2.5 inch exhaust= lose torque?
06-22-2010, 09:35 AM
#31
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Year: 1999
Model: Cherokee
Engine: 4.0 i6
my 89 with a 3" lift and 31x10.50 BFG's still gets 18-19 commuting and very close to 25 on trips. the 4.0 really responds to opening up the exhaust. i have done enough to know. if you want to make a difference in torque, go 2.5 from the manifold to the cat, 2.5 from the cat to muffler and use 2.25 for the tailpipe. i prefer to use a flowmaster with center in/offset out. there is not a lot of room under the cherokee so its limited to the 50-series as far as size goes. i have a 40-series on mine and sounds good.
zedpapa
zedpapa
06-22-2010, 11:29 AM
#32
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Year: 1999
Model: Cherokee (XJ)
Engine: 4.0 I6
i wish i could get that kind of mileage on mine. i only have 31s and 3.55 gears with my auto and hte gas mileage dropped alot. i don't have any armor or roof racks and i have stock bumpers. my jeep is stock, minus the lift and the 31s. yes, the jeep is a box but its not geared or even designed for gas mileage. its designed for 4x4 and being the best suv back in its time, which is when gas mileage was not on people's minds.
06-22-2010, 12:21 PM
#33
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Year: 1989
Model: Cherokee
Engine: 2002 WJ 4.0
zeep99xj, mine sounds good for what it is, nice and throaty but not too loud or obnoxious. the setup you said is what is on mine at the moment, but i have plans to switch to a modified HO manifold and go 2.5 manifold-to-cat-to-muffler and use a 2.25 tailpipe. keep in mind that as the exhaust gets further from the engine it cools. when it cools, it contracts and needs a smaller pipe to help maintain velocity. that is why it is suggested to use one size smaller on the tailpipe.
zedpapa
zedpapa
06-22-2010, 01:22 PM
#34
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Year: 1997
Model: Cherokee
Engine: I6
This thread got big quick and off topic in some areas. haha. I dumped my exhaust before the axle and dang does it rumble inside and out, i really only wanted it loud out, gonna have to run the pipe out the back. Its hard to get a 3 inch tip back there though since i have really long shackles
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