Pre 84 Trucks 1st gen pickups

Does the Cat really matter?

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Old May 14, 2012 | 01:37 PM
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From: Swamp east MO
Does the Cat really matter?

I have a fresh 20/22 hybrid with no smog anything on it, does it really matter if the cat has the guts in it or not?

I would like to do 2 1/4" exhaust on it and was just going to cut the hole in each side of the cat to the size of the tubing used, knock out all the crap and run strait pipe through it. Will it make a difference at all? I need the Cat to be there for inspection purposes. Visual not emissions.

I can unplugg it and nothing changes to the sound or performance of the engine.

Last edited by dirtdobberoffroad; May 14, 2012 at 02:02 PM.
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Old May 14, 2012 | 01:38 PM
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if you gut it, and all you need to pass is the visual. you'll pass.
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Old May 14, 2012 | 02:00 PM
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Yeah Ive done that a few times before but with bad results from emission controlled truck (bad gas mileage). If the truck is not emissions controlled will it make a difference?
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Old May 14, 2012 | 02:15 PM
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Shouldn't make any difference on a carbed truck.
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Old May 14, 2012 | 02:23 PM
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Well I think I will go out an knock all that crap out of my cat thanks.
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Old May 14, 2012 | 05:44 PM
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Well, the O2 sensor is mounted before the catalytic convertor on these vehicles(with OBDI/that have O2 sensors) So, it makes no difference whatsover(engine control wise) if it's gutted, or if it's even there at all. Of course, no pre 84 trucks even have have O2 sensors though. So how it could possibly make a difference(engine control wise) is beyond me...

Last edited by MudHippy; May 14, 2012 at 05:55 PM.
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Old May 14, 2012 | 05:46 PM
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^ Yep, truck has no idea if its there or not.
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Old May 14, 2012 | 06:05 PM
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ive gutted my cats on my 3.0 and 22re.. havent noticed a difference except on my 22re i had really good gas milage with 250k 410s and 34's 300 miles a tank. does anyone no if it affects low end power because of the lack of back pressure? never had a positive answer
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Old May 15, 2012 | 04:21 AM
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Ok I should have stated in the begining that its an '82 and it has an O2 sensor in the back of the cat. I didnt get it gutted last night but I did get it jerked off and decided I was just gonna run 2" thats what the cat inlet is but the out is 1.5-1.75. Some one boogerwelded a smaller tube inside the 2" opening.
The way the cat is made I couldnt knock the stuff out from the back it was like the cat material was laid up and down and not front to back if that makes sense. Most cats Ive seen you can hold them up and see a honey comb and this one you cannot. I will have to cut it open first to knock all the crap out.
I fired it up open header/manifold and my nieghbor thought I put a SBC in it.....I laughed so hard.
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Old May 15, 2012 | 10:18 PM
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Originally Posted by dirtdobberoffroad
I didnt get it gutted last night but I did get it jerked off
uhuh huh huh /Butthead laugh
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Old May 15, 2012 | 10:51 PM
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Hahahahaa..... I needed that. Thanks, Mr. Bond^^^

I liked this, also>>>

Originally Posted by dirtdobberoffroad
Well I think I will go out an knock all that crap out of my cat thanks.
Poor kitty, lol.

PS> SUP DOBBER? Hope s'all good
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Old May 16, 2012 | 04:09 AM
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LOL yeah yeah I say some stupid stuff.........Well I totaly butchered the cat first I was gonna pull the plug out and blow all the little bb's out but that didnt work plug was rusted in, then I thought well I will cut a hole in the top and did that and realized that most of the baffles in the cat was rusted shut so I tried to cut the thing out and by the end I have little pieces of cat spead all over....guess I will cut the flange off of it and replace it with a piece of tube, I hope it will pass.

I cannnot belice how much better it runs with the open header/manifold.....throttle response it great.
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Old May 16, 2012 | 04:13 AM
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From: Swamp east MO
Originally Posted by ChefYota4x4
Hahahahaa..... I needed that. Thanks, Mr. Bond^^^

I liked this, also>>>



Poor kitty, lol.

PS> SUP DOBBER? Hope s'all good

That will be one of those quotes people put in there signature!!!!!!!!


All is good and you?
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Old May 16, 2012 | 06:53 AM
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Originally Posted by MudHippy
Of course, no pre 84 trucks even have have O2 sensors though. So how it could possibly make a difference(engine control wise) is beyond me...
Negative-82 +



Originally Posted by dirtdobberoffroad
Ok I should have asstated in the begining that its an '82 and it has an O2 sensor in the back of the cat.
Also has one on the exhaust manifold, the sensor on the cat may just be a temp probe( on my '81 that is what it does)
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Old May 16, 2012 | 10:01 AM
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Originally Posted by dirtdobberoffroad
And by the end I have little pieces of cat spead all over....
SEE? I KNEW IT, you're a CAT MURDERER! hehehe.

JK, and I'm ok... lil rough right now, but I'll make it

Glad it's running ok... And, I hope you don't have an issue with inspection.
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Old May 16, 2012 | 10:44 AM
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Originally Posted by dropzone
Negative-82 +
I'm unable to confirm that. The earliest oxygen sensor part number for a PU/4Runner that I can find, 89465-19055, Toyota states is for:

Truck, Pickup 1983.08-1987.08 4cyl 2.4L
4Runner 1983.08-1987.08 4cyl 2.4L

And, of course, 1983.08 is 1984 MY.

So how are you able to verify that?

I can understand catalytic convertors, EGR valves, PAIR valves, EVAP systems, and/or other mechanically/vacuum operated emissions systems being used on a carbureted engine. But since a carbureted engine doesn't have an ECU, or any way for it to adjust the amount of fuel flowing to the engine, how is it able to use input from an O2 sensor? It makes absolutely no sense(pardon the pun).

Last edited by MudHippy; May 16, 2012 at 10:48 AM.
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Old May 16, 2012 | 01:48 PM
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From: Swamp east MO
Originally Posted by dropzone
Negative-82 +





Also has one on the exhaust manifold, the sensor on the cat may just be a temp probe( on my '81 that is what it does)

My manifold does not have a sensor but it does have/had one on the cat it had a green plug that went under the seat and ran into the wiring harness on the drivers side......

Wow I think this is my best thread ever, every one is getting involved......

Oh and I didnt kill that cat! CHEF. my grinder did...LOL
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Old May 16, 2012 | 02:38 PM
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Originally Posted by dirtdobberoffroad
lol Yeah yeah i say some stupid stuff.........well i totaly butchered the cat first i was gonna pull the plug out and blow all the little bb's out but that didnt work plug was rusted in, then i thought well i will cut a hole in the top and did that and realized that most of the baffles in the cat was rusted shut so i tried to cut the thing out and [u]by the end i have little pieces of cat spead all over....[/u]guess i will cut the flange off of it and replace it with a piece of tube, i hope it will pass.

I cannnot belice how much better it runs with the open header/manifold.....throttle response it great.
another rob zombie fan...but seriously, do you have inspections on older vehicles in MO, cause I plan on moving out there this summer and I have a diesel conversion? (not to hijack your thread)

Last edited by dewiseman; May 16, 2012 at 02:43 PM.
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Old May 16, 2012 | 04:56 PM
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Does the Cat really matter?
only to the dog!......sorry,it had to be said.
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Old May 16, 2012 | 09:52 PM
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Originally Posted by dirtdobberoffroad
My manifold does not have a sensor but it does have/had one on the cat it had a green plug that went under the seat and ran into the wiring harness on the drivers side......

Wow I think this is my best thread ever, every one is getting involved......

Oh and I didnt kill that cat! CHEF. my grinder did...LOL
hmmm. interesting i am picking up a low mileage engine out of an '82 that has an 'O2 sensor right out of the exhaust manifold..
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