Two Different GM Cat Back Exhausts

ShapeShifter · Aug 4, 2023

Everyone who talks about the GM performance cat back seems to be referring to the "Borla" system offered through GM. There is also some debate about whether it is closer to the S-Type or Touring model. But there is also a non-Borla system. Anyone have any experience with the differences (sound wise) between the two?

GM Borla System, Part Number 19419433

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GM Non-Borla System, Part Number 84964744

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BMCAT4 · Aug 4, 2023

I have what you labeled as the “NON-Borla” system. However, I called Borla because I did not like the HDMI exhaust ports and wanted to replace them with the Borla Quad Tips. At minimum over the phone, Borla confirmed both systems were manufactured by Borla. Matter of fact, before they agreed to send me tips and the two tailpipe sections they wanted to confirm I had the version which was a single inlet and single outlet. I received the parts yesterday and plan on putting everything together tomorrow so I may find out differently but as of today, I believe Borla manufactures both.

ShapeShifter · Aug 4, 2023

Interesting that the more expensive one is the one that comes without new tips. The one with new tips, which is the one explicitly labelled as Borla, is cheaper. I might just get the official Borla Touring and call it a day. Get it installed by a licensed mechanic and it would be hard to any GM dealer to deny warranty based on that.

ShapeShifter · Aug 4, 2023

BMCAT4 said:
I have what you labeled as the “NON-Borla” system. However, I called Borla because I did not like the HDMI exhaust ports and wanted to replace them with the Borla Quad Tips. At minimum over the phone, Borla confirmed both systems were manufactured by Borla. Matter of fact, before they agreed to send me tips and the two tailpipe sections they wanted to confirm I had the version which was a single inlet and single outlet. I received the parts yesterday and plan on putting everything together tomorrow so I may find out differently but as of today, I believe Borla manufactures both.

@BMCAT4 how do you find the sound of that system compared to stock? How is the cold start? I want rumble but I don't want to piss off my neighbors when I frequently leave the house at 5am.

BMCAT4 · Aug 4, 2023

It is substantially louder than stock. However, stock exhaust sounds like a brother sewing machine. So the comparison is less than fair. But most of the sound is on cold start. Not sure how the tips are going to impact the sound I can let you know later this weekend. Interstate driving is quiet if you don't "get on it" to pass someone you would not know anything is different which I like.

I'll try to post a video after the installation.

ShapeShifter · Aug 4, 2023

Yeah the stock exhaust is the worst thing about this truck.

adeerchaser · Aug 4, 2023

I have a 22 AT4x, I got my exhaust thru from GM and installed by a GM dealership. They said that not only does it not affect my warranty, but it is also covered. It is made by Borla. The system sounds great, but I must say- on start up it does bark pretty loud. And mine is under the truck as X’s do not come thru bumper.