GalvanizedHero

Disclaimer: sticky says cat delete threads are ok and directs you to rules, rules say cat delete threads are not ok. Which is it?

The honeycomb sounds like a bag rocks in a washing machine. There are no emissions here in Florida and I've heard a lot of the $50 jobs on eBay are going to end up throwing a code anyway. I have no intention of putting a $150 cat on a $1300 jeep.

I'd like to hear from people who have done a cat delete about their experience with droning, mileage, throttle responsiveness or general gains/losses if any.

Please don't respond with "you'll lose 50 hp and 10mpg because some guy told me so" without the links to the dyno runs that the guy who told you so performed.

dave1123

I'm not touching this one.....

tech

Being you have a 96 XJ that is a OBD2 system and it does check if the cat is working , so you will get code for the cat not working . that"s about all I will say about this .

GalvanizedHero

To what degree I wonder. In my f150 if there's a pinhole sized breach before the downstream sensor it'll throw a code. This cat sounds like there's nothing left in there but mush and yet I'm not getting any codes.

00t444e

I don't have a cat on my 97 XJ or my 98 Dakota and neither one throws a code because of it. Removing the cat won't drop your fuel mileage any because the O2 sensor that is used for engine performance is before the cat, it will free up the exhaust some but as long as you still have a muffler it won't be much louder.

GalvanizedHero

Thanks for this. When you search cat delete videos it's always guys who just straight pipe it all the way out the back and it sounds just horrible to me.

Cummins93

I have a 96 sport turbo 4.0L with a gutted cat. It eventually threw a cat efficiency code. I put in an o2 spacer and have run it that way for a while with no codes.

s346k

PatHenry

I think it's technically illegal under federal law to have an on-road vehicle without a cat if it originally had one. That said, if your state doesn't test emissions the general check for the cat is visual (if at all), so in theory (though I'm not suggesting or advocating it) if the cat was "gutted" it would hard to accuse someone of violating the federal law.

Cummins93

Oh yea I put a legit cat on every time I hit the road. Just clip it on and go.

GalvanizedHero

I wouldn't be against busting the broken bits out and slapping it back on there if it made the job any easier but In all the videos I've seen, people with more patience then myself haven't been able to beat the cat free of the indentations made by the ubolts.

PatHenry

Again, I'm not suggesting you do it or would ever advocate it, but I could totally imagine someone in your situation might consider just cutting the existing cat at the seam on the inside, gutting it and then welding it back together if they were trying to be sneaky.

Someone in a position such as yourself that was willing to flout federal law (I obviously am not willing to break any law, of course) might check with their local state inspection shop and see if putting a straight pipe on would be something that would cause a failure. I know it's hard to believe, but there are shops out there that might not even notice a missing cat since it's under the vehicle and they're busy with customers waiting.

Cummins93

I cut the top of my cat open like a clam shell and took the 2 bricks out whole then bent it back and welded shut.

GalvanizedHero

That's not a bad idea. Any codes?

Garrett S.

I have a 96 and it rattled too. I ran with it gutted for a while and eventually replaced it with a pipe with a port for the sensor. The pipe sounds much better than the gutted cat. I don't normally get a light but I have noticed in the winter if i'm wheeling in the snow in 4wd and really burning a lot of gas in a short time the light comes on. It usually goes away after a day or two of highway driving though.