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post #1 of 7 Old 08-03-2010, 01:40 PM Thread Starter
andrew c
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exhaust back pressure

i recently bough an 07 2 door jk and decided to drop the muffler to see what it sounded like...supprizingly its not very loud, and its deep. however, i didnt notice the torque seemed flat under 2000rpm. the cats are still on, so i figured there would be enough back pressure. has anyone else noticed this? i like a deep sounding jeep..who doesnt, but at the cost of performance im not sure its worth it. opinions?

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post #2 of 7 Old 08-03-2010, 01:54 PM
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Without a muffler you'll lose backpressure which will affect your low-end torque. Taking off the muffler is a trade-off to acheive more open flow at higher RPMs where backpressure would start to work against your engine. If you want the deep sound you are probably better off going with an aftermarket muffler that will still provide some backpressure so you have the low end torque for off-roading.
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post #3 of 7 Old 08-03-2010, 01:57 PM
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an aftermarket "catback" system is the best compromise of back pressure for max torque though often at a compromise of sound inside and out, ...the stock exhaust seems fine and mufflers don't wear out w/ unleaded fuel use much anymore, perhaps the stock exhaust with a similar fitting aftermarket muffler might gain something but, I like the quiet now in my life and the ability to listen to the radio at a low volume. The new JK's do just that!

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post #4 of 7 Old 08-03-2010, 04:15 PM
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A well know phenomenon in racing and motorcycles - open pipes (called drag pipes) are loud and help high end rpms and power, but really hurt at the low end. I second a cat back system if you don't like the stock sound.

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post #5 of 7 Old 08-03-2010, 05:45 PM
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I have an MBRP muffler relocate catback system and it sounds great.
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post #6 of 7 Old 08-04-2010, 12:26 AM
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Whats a cat back system compaired to a bolt on muffler?
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post #7 of 7 Old 08-04-2010, 07:31 AM
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Originally Posted by Rescue13 View Post
Whats a cat back system compaired to a bolt on muffler?
It replaces the exhaust from the catalytic converters back...i.e. cat back. The one I got is stainless steal and the muffler is now under the truck and the tail pipe does not stick out. That will avoid the smashed tail pipe. Also, our stock exhaust pipes are slightly restricted where they are bend. On a good catback system the pipes will be bend so that the pipe is the same diameter at the bends as the rest of the pipe.
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exhaust , JK Wrangler , low end torque , system , Torque , wrangler

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