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Old 11-27-2009, 11:21 PM   #1
DRobb's_85
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who runs cats on their trucks

Here in Texas, my 85 still requires the visual inspection for cats. The two that are on it are getting old and are probably clogged. I'd like to get rid of them altogether, but I know that its against the law and I wouldnt pass inspection. Has anyone ever "gutted" their cats, where you ram all the junk out of them and weld a pipe through them? I'm thinking about doing this, as I dont really want to drop some money on new highflows, and I'd like it a bit louder anyway..I cant find a shop that will do this though, at least in the city, I dont blame them. So..who here runs cats or "gutted' cats on their trucks, and how did you do it?
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Old 11-28-2009, 12:07 AM   #2
staggerd86c-10
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Re: who runs cats on their trucks

i guess im lucky that here in south florida they dont inspect cars anymore so i just checked them when i got the truck, but gutting them sounds like a good idea, im sure if you talk cash money to one of those shops they can help you out, just make sure you tell them you dont even need a reciept or anything.
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Old 11-28-2009, 12:24 AM   #3
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Re: who runs cats on their trucks

gutting works but you might fail the emmisions test due to high nox readings
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Old 11-28-2009, 02:00 AM   #4
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Re: who runs cats on their trucks

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Originally Posted by staggerd86c-10 View Post
.... im sure if you talk cash money to one of those shops they can help you out.....
What he is requesting them to do is breaking an emmission law. This is a federal offense that carries up to a $50000.00 fine. I don't think you are going to get an shop to take that chance.

I suggest you spend the bucks for high flow cats.
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Old 11-28-2009, 02:07 AM   #5
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Re: who runs cats on their trucks

extremely illegal here in CA. we cant even purchase our own cat-backs online anymore. gotta take it to a shop or dealership to get a new cat installed. I knew a guy that had a mid-90's 4x4. he split the cats in half, welded in a straight pipe, and welded them back together. sounded mean. he had two sets. fake straight-pipes and an actual working cat-back. when he got pulled over by the CHP he would pass a visual. then he would put the real cats on a week before his emmisions test to prep the computer
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Old 11-28-2009, 02:08 AM   #6
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Re: who runs cats on their trucks

here in az the dont even lood under my truck for cats, i still have to emission but its a joke

Last edited by tecky11; 11-28-2009 at 02:09 AM.
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Old 11-28-2009, 02:14 AM   #7
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Re: who runs cats on their trucks

I actually passed CA emmisions sniffer test about 8 years ago with no cats. I had a '76 half-ton that was all stock and never came with cats. It had true dual exhaust too
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Old 11-28-2009, 02:56 AM   #8
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Re: who runs cats on their trucks

The law here in Texas states that any vehicle made in 1984 and beyond that originally had catalytic converters from the factory, must have them present for inspection.

Another Texas law states that vehicles 25 years and older don't get tailpipe tested or emissions tested, only safety inspected. At this time, 84 and up would be exempt, and next year 85 and up will be.

Of course this was a couple of years ago the last time I checked this stuff out, so do some research on the DPS website before you do anything with your exhaust.

The way I interpret these laws is that 84 and up vehicle that are 25 years old at the time of inspection, the catalytic converter must physically be there, but the contents of it...well...
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Old 11-28-2009, 03:01 AM   #9
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Re: who runs cats on their trucks

I have 2 on mine being a 1978 and you didnt
need to have them on cars that are 1977 and under
both my cats are different so im told it might not be running
the way it should.
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Old 11-28-2009, 11:58 AM   #10
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Re: who runs cats on their trucks

My 87 has a "Hearthrob" dual 2 1/4 inch system , I live in Pa. with a visual emission inspection. I used 2 Mustang GT bullet style Cat's worked great , same diameter as the pipes.

Actually made my Flowmaster 40's quiet enough where I could stand it at highway speeds.
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Old 11-28-2009, 01:31 PM   #11
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Re: who runs cats on their trucks

A shop in town told me if it comins in without a cat he cant force the cust to put one back on
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Old 11-28-2009, 04:29 PM   #12
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Re: who runs cats on their trucks

OH NO! Everybody's so afraid of the law!!!! Big fines!!!! I cut my cat out, don't be scared.
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Old 11-28-2009, 09:58 PM   #13
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Re: who runs cats on their trucks

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Originally Posted by oats84 View Post
A shop in town told me if it comins in without a cat he cant force the cust to put one back on
Same here i went to a shop and asked him how much to cut them off and he said he couldnt it was against the law!then after he told me that he said if you come in with no cats then i dont need to put any I thought it was kind of stupid!
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Old 11-28-2009, 10:21 PM   #14
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Re: who runs cats on their trucks

Don't you have any friends with a mig, just ask a muffler shop if they have any short pieces of pipe and do it your self. Its the same deal with my 85 it just needs to look legal.
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Old 11-28-2009, 10:46 PM   #15
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Re: who runs cats on their trucks

get some "thunderbolt" cats off ebay...they make all sizes.

my buddy got a 3" in 3" out, its a high flow cat, very small in size

and a low price at $45 a pop.

DO NOT GET A FLOWMASTER FLOWMONSTER cat !!!! flow and that cat do not belong in the same sentence.
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Old 11-28-2009, 11:29 PM   #16
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Re: who runs cats on their trucks

I'm running dual cats on my '78. Just have a muffler shop fabricate a pair of catalytic "test" pipes for your truck. Nothing illegal about that.
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Old 11-28-2009, 11:57 PM   #17
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Re: who runs cats on their trucks

I plan on running a cat later on

Still open header'd at the moment
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Old 11-29-2009, 12:09 AM   #18
DRobb's_85
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Re: who runs cats on their trucks

Well, as much as I would hate breaking the law , I might just find a way to get this done. This truck doesnt get driven daily, and I want it a bit louder anyways. I dont have access to a welder, so a muffler shop is my only choice. Just finding one will be the problem. And to the guys saying I could just cut them off and take it to a shop that will put straight pipe in their place, I still need the cats on it to pass the visual inspection. 78 Big 10, what do you mean by "test pipes"?
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Old 11-29-2009, 01:30 AM   #19
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Re: who runs cats on their trucks

i think what he means by "test" pipes is to have them make a set to make sure they will work and then "accidently" cut off your cat with a sawzall and have them install the pipes
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Old 11-29-2009, 09:44 AM   #20
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Re: who runs cats on their trucks

I`ll gonna cut mine off of my 88, I know the sticker guys, they don`t look anyway.
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Old 11-29-2009, 10:53 AM   #21
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Re: who runs cats on their trucks

The cat on my 90 Z71 actually gutted itself. It was blowing chunks of the honeycomb down stream and clogging up the muffler. I left the self gutted cat in place after "helping" it finish the job so it didn't damage the new muffler.

I couldn't get it to pass emissions testing without it so I ended up with a Walker high flow universal cat. I didn't notice any power loss but it did quiet it down a little and it passed the chassis dyno / tailpipe emissions test.
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Old 11-29-2009, 03:33 PM   #22
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Re: who runs cats on their trucks

When the OEM "pancake" cat on my 83 was changed out for a MagnFlow 3" High Flow cat man what a wakeup call!!! the truck ran like it was New, those pellet cats are so restrictive
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Old 11-29-2009, 04:44 PM   #23
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Re: who runs cats on their trucks

had several gutted at our local exhaust shop. No problems, runs great, only have visual here too.

Gutting them is fine but on my monte carlo the thumping cam let the sound bounce around in the cats kinda takeing away from the choppy idle. So I too considered running a pipe thru it.
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Old 11-29-2009, 05:16 PM   #24
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Re: who runs cats on their trucks

I don't know about other areas, but here in CA bay area, cats are getting cut off in the wee-hours of the night and stolen. I guess there is some precious metals inside. some people are FORCED to replace their cats
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Old 11-30-2009, 12:31 PM   #25
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Re: who runs cats on their trucks

Its platinum. Cats are selling for about $30 a piece. The price of platinum is way down right now because the auto industry is in the crapper. With the newer high flow cats, you are only going to loose about 5 hp. I don't think it is that big of a deal to run one or two.
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