removing muffler?????

jeepin_al · Dec 30, 2004

Ok, I am picking up a 92 4.0 tomorrow and since I live in a state with no emmisions I am thiking of pulling the muffler and running a stright pipe from the cats out to the rear. I am still planning on having the exhaust out the rear but I am going to shorten the pipe a little in order to make sure I don't get hung up and end up with a C wrapped around my axle (had it happen once and it took me 3 hours on the trail to get it untangled). Has anyone done this and how did you like it? I know I won't gain any horsepower but I will admit I like a little engine rumble in my vehicle and this won't be a daily driver but will get driven on the weekends as well as too and from the trails.

BajaXJ92 · Dec 30, 2004

Don't lose the muffler.

The 4.0L likes some backpressure. You'll lose a bit of torque otherwise.

Get yourself a decent cat-back system, like Rusty's Flowmaster, Dynomax, etc.

I run a flowmaster 50 series catback on my stroker, adequate backpressure and like the sound.

MuddinXJ · Dec 30, 2004

i'm running no cat and a almost hollow glasspack and havent noticed any power losses and like the sound.

Rev Den · Dec 31, 2004

Cat and decent muffler, just like Baja said (can't believe I said that) is the way to go.

Rev

ChuckD · Dec 31, 2004

I agree, you loose low-end torque, I have a 93'

XJJPR · Dec 31, 2004

I have it that way but with the pipe all the way out the stock location in the back.

Didn't notice any loss of anything but the dents in all those expensive muffs I use to have!

hinkley

lankchevy · Dec 31, 2004

yup all im running is a cat with strait pipe out to the stock location. i need a new cat tho, mine is beaten in to about half the original size. i didnt notice any loss in power when i did it either.

kolby

90KrawlerXJ · Dec 31, 2004

Ya'll didn't notice anything because the cumulative loss is gradual. Stick with a low restriction muffler: flowmaster, glasspack, etc. The only motor straight pipes ever benefited was a big block with over 450 horses

XJJPR · Dec 31, 2004

90KrawlerXJ said:
Ya'll didn't notice anything because the cumulative loss is gradual.

I don't know about the other guys but I took my muffler off in one fell swoop!

What do you mean by this?

Do you really think the cat doesn't have enough back preasure all by itself?

hinkley

BrettM · Dec 31, 2004

i've got a cat only and it's alright. i wonder about the back-pressure thing though. I think I'm gonna try tack welding a small piece of plate over part of the end of the pipe to increase backpressure. then try tacking it in a different place to allow more or less flow, and see if I can find an ideal.

xjfish · Dec 31, 2004

BrettM said:
i've got a cat only and it's alright. i wonder about the back-pressure thing though. I think I'm gonna try tack welding a small piece of plate over part of the end of the pipe to increase backpressure. then try tacking it in a different place to allow more or less flow, and see if I can find an ideal.

Good Idea. Let us know what you find if you do it. I'm also running just a cat with no tailpipe and i didn't notice a change in power. Doesn't mean its not there though. I plan on getting a muffler and gutting the cat for better sound, but I would rather leave the cat if its backpressure is beneficial...

MJ1990buildup · Dec 31, 2004

you might loose a little on the low end without a cat, but you gain alot more higher in the rpms when the exhaust can flow right out

removing muffler?????

jeepin_al

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BajaXJ92

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MuddinXJ

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Rev Den

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ChuckD

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XJJPR

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lankchevy

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90KrawlerXJ

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XJJPR

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xjfish

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MJ1990buildup

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