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Stright Pipe or Cat replacemnt?

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Old 09-12-2015, 10:16 AM
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Default Stright Pipe or Cat replacemnt?

I got a 95 xj. My cat has a hole so im getting it replaced. My dad told me I can just stright pipe it but ik wondering will i have worse gas milalge when i do. I live in Michigan so we have bo inspection laws. Any suggestions?
Old 09-12-2015, 10:30 AM
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It's against Federal law. Taboo to even discuss eliminating or altering them at CF. A replacement is not that much.
Old 09-12-2015, 04:09 PM
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If you're okay with the CEL always being on then you can straight pipe the whole thing. You'll throw your o2 sensors out of whack which in turn will affect your performance and gas mileage. Not recommended.
Old 09-12-2015, 04:32 PM
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While eliminating your cat is against both forum rules and federal law, I'd just like to clarify the previous poster who said it'll throw your O2 sensor readings off and mess with driveability. The upstream O2 sensor gives feedback to the ECU, and that's not affected by the cat being in place or not (assuming it's not clogged, of course). The downstream O2 sensor monitors cat performance and will throw a CEL if you eliminate the cat or it's otherwise not performing correctly.

Again, don't eliminate it.
Old 09-12-2015, 05:03 PM
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How much would you actually gain, powerwise? Because a replacement cat is really cheap. I put a cat on mine, even though being in England and running on LPG I could have got away with a straight pipe. I just couldn't see the point.
Old 09-12-2015, 05:08 PM
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No downstream O2 on a 95 to set a code, but you shouldn't run without a catalytic converter. The power gain isn't real noticeable.
Old 09-12-2015, 05:16 PM
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There will be zero power difference unless the factory cat is plugged.
Old 09-12-2015, 05:35 PM
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See about an aftermarket cat, they're not much money & you'll probably hate driving without a cat. a buddy did (years ago) & his car was almost unbearable to ride in or drive near.


Buy a Cat & toss it in.
Old 09-12-2015, 09:07 PM
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I am in the same boat as the OP, except that my cat was causing a loss of power when driving it especially up hills (paved). This past week one morning before work I cut the cat off, from the end of the up pipe all the way back and it sounds like a tank but my jeep is running much better power wise. I just placed my order on amazon for the head pipe, new O2 sensor, cat, tail pipe, muffler, clamps and hangers for about $260. These were mostly walker pipes and I may have get some welding done to it but it won't be much.
Old 09-12-2015, 09:32 PM
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Originally Posted by cliffy
I am in the same boat as the OP, except that my cat was causing a loss of power when driving it especially up hills (paved). This past week one morning before work I cut the cat off, from the end of the up pipe all the way back and it sounds like a tank but my jeep is running much better power wise. I just placed my order on amazon for the head pipe, new O2 sensor, cat, tail pipe, muffler, clamps and hangers for about $260. These were mostly walker pipes and I may have get some welding done to it but it won't be much.
You don't need to weld the walker parts just get some 2 1/4 inch clamps and it will go together fine.
Old 09-12-2015, 09:52 PM
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I ordered the clamps to go with it but on the previous setup someone welded a pipe onto the cat to extend it for some reason. If I need to do something similar I will but I don't think it will come to that or so I hope. Thanks for the input too.
Old 09-13-2015, 12:43 AM
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Not sure about the Jeep engine operating system, but on some GM cars, the engine runs a bit lean without the converter, so it's best to replace it. I'm a believer in keeping our air clean too !!
Old 09-13-2015, 08:49 AM
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Sell your original cat to a scrapper. Depending on your area, it is worth $30-50 (assuming it is a factory cat).

Then buy a new cat from Performance-curve.com. They have great cats for as low as $60-70, maybe less.

Replace the cat. It is the law, and we'll all have cleaner air to breath when you do.
Old 09-13-2015, 09:58 AM
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Make sure you can take the cat to a scrap yard, most want proof that you replace these for a living since they are a popular item to steal for the metals inside of them. I called my local scrapper and they won't even touch them and found another online that will but I would need a business license to take it there.
Old 09-13-2015, 11:59 AM
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[QUOTE=caronaxtr;3141066]See about an aftermarket cat, they're not much money & you'll probably hate driving without a cat. a buddy did (years ago) & his car was almost unbearable to ride in or drive near.

Why?
Was it that loud?did he have a muffler installed?


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