exhaust question

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Nov 10, 2004 | 09:13 AM

redneck93375

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Joined: Jul 2004

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exhaust question

after reading through a few posts I just want to know if there will be a benefit to just removing the cat and muffler from the factory exhaust.

I just purchased the predator and wanted to free up some exhaust. However, I just can't afford the exhaust kits with the larger downpipe right now.

Will it be beneficial if I just have them cut out the muffler and cat and run straight pipe with the factory 3 inch exhaust?

Thanks for the help

Nov 10, 2004 | 09:21 AM

jasfaa

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Joined: Jan 2004

Posts: 1,539

Likes: 1

From: Snohomish, Washington

Quote:

Originally Posted by redneck93375

after reading through a few posts I just want to know if there will be a benefit to just removing the cat and muffler from the factory exhaust.

I just purchased the predator and wanted to free up some exhaust. However, I just can't afford the exhaust kits with the larger downpipe right now.

Will it be beneficial if I just have them cut out the muffler and cat and run straight pipe with the factory 3 inch exhaust?

Thanks for the help

IMO, I would not touch the CAT.

Nov 10, 2004 | 10:03 AM

jdadamsjr

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Joined: Oct 2002

Posts: 11,314

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Welcome to FTE, Redneck !!!!
EGGxactly what I did at first...
I did a straight pipe with my X to see if it would do what I wanted....
ran it that way for 6 months ...

Did lower my egt's and free up the exhaust...
sounded super around town and all... but ....
In the LONG "cab" of my X it was too much drone for the long drives over a couple of hours....
in your SD it may be fine since the cab is shorter than mine...

eventually did get a turbo back exhaust installed....

I left the cat in since others have tested and not seen any difference with or without cat....
( it IS a BIG federal fine if you get caught

)

Nov 10, 2004 | 11:40 AM

redneck93375

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Thanks for all the replies. I went to the muffler shop and we took a look at the underbelly of the beast. It didn't take long and I whipped out the discover for a four inch turbo back kit.

I deleted the muffler and just ran straight pipe all the way. Probably will be a bit noisy, but I have a serious sound system to drown out some of the sound. Darn salesmen, they get me every time.

Nov 11, 2004 | 05:17 AM

t_j82

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Joined: May 2003

Posts: 833

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From: NW Montana

Leave the cat! There is virtually no restriction to it. I was told by the field service rep that this system needs some back pressure to operate the variable veins on the turbo so he said to avoid straight piping.

Nov 11, 2004 | 01:07 PM

SBV45

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Joined: Aug 2003

Posts: 4,483

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From: Central Texas

Quote:

t_j82: Leave the cat! There is virtually no restriction to it. I was told by the field service rep that this system needs some back pressure to operate the variable veins on the turbo so he said to avoid straight piping.

There has been some debate on that. I concur with that analysis. The Exhaust Pressure sensor is at the end of a tube that is between the manifold and the turbo. The exhaust pipes and cat is post turbo. Some people say that if you modify the exhaust post turbo it has no effect on the EP sensor. I suspect it does to some degree. The EP, BARO, MAF and MAP all input to the PCM which in turn controls the VGT actuator to move the vanes to direct exhaust onto the turbines. They are inter related.

I would like to see some analysis done to see if there is an effect on the EP sensor if the exhaust is stock and if it is modified.