i am wondering if changing the full exhaust system is going to give me more of a advantige over deleting the cat and adding a free flow muffler. i read some where that a after market 4" exhaust will only lower egt's about a 100 degrees. seems to me that you could accomplish that by doing the cat and muffler. reason being you can't change from the turbo. (atleast that's what i understand). give me some opinions.

:help: come on guys shoot me some opinions

I changed my exhaust to a 4" one, killed the kat, free flow muff, I don't have gauges so I can't see how much lower the EGT is but I know it's lower and the back pressure isn't as much ;)

Lot's of info available... Search and read; son, search and read! :D .

Exhaust system components, starting from the actual turbo back, include:

1. down pipe
2. front pipe
3. intermediate pipe
4. muffler
5. tail pipe

The OEM front pipe contains the cat. Be careful, many refer to the front pipe as the "down pipe."

In addition to the other components, supporting vendor TTS makes a down pipe. Pictures of components here:

http://www.ttspowersystems.com/exhaust_gmdiesel.htm

Some systems have two piece intermediate or tail pipes. Replacement of the OEM system with a cat-back system (retains OEM down pipe and front pipe w / cat) will reduce EGTs 100 - 150 degrees). Replacement of the OEM system with a "full" system (a cat-back system and replacement front pipe) will reduce EGTs 150 - 200 degrees.

Hope this helps. :)

Got14U- If you can get rid of the cat and install a replacement muffler for cheaper than buying an entire kit, go for it. Most have found it to be cheaper to just buy a kit than to hack up the stocker.

Got14U- If you can get rid of the cat and install a replacement muffler for cheaper than buying an entire kit, go for it. Most have found it to be cheaper to just buy a kit than to hack up the stocker.
that's what i was curious about. thanks

I got rid of the muffler and straight piped it for $65. Just picked up a 1 year old MBRP front pipe on here for $75, intalled this weekend myself. Huge difference in sound and power. Not bad for $140.

One thing you will want to keep in mind is that it is against the law to remove the Catalytic Converter from a street driven vehicle. (If it came with one from the factory, it is illegal to remove it). Although most states don't currently test Diesel trucks for emissions, some are beginning to test and those that do test will often look for the CAT if your VIN indicates that the truck had one when originally built.

The law prohibits commecial shops from installing a non-certified used converter, even if you tell them that it is the same one YOU removed from your truck. They are required by law to install a new or certified used converter or they are subject to fines. The fines are $10,000 per occurrence for commecial shops and $2,500 for private individuals for tampering/removing emission controls such as the CAT, if the EPA or DOT want to push the issue. So far I have not heard of any private owner being fined $2,500 but I have heard of comercial shops being fined $10,000 for removing catalytic converters on street driven vehicles. At the very least the state will require you to install a new or certified used converter before your truck will be allowed to pass the emission test, even if the tailpipe emissions are OK. For this reason, I would suggest that if you do remove the CAT, you may want to save all the parts removed so that YOU can re-install them before you have your truck emissions tested.

With that said, I was browsing through the GM Goodwrench web site and found that GM does offer Cat-Back Performance Exhaust Systems for the 2006 2500HD trucks ( (http://www.gmgoodwrench.com/accessoriesjsp/accessorydetail.jsp?make=gmc&model=sierra&year=2006&detail=06_SIE_CAT&sid=8951586494761083)SEE HERE) (http://www.gmgoodwrench.com/accessoriesjsp/accessorydetail.jsp?make=gmc&model=sierra&year=2006&detail=06_SIE_CAT&sid=8951586494761083). After reading this information, I find it difficult for GM to be able to legally justify voiding a truck's warranty simply because the owner installed an aftermarket Cat-Back exhaust system in their truck.

thanks for the info. i think i'll have the fab guys at my buddies shop do the install. not worried about that. and i had already decided to keep the kitty for warranty issues.