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Unread 03-29-2009, 07:25 AM   #1
jlarsen2
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Straight pipes on 4.0

I just put a straight pipe on my jeep and was wondering what the excessive gas smell could be when i pull it into my garage. What could be the cause???
It smell richer than when i had the aftermarket exhaust on it.

And is this a bad thing or a good thing?

btw it sounds awesome for a I-6

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Unread 03-29-2009, 08:02 AM   #2
jeep95xj
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its sounds terrible i did it on mine and hated it. do you have a cat? if not thats the answer to your gas smell. also you just cut your gas mileage is half. your motor is dumping a lot more fyel with no back pressure. your plugs and ot sensor wont last long either
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Unread 03-30-2009, 10:07 PM   #3
jlarsen2
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yeah i have a cat but i have not nopticed a severe drop in gas mileage...it was already bad pushin around 13 mpg
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Unread 03-30-2009, 10:15 PM   #4
4.7stroker
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Put a muffler on that rig, it needs some back pressure to operate properly.
I know you want the whole world to hear you driving down the street but honestly you are not going to impress anyone with a rig that sounds like azz.

Dwayne
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Unread 03-30-2009, 10:26 PM   #5
sprngrider
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A muffler delete is a little different than a straight pipe or test pipe. With a test pipe, you delete the cat, which is bad. A muffler delete is fine and will not cause any mech. problems, but the noise would be too loud for me.

The smell could come from running a little richer because of less back pressure.
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Unread 03-30-2009, 11:30 PM   #6
bryris
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A muffler delete? Cat delete? Too funny.
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Unread 03-31-2009, 03:38 AM   #7
sprngrider
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Not posting something worthwhile... Too funny.
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Unread 03-31-2009, 04:48 AM   #8
JIBTEXHNKA
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pointless arguments that make me laugh... priceless
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Unread 05-07-2009, 05:25 PM   #9
jlarsen2
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suprisingly it does get better the only down side it that it pops if you punch it in either First or sencond gear. what could that be???
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Unread 05-07-2009, 09:59 PM   #10
jeep95xj
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To much fuel. Very simple solution. If you want more noise and a little more power go with a high flow cat and a good muffler. Your neighbors and local cops will love you for it. A 4.0 is not a performance motor and doesnt sound good with "open headers" and or no muffler.
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Unread 05-07-2009, 10:14 PM   #11
sprowley
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Quote:
Originally Posted by 4.7stroker View Post
Put a muffler on that rig, it needs some back pressure to operate properly.
I know you want the whole world to hear you driving down the street but honestly you are not going to impress anyone with a rig that sounds like azz.

Dwayne
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Unread 10-03-2012, 06:30 PM   #12
87manche17
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Would it sound like crap on a 87 jeep Comanche, I thought about because it has a lope at idle. I always thought it would sound good to cut the muffler and leave the cat.
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Unread 10-03-2012, 06:42 PM   #13
mrdeath2000
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the CAT does provide some back pressure and muffling. Not sure how much on a Jeep, but on an 06 mustang GT I ran no mufflers for the whole 2 years, perfectly fine, sounds good, not obsurd. removing the cat or running a Hi-flow cat will make it stupidly obsurd and you should be shot.

When I switched my 2.5L to a new header, I had a 4" gap I needed branched between the downpipe and the cat -> muffler, sounded like a top fuel lawn mower.
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Unread 10-03-2012, 07:21 PM   #14
UltimatE
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Quote:
Originally Posted by mrdeath2000 View Post
the CAT does provide some back pressure and muffling. Not sure how much on a Jeep, but on an 06 mustang GT I ran no mufflers for the whole 2 years, perfectly fine, sounds good, not obsurd. removing the cat or running a Hi-flow cat will make it stupidly obsurd and you should be shot.

When I switched my 2.5L to a new header, I had a 4" gap I needed branched between the downpipe and the cat -> muffler, sounded like a top fuel lawn mower.
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Unread 10-04-2012, 07:32 PM   #15
87manche17
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Quote:
Originally Posted by mrdeath2000 View Post
the CAT does provide some back pressure and muffling. Not sure how much on a Jeep, but on an 06 mustang GT I ran no mufflers for the whole 2 years, perfectly fine, sounds good, not obsurd. removing the cat or running a Hi-flow cat will make it stupidly obsurd and you should be shot.

When I switched my 2.5L to a new header, I had a 4" gap I needed branched between the downpipe and the cat -> muffler, sounded like a top fuel lawn mower.
Im running a 4.0, not a 2.5. So i think it would sound better than that.
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