Re: Removing "cat" from older car?
[Re: Faust]
#2990861
12/01/21 01:43 PM
12/01/21 01:43 PM
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Joined: Jan 2011
Posts: 15,840 Central Florida
larrymopar360
Stud Muffin
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Stud Muffin
Joined: Jan 2011
Posts: 15,840
Central Florida
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I have a very low mileage '85 Caddy Seville. It is time for a new muffler and I am wondering about removing the catalytic converter. Will this make any difference? The car is severely underpowered and even 5 hp would be noticeable. Is there any other antique smog equipment I can remove? My state does not check cars this age. this is the 4.1, not the 8-6-4. I'd say yes especially if it's original CAT because it may be clogged. You could hollow it out and put it back on. Take a steel rod like piece of rebar and hollow it out or a piece of replacement pipe and you'll get a bit better flow but probably only notice the sound difference and not the extra hp.
Facts are stubborn things.
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Re: Removing "cat" from older car?
[Re: A12]
#2990957
12/01/21 06:51 PM
12/01/21 06:51 PM
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Joined: Feb 2009
Posts: 802 Houston, Texas
racerx20
Standard but OK
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Standard but OK
Joined: Feb 2009
Posts: 802
Houston, Texas
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I know on the 80's Mopar there is only one O2 sensor pre-cat, my 88 CSX-T is cat-less and doesn't know the difference.
1972 Road Runner
1988 Shelby CSX-T
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Re: Removing "cat" from older car?
[Re: moparjim79]
#2990983
12/01/21 08:13 PM
12/01/21 08:13 PM
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Joined: Jan 2003
Posts: 10,538 Freeport IL USA
poorboy
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,538
Freeport IL USA
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About the cats, I pulled a clogged cat off of my mothers Dodge minivan in early Nov, this year (she replaced it with a new one, her money). That OEM cat, at the junk yard, was worth $300, I suspect if I would have resisted a bit, I believe could have gotten more! Before you cut one up, might want to see what its worth scrap. Gene
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Re: Removing "cat" from older car?
[Re: poorboy]
#2991067
12/01/21 10:03 PM
12/01/21 10:03 PM
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Joined: Jan 2003
Posts: 2,378 Massachusetts
Faust
OP
top fuel
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OP
top fuel
Joined: Jan 2003
Posts: 2,378
Massachusetts
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About the cats, I pulled a clogged cat off of my mothers Dodge minivan in early Nov, this year (she replaced it with a new one, her money). That OEM cat, at the junk yard, was worth $300, I suspect if I would have resisted a bit, I believe could have gotten more! Before you cut one up, might want to see what its worth scrap. Gene Yes, I understand "factory" cats are worth a good piece of change. Aftermarket replacements, not so much. About the druggies someone else mentioned. Without a doubt. I live near a commuter rail station. Not safe to park a modern pick up there, they cut the cats off with a battery Sawzall.
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Re: Removing "cat" from older car?
[Re: moparjim79]
#2991075
12/01/21 10:14 PM
12/01/21 10:14 PM
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Joined: Jan 2003
Posts: 2,378 Massachusetts
Faust
OP
top fuel
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OP
top fuel
Joined: Jan 2003
Posts: 2,378
Massachusetts
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I can only speak from experience- parents had an 85 coupe de ville with the 4.1. Its a massive turd. You could do a bunch of stuff to it, but naturally aspirated its a dump box, and are infamous for rear main leaks. Yeah, no power, I think 150hp. That is why I was looking for even 5hp. Car & engine only have 60K, so far, so good. I like it (I know it is love it, or hate it) and may swap the engine when I have more energy. It looks like this one, except later alloy wheels. I just stole the picture, no idea about the other cars.
Last edited by Faust; 12/01/21 10:15 PM.
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Re: Removing "cat" from older car?
[Re: larrymopar360]
#2991247
12/02/21 12:58 PM
12/02/21 12:58 PM
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Joined: Jan 2003
Posts: 9,113 Tucson, AZ
Ramrod39
My New Title
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My New Title
Joined: Jan 2003
Posts: 9,113
Tucson, AZ
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I'd say yes especially if it's original CAT because it may be clogged. You could hollow it out and put it back on. Take a steel rod like piece of rebar and hollow it out or a piece of replacement pipe and you'll get a bit better flow but probably only notice the sound difference and not the extra hp. We used to do this back in the day when cats got clogged up. They also used to sell "test tubes", pieces of pipe that bolted in to replace cats. Marketed as a diagnostic tool to run while you ordered a new cat. Guess how often the test tubes were removed...
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Re: Removing "cat" from older car?
[Re: Ramrod39]
#2991249
12/02/21 01:02 PM
12/02/21 01:02 PM
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Joined: Jan 2003
Posts: 2,378 Massachusetts
Faust
OP
top fuel
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OP
top fuel
Joined: Jan 2003
Posts: 2,378
Massachusetts
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[quote=larrymopar360
We used to do this back in the day when cats got clogged up. They also used to sell "test tubes", pieces of pipe that bolted in to replace cats. Marketed as a diagnostic tool to run while you ordered a new cat. Guess how often the test tubes were removed... Yeah, I remember those in the J.C. Whitney catalogs, remember those?
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Re: Removing "cat" from older car?
[Re: Faust]
#2991597
12/03/21 12:03 PM
12/03/21 12:03 PM
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Joined: Sep 2003
Posts: 19,366 north of coder
moparx
"Butt Crack Bob"
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"Butt Crack Bob"
Joined: Sep 2003
Posts: 19,366
north of coder
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in my experience "unclogging" cats, most guys just do the "jam a pipe into them" pick out the big chunks, and call it done. then said "jammers" complain afterward the car ran better, but it's now back to where it was, or worse. the problem with doing this on the car [or off for that matter] is you get the big chunks, but not all of the material. what's left will eventually find it's way to the muffler, then clog it up, choking off the exhaust. the only sure fire way was mentioned above. take the cat off, cut open the top, remove the material, then weld the top back on. that way, you can be sure all the material is gone. or get a "test pipe" [made or bought] installed. i have fixed too many "jammer" repairs over the years, and heard them cry about buying new mufflers. anyone that talks about punching out cats these days, i just tell them to not come back complaining to me when the car starts to run worse than before.
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Re: Removing "cat" from older car?
[Re: Faust]
#2991636
12/03/21 01:24 PM
12/03/21 01:24 PM
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Joined: Jan 2003
Posts: 4,712 Moved to N.E. Tennessee
GomangoCuda
master
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master
Joined: Jan 2003
Posts: 4,712
Moved to N.E. Tennessee
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When I read the title of this thread a totally different image went through my head. A long time ago my wife's brother asked thier dad if he could borrow his car to go on a date. Dad said you have a good car , take it. He said but my car stinks real bad I can't take it on a date. Dad says let's find out why it stinks. They opened the hood and there was a dead cat laying on the intake manifold. Dad tried to pull the cat out by the leg and the leg just pulled out like an overdone turkey drumstick.
In theory, there is no difference between theory and practice. In practice, there is.
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Re: Removing "cat" from older car?
[Re: GomangoCuda]
#2991766
12/03/21 06:49 PM
12/03/21 06:49 PM
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Joined: Jan 2003
Posts: 2,378 Massachusetts
Faust
OP
top fuel
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OP
top fuel
Joined: Jan 2003
Posts: 2,378
Massachusetts
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When I read the title of this thread a totally different image went through my head. A long time ago my wife's brother asked thier dad if he could borrow his car to go on a date. Dad said you have a good car , take it. He said but my car stinks real bad I can't take it on a date. Dad says let's find out why it stinks. They opened the hood and there was a dead cat laying on the intake manifold. Dad tried to pull the cat out by the leg and the leg just pulled out like an overdone turkey drumstick. When I was a kid, I found a cat trapped between my battery and the hood.
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Re: Removing "cat" from older car?
[Re: Faust]
#2991831
12/03/21 10:00 PM
12/03/21 10:00 PM
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Joined: Feb 2003
Posts: 4,794 Castlegar, BC, Canada
That AMC Guy
master
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master
Joined: Feb 2003
Posts: 4,794
Castlegar, BC, Canada
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I had no choice but to remove the cat from the '88 Dodge Ram V6 I've been putting back together. Not only did the truck not come with a cat, an OE one is not available and aftermarket ones are pointless since the truck is over 25 years old and exempt! Some vehicles, it's as easy as cutting them out, and welding in pipe. Some vehicles, like my Ram, had an air tube run from the air pump and not only pumped air into the manifolds, it pumped air into the cat as well. These are the ones you gotta watch out for because you don't want those air pipes turning into exhaust leaks. Since my air pump was also gone, I figured I'd delete the tubing and plug off the manifolds. Well, those plugs would've wound up being really odd sizes and drilling the holes bigger in my case, just wasn't an option. Not only that, a y-pipe for the V6 Ram is unobtainium. But I could find a y-pipe from a Dakota.... but that necessitated finding Dakota manifolds. THAT actually turned out to be a stroke of luck because '94-and-up manifolds no longer have the air injection ports. But then, I needed a Dakota trans dipstick tube. because the one for the Ram manifolds ran right where the Dakota manifolds run. Ugh. What a debacle. Luckily it all worked out in the end.
Bloody Mary, Full of Vodka, Blessed art thou among cocktails....
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Re: Removing "cat" from older car?
[Re: moparx]
#2991912
12/04/21 08:52 AM
12/04/21 08:52 AM
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Joined: Jan 2003
Posts: 8,021 Tulsa OK
Bad340fish
master
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master
Joined: Jan 2003
Posts: 8,021
Tulsa OK
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in my experience "unclogging" cats, most guys just do the "jam a pipe into them" pick out the big chunks, and call it done. then said "jammers" complain afterward the car ran better, but it's now back to where it was, or worse. the problem with doing this on the car [or off for that matter] is you get the big chunks, but not all of the material. what's left will eventually find it's way to the muffler, then clog it up, choking off the exhaust. the only sure fire way was mentioned above. take the cat off, cut open the top, remove the material, then weld the top back on. that way, you can be sure all the material is gone. or get a "test pipe" [made or bought] installed. i have fixed too many "jammer" repairs over the years, and heard them cry about buying new mufflers. anyone that talks about punching out cats these days, i just tell them to not come back complaining to me when the car starts to run worse than before. Some people are lazy, you gotta jam that pipe through, then drop it a few times, then jam it again, don't stop until you can see clean metal around the edges lol. Or so I have heard.
68 Barracuda Formula S 340
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