Resonators or Cats

B_rad1969 · 06-23-2019, 06:28 AM

I have a debate going on about what is behind the cats. The rectangular things. I'm saying they are resonators and not catalytic converters. Having 4 catalytic converters make no sense. I know everyone is calling them secondary cats but that's not really what they are. They serve no purpose with regard to emissions.

enzia35 · 06-23-2019, 07:00 AM

I believe they are cats, just not monitored.

B_rad1969 · 06-23-2019, 07:07 AM

I don't see that part listed anywhere. You can find the converters but not that. I don't want to know what people think they are. We already know that!.!.

6spdhyperblue · 06-23-2019, 08:02 AM

they’re cats. Fact.

Have you seen the insides of them? Plenty of people have by now, there’s honeycomb cells in there.

B_rad1969 · 06-23-2019, 08:51 AM

Quote:

Originally Posted by 6spdhyperblue

they’re cats. Fact.

Have you seen the insides of them? Plenty of people have by now, there’s honeycomb cells in there.

Someone had cut one open on here and it didn't look like a cat on the inside. It looked kinda like a muffler.

Joshinator99 · 06-23-2019, 09:00 AM

Quote:

Originally Posted by B_rad1969

I have a debate going on about what is behind the cats. The rectangular things. I'm saying they are resonators and not catalytic converters. Having 4 catalytic converters make no sense. I know everyone is calling them secondary cats but that's not really what they are. They serve no purpose with regard to emissions.

They are cats. They are there for California emissions requirements. But, since they are not monitored by the ECM, they can be quickly and easily launched with no fault code.

B_rad1969 · 06-23-2019, 09:06 AM

They aren't even listed... It's a big secret by Chevy. #1&2 if you look are both converters for different applications. Probably NA and ZL1.
Hope this link works.
https://www.gmpartscenter.net/auto-p...umber=84465354

6spdhyperblue · 06-23-2019, 10:21 AM

Quote:

Originally Posted by B_rad1969

Someone had cut one open on here and it didn't look like a cat on the inside. It looked kinda like a muffler.

No there are cells inside. Looks just like the primary cats inside but larger less restrictive cells

Mosaic6SS · 06-23-2019, 01:57 PM

Anyone have any pics of the insides? The parts list and the repair manuals list the additional muffler equipment as “mufflers” and not cats. The two forward bolt on cats are listed as catalytic converters. I am still thinking they are resonators. I think the reason the California emissions is being thrown in there is because maybe the state law considers noise pollution under the same statute. So GM added resonators to comply with a stricter Cali dB law level.

Ryephile · 06-25-2019, 08:37 AM

Quote:

Originally Posted by B_rad1969

They aren't even listed... It's a big secret by Chevy. #1&2 if you look are both converters for different applications. Probably NA and ZL1.
Hope this link works.
https://www.gmpartscenter.net/auto-p...umber=84465354

Hover over #11 in that diagram. It says "Heat Shield...Converter".

Quote:

Originally Posted by Mosaic6SS

Anyone have any pics of the insides? The parts list and the repair manuals list the additional muffler equipment as “mufflers” and not cats...

No, it says "muffer", not plural.

FrostySS · 06-25-2019, 09:04 AM

They're cats bud...

KingLT1 · 06-25-2019, 09:06 AM

They are a cat but are not built the same as the primary cats. Different material on the inside that resembles the primaries...they are to help burn off hydrocarbons on cold starts since the front primary cats are not effective until they reach a certain temp.

Umbriel · 06-25-2019, 09:42 AM

Definitely cats and not monitored like previously stated.

Trochoidal · 06-25-2019, 05:47 PM

This company also talks about stock exhaust.

https://www.mishimoto.com/engineerin...system-review/

06-23-2019, 07:00 AM	#2
enzia35 Drives: '16 Garnet Red 1SS Join Date: Mar 2014 Location: College Station, TX Posts: 3,450	I believe they are cats, just not monitored. __________________ '16 Camaro 1SS '18 Miata GT Gone: '01 Camaro, '14 Camaro, '90 Miata

06-23-2019, 01:57 PM	#9
Mosaic6SS Drives: Camaro Join Date: May 2019 Location: Earth Posts: 81	Anyone have any pics of the insides? The parts list and the repair manuals list the additional muffler equipment as “mufflers” and not cats. The two forward bolt on cats are listed as catalytic converters. I am still thinking they are resonators. I think the reason the California emissions is being thrown in there is because maybe the state law considers noise pollution under the same statute. So GM added resonators to comply with a stricter Cali dB law level. Last edited by Mosaic6SS; 06-23-2019 at 02:11 PM.

06-25-2019, 09:06 AM	#12
KingLT1 Drives: 2016 1SS NFG A8 Join Date: Aug 2017 Location: 46804 Posts: 6,793	They are a cat but are not built the same as the primary cats. Different material on the inside that resembles the primaries...they are to help burn off hydrocarbons on cold starts since the front primary cats are not effective until they reach a certain temp. __________________ 2016 NFG 1SS A8 Options-2SS Leather/NPP Perf. mods-Whipple 2.9/Fuel System/Flex Fuel/103mm TB/Rotofab Big Gulp/Cat Deletes/Corsa NPP Per. times- 10.5 @ 137 w/ 1.8 60ft Full weight on 20's 1200DA

06-23-2019, 06:28 AM	#1
B_rad1969 Drives: 2013 2lt Join Date: May 2014 Location: Indiana Posts: 72	Resonators or Cats I have a debate going on about what is behind the cats. The rectangular things. I'm saying they are resonators and not catalytic converters. Having 4 catalytic converters make no sense. I know everyone is calling them secondary cats but that's not really what they are. They serve no purpose with regard to emissions.

06-23-2019, 07:07 AM	#3
B_rad1969 Drives: 2013 2lt Join Date: May 2014 Location: Indiana Posts: 72	I don't see that part listed anywhere. You can find the converters but not that. I don't want to know what people think they are. We already know that!.!.

06-23-2019, 08:02 AM	#4
6spdhyperblue Drives: 6th gen Join Date: Aug 2013 Location: US Posts: 3,670	they’re cats. Fact. Have you seen the insides of them? Plenty of people have by now, there’s honeycomb cells in there.

06-23-2019, 09:06 AM	#7
B_rad1969 Drives: 2013 2lt Join Date: May 2014 Location: Indiana Posts: 72	They aren't even listed... It's a big secret by Chevy. #1&2 if you look are both converters for different applications. Probably NA and ZL1. Hope this link works. https://www.gmpartscenter.net/auto-p...umber=84465354

06-25-2019, 09:04 AM	#11
FrostySS Drives: 2018 Redline Edition 2SS Join Date: Dec 2014 Location: Mays Landing, NJ Posts: 778	They're cats bud... __________________ 2018 Redline Edition 2SS- A8, NPP, MRC, Recaro seats, ECS Novi 1500 tuned by EFX, cat deletes, Mighty Mouse Wild CC, GM STB, smoked ZL1 3rd brake light, Xpel XR Black 35% tint all around, Street Scene front splitter, C7 Carbon ZL1 side skirts Drake Muscle Car wicker bill, Adams Polishes Ceramic Coating 2010 Infiniti G37x Sedan for the DD.

06-25-2019, 09:42 AM	#13
Umbriel Drives: 2016 Camaro SS Join Date: Sep 2018 Location: Bartlett, TN Posts: 1,121	Definitely cats and not monitored like previously stated.

06-25-2019, 05:47 PM	#14
Trochoidal Drives: 2017 Camaro 2SS A8 Join Date: May 2019 Location: USA Posts: 1,656	This company also talks about stock exhaust. https://www.mishimoto.com/engineerin...system-review/

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