pipes if I remember correct. A good high flow cat should be only around 5hp down off no cat....and still be good to the environment.
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Old 09-28-2000, 06:11 PM   #9
Gerry
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Well actually i did that to my cats on the camaro. "street race on weekends" It wasn't that bad till I had one cop pull me over at Deer Park Ave "a local crusing spot" go under the car and hit the cat with hid nite-stick. I mean he didn't bother me that the car is tubbed with a 12pt roll cage or even with the blower popping out of the hood ...just my cat..The next thing i know the car is getting towed. Well i don't know what i'm getting at but i'll leave it up to you =0)
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Old 09-28-2000, 06:25 PM   #10
Rich L
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Lightbulb

Hey Sean,

It is illegal... AND its alot of work to bore out the cat (meow!). I would buy a "catless" race pipe, put it on, get the hp...
Then a week befoe inspection... replace it with the stock pipe again.
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Old 09-28-2000, 10:07 PM   #11
Keith
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AHhaha, that sux Gerry. The cops at dpa try to get u for anything possible. Last week they tried to get me for parking in a parking lot that "closes after 10." I just went into to taco bell, and they try to give me a hard time. The sign was like 12", I couldnt even see it. Sometimes they piss me off..they must have a field day that night..pulling over everyone. Oh well..its still a cool place to hang out
Keith
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Old 09-28-2000, 10:31 PM   #12
Civic
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When I had my CRX I just shoved a tire iron through it untill it was gutted. Only bad thing is that it will make your car sound really raspie and hollow sounding.
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Old 09-28-2000, 10:45 PM   #13
8Complex

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Post

Yeah took me a good few hours to clear out the cat on my old Volvo... too bad the damn thing rusted & broke off several days after all that work (wonder what happened to that...).

On the flip side, I know a guy with a Saturn that got a pretty damn big gain out of gutting his cat.
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Old 09-29-2000, 07:23 AM   #14
Big Tee
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I don't have 1st hand knowledge of this but I've heard that 'gutting the cat can cause a mismatch in the readings seen by the upstream and downstream O2 sensors. They then trigger a check engine light. Has anyone experienced this or is it an 'urban legend'?
Took me 30 minues to gut an oil fouled/blocked cat on a Mitsu van a few years ago had no negative affect and reduced ton of back pressure in this context.
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Old 09-29-2000, 08:01 AM   #15
Big Tee
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I have heard that gutting a cat can cause some snafu with the readings between the upstream and downstream o2 sensors that results in thencheck engine light coming on. Has anyone experienced this or is this just an urban legend?
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Old 09-29-2000, 08:02 AM   #16
Big Tee
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I have heard that gutting a cat can cause some snafu with the readings between the upstream and downstream o2 sensors that results in thencheck engine light coming on. Has anyone experienced this or is this just an urban legend?
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Old 09-29-2000, 08:37 AM   #17
rao
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On any OBDII car (MY 97 and later) gutting the cat will result in a perpetual check engine light. BTW, it's also illegal as mentioned above. Also, there is no evidence that a modern cat flows materially less than a stright pipe.
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Old 09-29-2000, 08:46 AM   #18
Geoff
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Post

I actually ran catless for a short period of time; I had to because of the Minnam Stage-2. It came with a "mini cat" that was mostly worthless. Check engine was perpetually on and I couldn't clear it by restarting the car 3X's (The current engine code is "High Pressure Input detected" (About 8psi worth?) - The other code was "Catalyst not functioning within spec."

I had a local muffler shop put in a 2.5" Random Tech Cat ($180), I can now clear the code.

I took the car in today, to have it inspected (Didn't need to, but it was free) - I passed Texas State emissions with flying colors, WITHOUT lowering my fuel mixture via the S-AFC. I was told that I'm running "a little rich" - but that's how I like it.

There were no noticable performance losses after installing the Random Tech. It's also nice to know that my Subie isn't polluting the environment like the SUVs I dislike so much.

-Geoff
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Old 09-29-2000, 08:53 AM   #19
Gearhead_42
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Just a note to any SCCA racers out there, I believe you must use the _OE_ cat (unless the car is more that 5 years old) to maintain your un-modified status in some series (Solo included)

Though if you've already got the turbo, I'm just wasting bandwidth with that comment
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Old 09-29-2000, 09:01 AM   #20
Sean McElderry
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Post

Thank you very much to everyone who replied. I performed the operation last night. The cat is now hollow.

Let me preface this by saying that I would appreciate it if we could keep this to an intellectual discussion regarding the results, rather than a flame war about emissions. If you feel the need to tell me how I am evil, can you please private message me instead? Thank you.

Also, these are the results for my car only. I don't have any other experience with this type of modification on any other car.

Here are the cons:

1) Takes a while.
2) Illegal.
3) Doesn't really smell all that great.

Here are the pros:

1) Car is faster.
2) I hit 10psi of boost at the EXACT same settings, rather than the 8psi that I was hitting earlier.
3) Car is quieter. The empty cat is now acting as a resonator, so the exhaust is very quiet. This was VERY unexpected...but it is the truth.
4) Exhaust gas temperatures are the same at 10psi as they were at 8psi before.
5) Turbo spools up quicker. Full boost is achieved at 3400rpm, which is 300-500rpm quicker than before.

Keep in mind that this was the 3" high flow cat that Minnam includes with their turbo kit. Removing it did make a difference, on my car at least.

Again, thank you for everyone who replied to my original post. See ya!

Sean

[This message has been edited by Sean McElderry (edited September 29, 2000).]
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