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Exhaust Diameter

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Old Aug 31, 2010 | 10:42 PM
  #1  
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From: I'm bad, I'm nationwide.
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Engine: 4.0
Default Exhaust Diameter

What is the ideal exhaust diameter for a 4.0l? what about a stroker?

I am snorkeling my intake and Im going to snorkel the exhaust as well. I guess I should first ask it its really necessary? but oh well I'm going to run a stack up the passenger side A pillar. sweet huh? anywho.....There are going to be a few bends to accomplish this so I will probably have to up the diameter to help with the restriction whatcha think???
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Old Sep 1, 2010 | 11:54 AM
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any help? Im guessing 2.5? but with the bends 3 inches?
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Old Sep 1, 2010 | 11:58 AM
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From: Wantage, NJ
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2.75"
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Old Sep 1, 2010 | 02:58 PM
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Originally Posted by Diesel
2.75"
May I ask your reasoning on this my good man?
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Old Sep 1, 2010 | 03:02 PM
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Ive stroked 3 before.

3" is overkill and makes it raspy, 2.75 is the limit for a clearer tone and ideal pressure. If I had one I would go 2.5".
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Old Sep 1, 2010 | 05:02 PM
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I agree. 2.5" is really the optimum way to go, and like Diesel said, 2.75" with a stroker. Both 4.0's and strokers need that backpressure for low-end torque. A friend of mine once did 3" like you mentioned. Not only did his Jeep sound terrible, it never really ran as strong as it did before.
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Old Sep 1, 2010 | 05:19 PM
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2 3/4", hum, you're playing with us, right?
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Old Sep 1, 2010 | 06:36 PM
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2 3/4 is nuts... 2.5in MAX... 2in is perfectly fine for even mild built 4.0's... i ran 2.5 on mine with injectors, 99+ intake, intake, and header... it ran great with great power... do 2.5 so if you upgrade later your already set... 2.5 is hard as crap to get to fit in some areas... 2 3/4... no... not worth it... dont see it fitting in some places...
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Old Sep 1, 2010 | 08:25 PM
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fit will be an issue anyway so I'm not worried about whats easy. Just worried that in about 4 feet of pipe I estimate over 360 degrees of tight bends. Was worried I'd have to open it up a bit to make the difference. How you guys think that applies? Stick with 2.5 or what?
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Old Sep 2, 2010 | 03:18 AM
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yes 2.5...
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Old Sep 2, 2010 | 07:38 AM
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2.5 is ideal for tone and proper pressure.

2.75 will give a deeper tone, but mind you this is no 8 cylinder, it will be raspy.
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Old Sep 2, 2010 | 07:53 AM
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2.75" exhaust pipe.....does it even exist? Don't see any in the hi-po catalogs, don't see any muffs with 2.75" in/out. Again, you're playin' with us, right?
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Old Sep 2, 2010 | 07:59 AM
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Originally Posted by djb383
2.75" exhaust pipe.....does it even exist? Don't see any in the hi-po catalogs, don't see any muffs with 2.75" in/out. Again, you're playin' with us, right?

No company makes one, I have one on my lifted cherokee. Got it made from Dan the Muffler Man in Newton, NJ. Any welding shop could bend the pipe for you if specs are given. Again, 2.75 is recommended for the strokers. But everyone has 2.5 or 3 cause they only want to buy whats readily available.
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Old Sep 2, 2010 | 08:35 AM
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thank you!!!! 2.5 it is! I gots no stroker just injectors and a 99+ intake
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