YACT: Anyone install a "Test Pipe" & remove the Catalyic Converter?

Analog

Lifer
Jan 7, 2002
12,755
3
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I have an '89 Blazer 4x4 (full size w/350 V8) that is a rust bucket, but I want to use it for off-road use and plowing around the farm (its not licensed any longer for on-road use).

Since I like to "tinker", I thought about cutting off the Cat and putting in a "test pipe". Anyone ever do this?

Is it as basic as cutting it off and putting a piece of pipe in?

thx.

BTW, I believe it is legal, as long is it is not used on public roads.
 

cavemanmoron

Lifer
Mar 13, 2001
13,664
28
91
Originally posted by: yellowfiero
I have an '89 Blazer 4x4 (full size w/350 V8) that is a rust bucket, but I want to use it for off-road use and plowing around the farm (its not licensed any longer for on-road use).

Since I like to "tinker", I thought about cutting off the Cat and putting in a "test pipe". Anyone ever do this?

Is it as basic as cutting it off and putting a piece of pipe in?

thx.

BTW, I believe it is legal, as long is it is not used on public roads.

:thumbsup:
 

lokiju

Lifer
May 29, 2003
18,526
5
0
I had it done on my '98 blazer, all that was done was to cut the cat off and put a straight piece of pipe in.

Nothing to it really.

 

RgrPark

Golden Member
Mar 11, 2000
1,086
0
0
i believe that a lot of people that are "performance minded" do this. Usually doesn't involved cutting, just unbolt the cat section of the pipe and attach a bolt on.

Just make sure you passed your states's emissions testing before you do this.
 

alkemyst

No Lifer
Feb 13, 2001
83,769
19
81
Those talking 1996 and newer vehicles would have had a check engine light come on and possibly poorer performance.

OBDII computers read before and after the CAT and adjust accordingly.

There are easy ways to defeat the problems, but it's not just a hack and weld job like older cars.

 

Insane3D

Elite Member
May 24, 2000
19,446
0
0
I haven't had cats on my Mustang for like 9 years now, and it's my daily driver. It all depends on who inspects it and whether or not you have emissions testing...
 

alkemyst

No Lifer
Feb 13, 2001
83,769
19
81
Originally posted by: Insane3D
I haven't had cats on my Mustang for like 9 years now, and it's my daily driver. It all depends on who inspects it and whether or not you have emissions testing...

Still FEDERALLY ILLEGAL in all 50 states whether you have inspections or not for any street driven vehicle.

People steal music and videos all the time too, just because they are getting away with it, doesn't mean it's ok.

That said I am willing to bet your cat-free mustang is less a smog machine than some of these 70's-80's hoopie's moving down the highway.
 

Brutuskend

Lifer
Apr 2, 2001
26,558
4
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I once worked at a muffler shop, so yeah I've done it.

When the boss tried to screw me over I told him I had been keeping a record of all the cars/trucks he had told me to do this too.

I straightened RIGHT UP after that. :)

(BTW I was bluffing ;) )

(edit) Knocking the guts out of the cat is probably the best in most cases since then if someone looks at the exhaust it LOOKS copacetic!
 

iamwiz82

Lifer
Jan 10, 2001
30,772
13
81
Originally posted by: RgrPark
i believe that a lot of people that are "performance minded" do this. Usually doesn't involved cutting, just unbolt the cat section of the pipe and attach a bolt on.

Just make sure you passed your states's emissions testing before you do this.

Trying to unbolt any exhaust related bolts on a 16 year old Michigan vehicle is not going to work ;)
 

Brutuskend

Lifer
Apr 2, 2001
26,558
4
0
Originally posted by: iamwiz82
Originally posted by: RgrPark
i believe that a lot of people that are "performance minded" do this. Usually doesn't involved cutting, just unbolt the cat section of the pipe and attach a bolt on.

Just make sure you passed your states's emissions testing before you do this.

Trying to unbolt any exhaust related bolts on a 16 year old Michigan vehicle is not going to work ;)

Take a torch to the bolts until they are cherry red and they will usually come right off.
 

Zenmervolt

Elite member
Oct 22, 2000
24,512
22
81
Originally posted by: Brutuskend
Take a torch to the bolts until they are cherry red and they will usually come right off.
Ahh, the blue wrench. Amazing tool. :)

ZV
 

iamwiz82

Lifer
Jan 10, 2001
30,772
13
81
Originally posted by: Brutuskend
Originally posted by: iamwiz82
Originally posted by: RgrPark
i believe that a lot of people that are "performance minded" do this. Usually doesn't involved cutting, just unbolt the cat section of the pipe and attach a bolt on.

Just make sure you passed your states's emissions testing before you do this.

Trying to unbolt any exhaust related bolts on a 16 year old Michigan vehicle is not going to work ;)

Take a torch to the bolts until they are cherry red and they will usually come right off.

Never had any luck, even with a torch. I usually end up cutting the bolts.
 

cavemanmoron

Lifer
Mar 13, 2001
13,664
28
91
Originally posted by: iamwiz82
Originally posted by: Brutuskend
Originally posted by: iamwiz82
Originally posted by: RgrPark
i believe that a lot of people that are "performance minded" do this. Usually doesn't involved cutting, just unbolt the cat section of the pipe and attach a bolt on.

Just make sure you passed your states's emissions testing before you do this.

Trying to unbolt any exhaust related bolts on a 16 year old Michigan vehicle is not going to work ;)

Take a torch to the bolts until they are cherry red and they will usually come right off.

Never had any luck, even with a torch. I usually end up cutting the bolts.


I took the stock exhaust off my 1964 Valiant last year,
the bolts at the manifold's to the Y pipe unbolted!! :Q:cool:

One muffler clamp broke,LOL.

I then took it to Midas,and had Dual exhaust put on,sounds much better,
with Dual turbo mufflers.:)
 

mercanucaribe

Banned
Oct 20, 2004
9,763
1
0
Even if it is legal, I don't see why you would do that. You'll increase emissions by hundreds of percentage points, for a miniscule amount of horsepower. People have no damn morals anymore.
 

Shawn

Lifer
Apr 20, 2003
32,236
53
91
I drove around with a test pipe for a while and it was horrible. My exhaust sounded like a crappy buzzing fart can and my car smelled like ass everywhere I went. So I put my cat back on. Not worth it. Especially since you are polluting 100x more.
 

Analog

Lifer
Jan 7, 2002
12,755
3
0
Originally posted by: Shawn
I drove around with a test pipe for a while and it was horrible. My exhaust sounded like a crappy buzzing fart can and my car smelled like ass everywhere I went. So I put my cat back on. Not worth it. Especially since you are polluting 100x more.


I thought cats make your car smell like rotten eggs.
 

gar3555

Diamond Member
Jan 8, 2005
3,510
0
0
I did with my 91 Chevy 1/2 ton 4x4, it just has a straight aluminum pipe where the cat used to be, it doesn't sound bad at all with my flowmaster, also get some tube headers for max flow.
My truck isn't tagged either, and it is for off road use only, hope you plan on swapping out that crappy IFS front end, that is what I'm working on right now.
 

Shawn

Lifer
Apr 20, 2003
32,236
53
91
Originally posted by: yellowfiero
Originally posted by: Shawn
I drove around with a test pipe for a while and it was horrible. My exhaust sounded like a crappy buzzing fart can and my car smelled like ass everywhere I went. So I put my cat back on. Not worth it. Especially since you are polluting 100x more.


I thought cats make your car smell like rotten eggs.

No, they burn off that smell.
 

Pepsi90919

Lifer
Oct 9, 1999
25,162
1
81
Originally posted by: yellowfiero
Originally posted by: Shawn
I drove around with a test pipe for a while and it was horrible. My exhaust sounded like a crappy buzzing fart can and my car smelled like ass everywhere I went. So I put my cat back on. Not worth it. Especially since you are polluting 100x more.


I thought cats make your car smell like rotten eggs.

you'd think someone would've noticed by now?
 

Insane3D

Elite Member
May 24, 2000
19,446
0
0
Originally posted by: mercanucaribe
Even if it is legal, I don't see why you would do that. You'll increase emissions by hundreds of percentage points, for a miniscule amount of horsepower. People have no damn morals anymore.

You also must not realize that if the car is running properly and in tune, it will run cleaner and more efficient without cats. Cats increase backpressure, and are there to compensate for people who never do any tune ups on their cars, or care how they run.

I've had my car on an emissions machine before and after I had removed the cats. I did better on all but one reading without cats. I get better gas mileage as well.

This has nothing to do with "morals"...

:roll:
 

Insane3D

Elite Member
May 24, 2000
19,446
0
0
Originally posted by: alkemyst
Originally posted by: Insane3D
I haven't had cats on my Mustang for like 9 years now, and it's my daily driver. It all depends on who inspects it and whether or not you have emissions testing...

Still FEDERALLY ILLEGAL in all 50 states whether you have inspections or not for any street driven vehicle.

People steal music and videos all the time too, just because they are getting away with it, doesn't mean it's ok.

That said I am willing to bet your cat-free mustang is less a smog machine than some of these 70's-80's hoopie's moving down the highway.


Technically illegal yes, but I haven't had any FBI agents looking under my car recently...:p

 

NeoPTLD

Platinum Member
Nov 23, 2001
2,544
2
81
I know it's not for street use, but I will add this anyways.
In Oregon, newer cars with OBDII only has to pass a plug-in computer read out test. So if the sensor readings can be defeated by using signal injector. Pre-1996 and post 1981(I think...) cars get tested by gas probe in the tail pipe on a dyno and there's really no way to fool that test.