Hey everybody. Here is the deal, the cat in my car has been making very loud growling noises for the past year, and now its gotten to the point that the cat makes this sound no matter whats happening. Not only is it rather annoying, but I equate the cat to my +10 second 0-60 times. Now, considering it has to go, what are my options? I don't want to pay 900 bucks for a mercedes cat, and if im changing it out, id like to get a free flowing performance cat. I found some flowmaster cats for like $200, but I don't know how they would fit. So, any suggestions? If possible, id like it to bolt up pretty similar, but I think that the front end of the cat has to be welded (it is on my car anyway) so ill prolly end up taking it to a muffler shop so even if the new cat isn't a perfect fit it shouldn't matter. Thanks for your help!

My cat was making very loud growling noises as well, she was also staying over the water dish without drinkgin, but luckily my best friend is a veterinarian.

I expect that a muffler shop can weld in a high flow "catalytic converter" as long as there is room underneath.

Good luck,

It would be a surprise to me if a cat failure would result in any noises. There are no moving parts in a cat.
Typical symptoms of a cat getting clogged is that the engine sort of 'hits a wall' where it just won't produce any power above a certain RPM.
My first thought would be that it has a loose and noisy heat shield on it. This can make a terrible racket, but it is usually easy to fix.

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1986 300E 5-Speed 240k mi.

im pretty sure its not the bracket, the sound is a loud growling noise, like an air constriction, I had my mechanic check it out, and he said it was the cat (I thought it was a hole in the exhaust)

Interesting symptom. Maybe there are loose broken bits of the medium inside that are rattling about.
Say, what sort of emissions testing do they have in TX?
I was under the impression they were pretty loose about such things.
Perhaps you could 'gut' the cat instead of replacing it?

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1986 300E 5-Speed 240k mi.

hehe.... yea in texas they don't have emissions testing :-) So, what would be the process of gutting the cat? (My friend was going to stick a piece of rebar in his, but he has a 72 pickup, so it doesn't really matter what he is going to do to it)

A slight correction regarding emissions testing in Texas. They DO HAVE emissions testing in; Dallas, Tarrant, Collin and Bexar counties. For registration stickers in those counties there is an identifying mark. As long as you don't have the mark, you get an inspection once per year(the initial inspection of a NEW car is good for two years) with no sniff test. The counties above do a dynamometer based sniff test.

Have a great day,

Well, one more reason not to move to Dallas...
Gotta love TX.
I have gutted a cat once.
It was clogged, and I had nothing to lose.
Amazingly, that particular car did continue to pass emissions, but that was a 1979, and the test is less strict for older models.

I used a big punch chisel to drive out the medium.
It's like a big honeycomb of thin metal, and breaks up easily
Rebar would work.
Of course, it would be more fun to use your concealed pistol.

Gutting is not as easy with a welded-in cat, which I believe is the case here.

You could also replace it with straight pipes.
This would be easier for a DIYer without a welder, since the cat could be cutout, and the new straight pipes could be clamped in its place.

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1986 300E 5-Speed 240k mi.

hmm alright, straight pipes sound good. We shall see, if I get accepted into Stanford next year, I guess ill be putting on a set of uber constictive cats, but I heard freshman can't bring their cars on campus anyway, so I guess this would be a 2 year solution...

California would not be amused in the least...
by the straight pipes, or the pistol...

This potential move favors the clamps as a temporary, and easily reversible solution. If you move to CA, you can simply clamp in a new cat instead...

My sister kept her TX registration for many years after leaving the state, knowing full well her car would not pass inspection at her various college stints in WI, MA, or NY.

We should all be TX residents-in-exile, like Prez. Bush Sr.

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1986 300E 5-Speed 240k mi.

hehehe.... yea, now that would be great, but I need some advice, if im going to be punching holes in my cat with a gun, id like to use something with a little punch, how bout a desert eagle...anyone know where on earth I could hide one of those?

ALL counties in Texas require emission testing to have your car inspected. In fact, as of May 1st, more stringent testing was put in place statewide per legislative enactment.

Travis county, being the most environmentally sensitive county in Texas may have gone even further in emissions testing.

Would love to know who told you that there are no emissions testing in Travis county where you reside.

~Paul

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'91 300E, 214K miles

Oh sure. Burst my Texas bubble...
Next you guys will pay income tax and have your guns confiscated.
Now where can I dream of living free from over-reaching regulations? I wonder what the laws are in Montana...

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1986 300E 5-Speed 240k mi.

are you sure about the emissions inspection? I got mine done less than a month ago, they took my car, drove it around the gas station parking lot, slammed on the brakes, accelerated hard, turned the lights and the turning signals on, checked the brake lights, attempted to take off the old sticker and stuck the new one next to the residue from the old one. Said thankyou verymuch and handed me the keys....

Audrey:

You're correct. Emissions are only tested in 6 TX counties, while all others get an "emission component inpection including gas cap."

I'd imagine this would include the cat, but these inspection guys are so stupid they probably have no clue where it is.

Good luck!

~Paul

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'91 300E, 214K miles