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hollowing out the 3rd cat

desert

By desert
in Engines & Drivetrain

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Antoine08 Enthusiast

Antoine08

Posted
Posted

i keep going back and fourth about this mod.

Same here. Don't want to end up popping a code or run to lean

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desert
desert

Hoist the truck by the frame to allow the suspension to drop. Remove the clamp from your third cat. Pop the rubber exhaust hangers loose with spray lube and large screwdriver. Pull the entire cat-back

Cliff14Denali
Cliff14Denali

How is this done? Did you have to cut the factory pipe to hollow it out or just unbolt cat back? I haven't really looked at the factory system yet.

Chris
Chris

No it wont. Cali no longer does a sniff test. It is plug in make sure there is no pending codes and pass

Cliff14Denali Enthusiast

Cliff14Denali

Posted
Posted

I did it with no issues....if you have stock cat back or just replaced the muffler only, you won't even notice much of a difference.

  • Like 1
2014MallCrawler Enthusiast

2014MallCrawler

Posted
Posted

I have the full AFE 3" catback. I just wanted to know if I could get a more aggressive tone. Im not worried about lean issues. I have HP tuners and a tuned truck. that's easy to correct. I was more along the lines of it being a waste of time or money for the outcome.

  • 1 month later...
lemmuhj Enthusiast

lemmuhj

Posted
Posted

Would cutting out the resonator be a better option for sound and just leave the third cat?

 

(I replaced stock muffler with a Borla muffler)

SouthernSilveradoGuy85 Senior Enthusiast

SouthernSilveradoGuy85

Posted
Posted (edited)

Would cutting out the resonator be a better option for sound and just leave the third cat?

 

(I replaced stock muffler with a Borla muffler)

 

I had everything from the muffler back taken out and didn't touch any of the 3 cats and the sound is awesome and very aggressive. I have a Flowmaster Super 44 single in/dual out and it's the loudest and best sounding truck I've had. I can listen to XM without needing the volume that high even with the windows down (non Bose) while it's loud enough at idle that I can remote start it from my back yard or back end of the house in my bedroom and hear it just fine (I park on the street in front of the house).

Edited by SouthernSilveradoGuy85
  • 1 month later...
07Softail Senior Enthusiast

07Softail

Posted
Posted (edited)

I just drilled mine out today and it made no difference whatsoever as far as sound goes. Now screwing the flapper-valve open made more of a difference on the idle sound. Resonator delete is next and if that doesn't do it for me i'm going with a Jones Perforated core muff.

 

RT

Edited by 07Softail
  • 1 year later...
chrislim Enthusiast

chrislim

Posted
Posted

just had mine removed yesterday(little background,I've got a 6.2 with a muffler delete and resonator delete). Sounds a little different on start up but not louder, makes more crackles and pops on decel, where you really notice the difference is up high in the rpm range, it sounds a lot more aggresive

bgweed Enthusiast

bgweed

Posted
Posted

017_zpsf28c1668.jpg

 

018_zps7d06d29a.jpg

 

019_zps47dc882c.jpg

 

 

This progression is still a bit unclear to me - how did you manage to get the guts rolled up and pulled out?

just had mine removed yesterday(little background,I've got a 6.2 with a muffler delete and resonator delete). Sounds a little different on start up but not louder, makes more crackles and pops on decel, where you really notice the difference is up high in the rpm range, it sounds a lot more aggresive

 

Did you have the cat gutted or did you have it removed altogether?

chrislim Enthusiast

chrislim

Posted
Posted

 

This progression is still a bit unclear to me - how did you manage to get the guts rolled up and pulled out?

 

 

Did you have the cat gutted or did you have it removed altogether?

I had it removed

 

 

Sent from my iPhone using Tapatalk

DTOMKIDD Enthusiast

DTOMKIDD

Posted
Posted

Will this effect the trucks ability to pass smog In cali? I want to do this but am afraid of having to have a new cat welded in if it fails.

 

Sent from my SAMSUNG-SM-G890A using Tapatalk

carkhz316 Enthusiast

carkhz316

Posted
Posted

I don't know about the rest of you, but here in MN you can scrap Cats and get money. Even a small one like you guys are hacking up is worth $20-30 here. If it were me, I'd just cut it out and turn it in, then section in pipe where you omitted the Cat.

TJay74 Senior Enthusiast

TJay74

Posted
Posted

Will this effect the trucks ability to pass smog In cali? I want to do this but am afraid of having to have a new cat welded in if it fails.

 

Sent from my SAMSUNG-SM-G890A using Tapatalk

 

Yes it will affect the ability to pass the California smog test. The whole reason the GM cars have the 3rd cat is for the California smog test. GM used to make 2 sets of each vehicle, 49 state and California. In the recent years they found it was cheaper to make a 50 state car that meets the strictest emission requirements which is the state of California.

DTOMKIDD Enthusiast

DTOMKIDD

Posted
Posted

 

Yes it will affect the ability to pass the California smog test. The whole reason the GM cars have the 3rd cat is for the California smog test. GM used to make 2 sets of each vehicle, 49 state and California. In the recent years they found it was cheaper to make a 50 state car that meets the strictest emission requirements which is the state of California.

I was pretty sure it would fail just thought I'd check, thanks for the help!

 

Sent from my SAMSUNG-SM-G890A using Tapatalk

bgweed Enthusiast

bgweed

Posted
Posted

I'm having my truck tuned Saturday... I'm wondering if I should try to do this before I have it tuned. I currently have stock manifolds and cats mated to a Corsa cat back.

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