2014+ Exhaust Systems & Mufflers

[Riddick1224]

I had the Borla 400130 installed today in place of the OEM muffler.  There is hardly any change.  Do the 3rd cats on these trucks really muffle the exhaust that much?  I left the resonator on because the shop said it was straight through and didn't have any effect on the exhaust.  It doesn't sound any louder at start up than before.
 
Might should have gotten the Magnaflow 12259 like others on here have said.  Ugh! 
 
Can you clean out the 3rd cat and reinstall it so it looks like nothing was done?
 
 

You can just take the 3rd cat off. You really only need the 2 main ones.

Does anybody have a vid of a 2016 or newer 5.3liter Silverado with a Flowmaster Super 44 on it?


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[jgraves13]

I had the Borla 400130 installed today in place of the OEM muffler.  There is hardly any change.  Do the 3rd cats on these trucks really muffle the exhaust that much?  I left the resonator on because the shop said it was straight through and didn't have any effect on the exhaust.  It doesn't sound any louder at start up than before.
 
Might should have gotten the Magnaflow 12259 like others on here have said.  Ugh! 
 
Can you clean out the 3rd cat and reinstall it so it looks like nothing was done?
 
 

Take the resonator out. It's specifically there to quiet the exhaust down. I would take that out before I'd touch the cat


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[Jaychevy81]

I did the cat back magnaflow kit it’s def not quiet sounds great to. Dual sides behind rear tires.


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[Dearmosd]

The more I read the resonator helps frequencies that are more consistent versus the bulk sound reduction like a muffler

[jimbrown1]

1 hour ago, Dearmosd said:

The more I read the resonator helps frequencies that are more consistent versus the bulk sound reduction like a muffler

That’s what I’m hearing as well.  But when I installed the Borla on my 2011 Silverado with the 5.3 it definitely sounded good.  This time on a 2018 it’s barely louder than stock.  Trying to figure out why that is and what’s different from the older model trucks to today.  Is it the cats are much quieter, the 3rd cat or the resonator.  

 

Only other guess i have is that I was sent the touring muffler and not the S type muffler.

Edited March 22, 2019 by jimbrown1

[KARNUT]

The resonator is just part of the factory high flow exhaust. In the (old) days they did it with very restricted cat and muffler. Three cats and two mufflers today. I haven’t looked I expect more with the split fire engine.


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[jimbrown1]

14 minutes ago, KARNUT said:

The resonator is just part of the factory high flow exhaust. In the (old) days they did it with very restricted cat and muffler. Three cats and two mufflers today. I haven’t looked I expect more with the split fire engine.


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Joey says it’s the 3rd cat.  

[KARNUT]

Joey says it’s the 3rd cat.  

Third cat for? I’ve read the third cat is for California. It does noise reduction too.

 

 

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[FlipZ71]

I removed the 3rd cat on mine , definitely a deeper tone

[Snowcamo]

I removed the 3rd cat on mine , definitely a deeper tone

Did you have any codes pop up after the cat removal?

[FlipZ71]

4 minutes ago, Snowcamo said:

5 minutes ago, FlipZ71 said:

I removed the 3rd cat on mine , definitely a deeper tone

Did you have any codes pop up after the cat removal?

No ,no codes ,  there isn't any sensors on the third cat.

I had mine cut right before it y's together removed it and ran 2 1/2  duel all the way out back. 

[Snowcamo]

No ,no codes ,  there isn't any sensors on the third cat.
I had mine cut right before it y's together removed it and ran 2 1/2  duel all the way out back. 

Right on man! Good to know. Thanks!

[jimbrown1]

Borla changed the design on the 400130, previously GMPP 19131347, so it takes 800-1200 miles to break in.  More to come once I get more miles on the truck.  

[2018GMC]

On 3/21/2019 at 6:10 PM, jimbrown1 said:

I had the Borla 400130 installed today in place of the OEM muffler.  There is hardly any change.  Do the 3rd cats on these trucks really muffle the exhaust that much?  I left the resonator on because the shop said it was straight through and didn't have any effect on the exhaust.  It doesn't sound any louder at start up than before.

 

Might should have gotten the Magnaflow 12259 like others on here have said.  Ugh! 

 

Can you clean out the 3rd cat and reinstall it so it looks like nothing was done?

 

 

Give it a month to break in. The magnaflow 12909 / 14909 was a little noticeable vs stock on cold starts when first put on. After 600 miles it has gotten louder since the muffler packing has broken in. I had stock muffler and flapper cut out. Left resonator. Very happy with it on my 6.2L

Edited March 23, 2019 by 2009GMC

[langston1726]

I just installed some Texas Speed longtubes with catted Y pipe and a Blackwidow Venom 250. Little bit on the raspy side and I’m pretty sure the cold starts wake the dead. I’m sure my neighbors are happy. I’m going to put a AFe resonator in front of the muffler to tone in down a touch.

 

 

 

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