2.25, or 2.5?
#1
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Year: 1993
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2.25, or 2.5?
hey guys, im looking at getting an exhaust for my xj. right now its all stock, its a 93 country with the h.o. and the 5 speed, and 73,000 miles. from what i have seen and heard, i like flowmaster super 44's. I live in Wyoming (no emissions inspection) and im not gonna have a cat on my exhaust system, just muffler. now my question is, should i go with a 2.25 inch exhaust, or 2.5 inch? and while im talking about it, does exhaust on these give any seat-of-the-pants performance? and how much of a difference does it make getting a high flow intake (k&n or such)??? thanks for any info
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#3
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Anything larger than 2.5" and your going to loose your mid range torque.
Without a cat, I would think that 2.25 would be good.
Check the Jeep Speed Racer project and see what they used.
http://www.jpmagazine.com/projectbui...eed/index.html
Without a cat, I would think that 2.25 would be good.
Check the Jeep Speed Racer project and see what they used.
http://www.jpmagazine.com/projectbui...eed/index.html
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you need to read the stickys and take the comment out of your post, and you might get answers. i would go with the 2.25. And a true cold air intake will give you added performance, not just a tube and filter but the cold air sheild.
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I just love sitting in traffic behind a car with no cat. That's just great. You know, a car without a cat puts out as much pollution as like 50 identical cars that have their cats installed. Just put a hi-flow cat on there and be kind to your environment.
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Year: 1989
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The inlet of the stock cat is 2.5" and goes to 2.25" So if you are going for full new exhause, pick up a universal 2.5" cat, muffler of your choice (I prefer Magnaflow/bullet performance and aero turbine) and turn down or pipe as far back as you want to go.
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OP, keep your cat or get a high flow.
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You guys are all enviromental? Yet off-road and cause errosion, and stroke out your engines.
No emissions so no worries of a cat. A LOT of people go with ot. Tractors go without it, lawn equipment go without it.
I used to have a 240z and not even federal law required me to have a cat. Get over it. Diesels are on the road, so WTF. No one will reply if you don't have a cat?
Even in areas that have emissions, people will put their cat exhaust just for emissions or put a fake one on.
Get over it. Sry, but seriously. And hypocritical.
I'd go 2.25 myself. Even on a stroker and without a cat. I'd go catless in a heart beat but I live in an emissions county. And yes, I do recycle. Seriously.
Oh, btw, it isnt like running without a cat is like having the exhaust of 50 cars. It is more like 3 to 5 tops. My friend has an Eclipse without a cat and somehow passed emissions testing. He has a 3.0L v6 200hp SOHC, and I have a 2.8L v6 125hp OHV. His emissions were only 4 times worse than mine, but was still within legal limits so passed caused they thought he had a cat.
If the exhaust came out of 50 cars, this guy would have been WAY over legal emission limits without a cat.
No emissions so no worries of a cat. A LOT of people go with ot. Tractors go without it, lawn equipment go without it.
I used to have a 240z and not even federal law required me to have a cat. Get over it. Diesels are on the road, so WTF. No one will reply if you don't have a cat?
Even in areas that have emissions, people will put their cat exhaust just for emissions or put a fake one on.
Get over it. Sry, but seriously. And hypocritical.
I'd go 2.25 myself. Even on a stroker and without a cat. I'd go catless in a heart beat but I live in an emissions county. And yes, I do recycle. Seriously.
Oh, btw, it isnt like running without a cat is like having the exhaust of 50 cars. It is more like 3 to 5 tops. My friend has an Eclipse without a cat and somehow passed emissions testing. He has a 3.0L v6 200hp SOHC, and I have a 2.8L v6 125hp OHV. His emissions were only 4 times worse than mine, but was still within legal limits so passed caused they thought he had a cat.
If the exhaust came out of 50 cars, this guy would have been WAY over legal emission limits without a cat.
Last edited by red_dog007; 09-12-2010 at 01:41 AM.
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you say you hate being behind a vehicle without a cat: what about a diesel that blows so much black smoke through an intersection that you cant see? or putting a lift and 35 inch tires on a cherokee? mine is stock and i get 22-25 miles per gallon, what would it get after a 4 inch lift and 35's? it wouldn't improve, that's for sure. im not saying that lifts are bad and not to do them, i plan on one, all im saying is that before people start preaching to me about being environmentally friendly, get some perspective. so you have a cat on your jeep that gets 12-14 miles per gallon, and i don't have one on mine that gets 22-25 mpg....anyway, completely off subject. I figured on the 2.25 inch anyway, and after the responses, i think that's what ill go for. thanks for all your info
#12
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you say you hate being behind a vehicle without a cat: what about a diesel that blows so much black smoke through an intersection that you cant see? or putting a lift and 35 inch tires on a cherokee? mine is stock and i get 22-25 miles per gallon, what would it get after a 4 inch lift and 35's? it wouldn't improve, that's for sure. im not saying that lifts are bad and not to do them, i plan on one, all im saying is that before people start preaching to me about being environmentally friendly, get some perspective. so you have a cat on your jeep that gets 12-14 miles per gallon, and i don't have one on mine that gets 22-25 mpg....anyway, completely off subject. I figured on the 2.25 inch anyway, and after the responses, i think that's what ill go for. thanks for all your info
#13
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Alright, you don't care about your environment. That's fine. How about this, you care about performance right??...Well, the Jeep 4.0l inline six is a torque monster. We all know that. But it requires a certain amount of back pressure from the exhaust system to maintain that awesome amount of torque. If you remove the cat, you will be removing a percentage of this back pressure and therefore will be robbing yourself of some mid range torque. So....Maybe you should think about installing a hi-flow CAT to actually improve performance and as a bi-product you can just happen to be kinder to your environment. :P
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im confused about the whole back pressure thing? I had my entire exhaust off except the headers bacause i was in the process of editing some things, and drove it like that for a week. It road great. not better not worse just the same. Even when you hit or let off the gas quickly the trans never jerked from loss of pressure. i dont think our jeeps need back pressure. i believe its just a giant scam to get people to spend money on these expensive perfomance parts. Think about it. How can a cat be high flow but not loose this supposible needed pressure? its not scientifically possible unless they had a check valve in them. I have put 35000(158000 on odom) miles on my cherokee with my nonbackpressure exhaust and its as strong as ever.
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