2nd cats delete sound - Page 2

ender2664 · 05-26-2016, 09:36 PM

Have their been any guys with catbacks that had the cel light activate?
If not that is strong evidence for your theory.

SS 1LE · 05-26-2016, 09:52 PM

My buddy deleted the secondary cats months ago...no CEL's.

chaacole · 05-26-2016, 10:18 PM

To soon to tell with 6th gens but with 5th gens I don't believe there have been any cel's with bolt on catback kits

buh · 05-29-2016, 12:15 PM

Anyone ever considered/tried putting a small muffler in place of the secondary cats?

I'm looking for a way to make the engine sound more 'tuned' instead of like NASCAR.

STEVE41 · 05-29-2016, 10:51 PM

anyone just punch out the 2nd cats yet?

Tr6 · 05-30-2016, 10:47 AM

Quote:

Originally Posted by STEVE41

anyone just punch out the 2nd cats yet?

It's much easier to get it replaced. You have to cut them out to even try to punch out the cats so... why bother and just replace it? You can buy 2.75' straight pipes right on ebay/amazon that can be cut a little bit and welded if you want to match the exhaust diameter of 2.75' as 99.9% of exhaust shops only have 2.5' or 3.0'.

Sub · 04-12-2017, 08:31 AM

Bumping this thread.. any concensus now on what throws the code? Also, any before and after description of the increase in sound?! Video available? Thanks.

Hagels316 · 04-12-2017, 09:34 AM

The first exhaust mod I ever did was removing the secondary cats. I replaced them with welded 3inch straight pipes. I never got a CEL.

pinoyscorpion951 · 04-12-2017, 09:45 AM

Quote:

Originally Posted by Sub

Bumping this thread.. any concensus now on what throws the code? Also, any before and after description of the increase in sound?! Video available? Thanks.

I'm running Kooks long tube headers now but for almost a year, I had the secondary cats deleted and replaced with a straight pipe. I only threw a CEL once and that was from the PRIMARY cats had bolts that were loose. Never had a CEL related to the secondary cat removal. If you do have it done, make sure the person doing the welds is competent. The top portion of the pipe is tricky to get to. As for the video, Lethal made one to give you an idea about the sound. It is about 10-15 percent louder at idle and startup and stupid loud at WOT.

Sub · 04-14-2017, 02:28 PM

So if we make sure there are no leaks, then we dont get the CEL?

What will GM think of this mod? Deny warranty work?!

SuperSound · 04-14-2017, 09:23 PM

Quote:

Originally Posted by Sub

So if we make sure there are no leaks, then we dont get the CEL?

What will GM think of this mod? Deny warranty work?!

Cats are Federal emissions equipment, so are covered by a separate warranty. Legally that means it can't impact your Powertrain warranty because it was never covered by it. Same story for the secondary o2s and primary cats.

DD goat · 04-14-2017, 09:39 PM

Used Borla 60606. No CEL, and sound is noticeably louder when on the gas. Just right!

masoch · 04-15-2017, 04:26 AM

Quote:

Originally Posted by SuperSound

Cats are Federal emissions equipment, so are covered by a separate warranty. Legally that means it can't impact your Powertrain warranty because it was never covered by it. Same story for the secondary o2s and primary cats.

Can anyone corroborate these statements? My cats are gone if so.

TJay74 · 04-15-2017, 09:18 AM

CAT's are part of the emissions system, as long as the front O2 sensors are in place the GM shouldn't have any issues as those are the sensors that determine fueling changes. The rear O2 sensors after the primary cats only tell the ECM if the cats are working or not.

In a quick blip here is what happened. GM used to make 2 set of each vehicle, a 49 state vehicle and a California vehicle. The 49 state vehicles only had primary cats, the CA vehicles due to the CARB requirements had primary and secondary cats. Financially GM chose to eliminate the separate lines of production in 2008 and offer a 50 state complaint vehicle, so now all vehicles comes with the CA CARB complaint primary and secondary cat system.

The secondary cats are not monitored, so they can be cut out with no issues. I removed mine before I even had 1000 miles on the car. I have NPP on my car, as said it is noticeable louder at start up until the exhaust warms up and settles down. It is about 15-20 louder when driving around.

It is 30% louder when under WOT, like almost a whole nother animal kind of thing. Enough that my wife who drives a 2016 Audi SQ5 that is modified with a full exhaust system that is pretty aggressive even noticed it when I made the change to my car about how much louder it got.

04-12-2017, 08:31 AM	#21
Sub Drives: 2017 ZL1 Join Date: Oct 2016 Location: Ny Posts: 859	Bumping this thread.. any concensus now on what throws the code? Also, any before and after description of the increase in sound?! Video available? Thanks. __________________ My Car Blog and mods. Previous Chevys: 2016 2ss, 2015 C7 z51, 2004 C5 Z06

04-14-2017, 02:28 PM	#24
Sub Drives: 2017 ZL1 Join Date: Oct 2016 Location: Ny Posts: 859	So if we make sure there are no leaks, then we dont get the CEL? What will GM think of this mod? Deny warranty work?! __________________ My Car Blog and mods. Previous Chevys: 2016 2ss, 2015 C7 z51, 2004 C5 Z06

05-26-2016, 09:36 PM	#15
ender2664 Account Suspended Drives: 2016 2SS Join Date: Mar 2014 Location: Palm Desert Posts: 2,353	Have their been any guys with catbacks that had the cel light activate? If not that is strong evidence for your theory.

05-26-2016, 09:52 PM	#16
SS 1LE マスタング = 遅い Drives: 2017 Chevrolet Camaro SS 1LE Join Date: Aug 2015 Location: Florida Posts: 7,061	My buddy deleted the secondary cats months ago...no CEL's.

05-26-2016, 10:18 PM	#17
chaacole Drives: 2016 Camaro 1ss Join Date: Apr 2016 Location: Memphis Posts: 47	To soon to tell with 6th gens but with 5th gens I don't believe there have been any cel's with bolt on catback kits

05-29-2016, 12:15 PM	#18
buh Drives: NA Join Date: May 2016 Location: Texas Posts: 12	Anyone ever considered/tried putting a small muffler in place of the secondary cats? I'm looking for a way to make the engine sound more 'tuned' instead of like NASCAR.

05-29-2016, 10:51 PM	#19
STEVE41 Drives: 2016 SS Join Date: Jan 2016 Location: PHOENIX Posts: 156	anyone just punch out the 2nd cats yet?

04-12-2017, 09:34 AM	#22
Hagels316 Drives: 2016 Camaro 2SS A8 Join Date: Dec 2015 Location: Charlotte, NC Posts: 161	The first exhaust mod I ever did was removing the secondary cats. I replaced them with welded 3inch straight pipes. I never got a CEL.

04-14-2017, 09:39 PM	#26
DD goat Drives: 2017 Hyper Blue Camaro 2SS Join Date: Aug 2016 Location: Grayling Michigan Posts: 94	Used Borla 60606. No CEL, and sound is noticeably louder when on the gas. Just right!

04-15-2017, 09:18 AM	#28
TJay74 Drives: 17 Camaro SS 1LE & 16 Sierra AT CC Join Date: Nov 2016 Location: Norman, OK Posts: 2,424	CAT's are part of the emissions system, as long as the front O2 sensors are in place the GM shouldn't have any issues as those are the sensors that determine fueling changes. The rear O2 sensors after the primary cats only tell the ECM if the cats are working or not. In a quick blip here is what happened. GM used to make 2 set of each vehicle, a 49 state vehicle and a California vehicle. The 49 state vehicles only had primary cats, the CA vehicles due to the CARB requirements had primary and secondary cats. Financially GM chose to eliminate the separate lines of production in 2008 and offer a 50 state complaint vehicle, so now all vehicles comes with the CA CARB complaint primary and secondary cat system. The secondary cats are not monitored, so they can be cut out with no issues. I removed mine before I even had 1000 miles on the car. I have NPP on my car, as said it is noticeable louder at start up until the exhaust warms up and settles down. It is about 15-20 louder when driving around. It is 30% louder when under WOT, like almost a whole nother animal kind of thing. Enough that my wife who drives a 2016 Audi SQ5 that is modified with a full exhaust system that is pretty aggressive even noticed it when I made the change to my car about how much louder it got.

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