Author Topic: 2.5 inch exhaust for 2.5l?  (Read 936 times)

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BarneyJeep

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2.5 inch exhaust for 2.5l?
« on: April 05, 2008, 10:14:38 PM »
factory is 2.25 inch for exhaust, i won a magnaflow stainless muffler at a club run. It's 2.5inch in and out. Will upping the tailpipe diameter to 2.5inch hurt my motors "performance"? or is the tailpipe too short to notice and difference? i know that the majority of my back pressure comes from the cat and not the muffler, but i wanted a few opinions on it... thanks...

Jurassic Jeep

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Re: 2.5 inch exhaust for 2.5l?
« Reply #1 on: April 10, 2008, 12:01:31 PM »
We installed a 2.5" 4WD Cat-back system on our 1995 YJ 2.5L.   Install was a piece of cake.  I cut off the muffler right after the cat.  The cat output is actually 2.5", so I just added a little spacer for the material I took off after the cat.  The tail pipe was way too long so I did trim it back so I won't get it hung up on the rocks.   So far so good and I've noticed some performance gains in the fact that I can run in 5th sometimes.   

BTW....  we're running 33" tires with a 5spd. 

Rob the plumber

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Re: 2.5 inch exhaust for 2.5l?
« Reply #2 on: April 10, 2008, 12:54:53 PM »
My stock head pipe is only like 2" or 2 1/8" right off the manifold. I think you would want to keep the size consistent to really see any gains.

Offline 95 Lowbuck

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Re: 2.5 inch exhaust for 2.5l?
« Reply #3 on: April 10, 2008, 05:40:05 PM »
I think it has been talked about before in this forum
that Jeep used the same exaust for both the 2.5L and 4.0L.
If it was good enough for the 6, it should be plenty for the 4.
1995 YJ RioGrand, 2.5, AX5, 231 T.C., A.A. SYE,
D30, XJ D44, Truetracs F+R, CV D.S. F+R, 4.88's
R.E. 4" STD., 33-10.50 BFG KO2's on stock rims.

Offline Bounty Hunter

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Re: 2.5 inch exhaust for 2.5l?
« Reply #4 on: April 10, 2008, 06:15:10 PM »
Stock exhaust is usually 2.25" before the cat and 2.5" after, so you won't notice much difference.

BarneyJeep

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Re: 2.5 inch exhaust for 2.5l?
« Reply #5 on: April 11, 2008, 03:18:29 PM »
awsome thanks!!!