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cut off exhaust pipe after muffler?


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#1 bonzai272

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Posted 09 February 2007 - 02:25 PM

Ive seen many trucks around town dump the exhaust down after the muffler instead of running a pipe over the axle and out the back or side like stock. What is the purpose of this? I cant remember the kind of muffler is on my '79 GMC 6cylinder but its either a dynomax or magnaflow. I have a nice tailpipe that goes over the axle and exits behind the drivers side wheel. It doesnt sound loud at all, just purrs like a kitten. Some co-workers are saying I should cut that extra pipe off just after the muffler.

Is this to make it sound louder or something as they say? Would this affect smog?

#2 shorepatrol2

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Posted 09 February 2007 - 04:00 PM

Ive seen many trucks around town dump the exhaust down after the muffler instead of running a pipe over the axle and out the back or side like stock. What is the purpose of this? I cant remember the kind of muffler is on my '79 GMC 6cylinder but its either a dynomax or magnaflow. I have a nice tailpipe that goes over the axle and exits behind the drivers side wheel. It doesnt sound loud at all, just purrs like a kitten. Some co-workers are saying I should cut that extra pipe off just after the muffler.

Is this to make it sound louder or something as they say? Would this affect smog?

It's alot more expensive to run the exhaust all the way out the back. They probably just didn't want to spend the extra money

#3 bonzai272

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Posted 09 February 2007 - 04:23 PM

Ive seen many trucks around town dump the exhaust down after the muffler instead of running a pipe over the axle and out the back or side like stock. What is the purpose of this? I cant remember the kind of muffler is on my '79 GMC 6cylinder but its either a dynomax or magnaflow. I have a nice tailpipe that goes over the axle and exits behind the drivers side wheel. It doesnt sound loud at all, just purrs like a kitten. Some co-workers are saying I should cut that extra pipe off just after the muffler.

Is this to make it sound louder or something as they say? Would this affect smog?

It's alot more expensive to run the exhaust all the way out the back. They probably just didn't want to spend the extra money


That makes sense because of all the pipe bending and hangar and stuff. I thought it would make the exhaust sound louder.

#4 Silverado4x4

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Posted 11 February 2007 - 10:34 PM

Not really a smart thing to do, tail pipes out the back get rid of the fumes from the motor, now with todays trucks with fresh air coming through the trucks cab and heating and a/c system the fumes will come out from the sides and up under the truck due to no tail pipe and into your cab so your getting gased from the motor exhaust and might not even know it. But most likely when you sitting there at idle.

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#5 Truckin2007

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Posted 12 February 2007 - 03:21 PM

Not really a smart thing to do, tail pipes out the back get rid of the fumes from the motor, now with todays trucks with fresh air coming through the trucks cab and heating and a/c system the fumes will come out from the sides and up under the truck due to no tail pipe and into your cab so your getting gased from the motor exhaust and might not even know it. But most likely when you sitting there at idle.



some exhaust shops wont dump them out under the cab anymore for that exact reason...could cause poisoning...

i would say some people also dont want them to run out the back for astetic reasons...also ive seen paint discoloration from where tailpipes run out behind the rear tire and then im guessing from the heat and fumes has discolored the paint on the bottom of the bad above tailpipe
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#6 Schmids5.3

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Posted 13 February 2007 - 10:49 PM

Would this affect smog?


No