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My state does not have emission testing, because it’s stupid. Florida tried it years ago, became a scam business, they did away with it.

I want to improve the mpg of my little 2.5 4 cly, this seems to be the best way. 97 TJ.

Anyone tried it?

Ya, I know, technically illegal in some states, hell, they wont even prosecute those stealing cats With a saws all!
 

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2015 WK2 Overland
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If your cats are functioning properly they are providing little to no restriction. I just tested the ones in my '05 and at 2k RPMs its right around 1psi of back pressure.
 

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Sssh...don't say emissions tests are stupid or you'll have Greta Greentrees joining the forums and protesting.
Had enough of these silly buggers glueing themselves to our roads and drying out the fuel pumps. Spray them with cat piss I say 🤣
 
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2020 WK2 - previous Jeeps:XJ, WK
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That’s the worst argument I’ve heard in long while. It would be a big FU to everyone around you. For a few mpgs that you will actually never see. Oxides of nitrogen are toxic to breathe and to have skin contact with. Maybe you weren’t around in the sixties before catalytic converters started removing these NOX compounds. It wasn’t healthy for humans or forests, crops and even the fish in our rivers. Look up acid rain. It’s illegal to remove the cat for very good reasons, one being your own own health If you at least care about that. I hope you will decide not to remove the cat.
 

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You could end up with not only crappier engine performance but also the CEL light constantly blaring at you.
Modern engines designed with cats are tuned for them based in part on O2 sensor feedback.
 

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My state does not have emission testing, because it’s stupid. Florida tried it years ago, became a scam business, they did away with it.

I want to improve the mpg of my little 2.5 4 cly, this seems to be the best way. 97 TJ.

Anyone tried it?

Ya, I know, technically illegal in some states, hell, they wont even prosecute those stealing cats With a saws all!
Wouldn't bother. If it actually worked, then a lot of manufacturers would've already done it or revamped the cats to help their EPA ratings a long time ago.
 

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2019 TrailHawk
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My state does not have emission testing, because it’s stupid. Florida tried it years ago, became a scam business, they did away with it.

I want to improve the mpg of my little 2.5 4 cly, this seems to be the best way. 97 TJ.

Anyone tried it?

Ya, I know, technically illegal in some states, hell, they wont even prosecute those stealing cats With a saws all!
I replaced my cat with a test pipe and saw exactly zero gains in fuel economy. All it really did was make the exhaust system a little louder and it also made the exhaust stink more, but that's only noticeable when stopped at a red light.
 

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2020 WK2 - previous Jeeps:XJ, WK
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My state does not have emission testing, because it’s stupid. Florida tried it years ago, became a scam business, they did away with it.

I want to improve the mpg of my little 2.5 4 cly, this seems to be the best way. 97 TJ.

Anyone tried it?

Ya, I know, technically illegal in some states, hell, they wont even prosecute those stealing cats With a saws all!

I can see why you were wondering about this but from all the responses you got, I guess it’s clearly not worth the effort.
 

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I replaced my cat with a test pipe and saw exactly zero gains in fuel economy. All it really did was make the exhaust system a little louder and it also made the exhaust stink more, but that's only noticeable when stopped at a red light.
People behind you know. I run across old cars from time to time and you can smell them before you see them. The biggest change I noticed when I came to the US in the mid 80s from the UK was that cities didn't stink of gasoline.
 
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