Just did the secondary cat delete
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Joined: Feb 2017
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AMG C43
Just did the secondary cat delete
So after reading all the positive comments I took my 2019 63S in and had the secondary cats cut out. Let me tell you what a difference. Way more growl and much throatier sound. I took a before and after video but honestly the video doesn’t even cone close to doing it justice. Pretty sure I burned half a tank of gas just driving around with the windows down and no radio after I picked it up. Lol
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Joined: Oct 2019
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From: AZ
2018 C63S Coupe
Dang! I seriously need to get this done on my AMG! Thanks for sharing. I too would be interested in the videos.
I already know the shop because I had them cut out the resonators on my Lexus RCF and they weld in the straight pipes the correct way so no chance of leaking and it cost me $200. I need to go see them soon!!!
I already know the shop because I had them cut out the resonators on my Lexus RCF and they weld in the straight pipes the correct way so no chance of leaking and it cost me $200. I need to go see them soon!!!
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Joined: Nov 2019
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From: Bay Area, CA
2020 AMG C63s
Sorry for the noob question here but when you remove the secondary cat, are you able to pass smog (specifically in CA)? And are you able to put the secondary cat back on (easily) should you need to pass smog?
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AMG C43
you will still pass emissions as the primary handles that work. As for putting it back on easily, my shop guy said it would be a pain in the rear.
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From: Bay Area, CA
2020 AMG C63s
So, I guess the next logical question is why did MB even bother with the secondary cats if the primaries can pass smog here in the US? Is this where that infamous OPF filter lives?
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AMG C43
im sure someone besides me is more qualified to answer this, but my shop guy said from what he could tell the secondary cat served no purpose other than further reducing exhaust noise and stated it was very restrictive. No sensors or anything that her could see.
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MY17 C63s Sedan
Not so fast. Just because you pass the sniffer test does not mean you will pass the visual inspection. So depending on the shop you go to or the inspector on that day, they can definitely fail you if they want just based on the removal of the secondary cats. So just be aware.
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2023 Urus Performante 2018 Huracan Perf. - 2017 Ferrari 488 GTB
Removing secondary cats will cause resonance/drone and most likely regret and hassle (compliance/dealer/resell) down the road. Best thing is to spend the money on a quality valved (exhaust that can easily be returned back to stock. In order to avoid the previously mentioned issues - just my opinion.
Last edited by benzbell; Dec 18, 2019 at 11:16 AM.
Junior Member
Joined: Feb 2015
Posts: 39
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From: AZ
2018 C63S
Dang! I seriously need to get this done on my AMG! Thanks for sharing. I too would be interested in the videos.
I already know the shop because I had them cut out the resonators on my Lexus RCF and they weld in the straight pipes the correct way so no chance of leaking and it cost me $200. I need to go see them soon!!!
I already know the shop because I had them cut out the resonators on my Lexus RCF and they weld in the straight pipes the correct way so no chance of leaking and it cost me $200. I need to go see them soon!!!
Thread Starter
Junior Member
Joined: Feb 2017
Posts: 25
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AMG C43
Removing secondary cats will cause resonance/drone and most likely regret and hassle (compliance/dealer/resell) down the road. Best thing is to spend the money on a quality valved (exhaust that can easily be returned back to stock. In order to avoid the previously mentioned issues - just my opinion.
Thread Starter
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AMG C43
Thread Starter
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AMG C43
CAT Removed
Hard to really hear the difference with an iPhone but much deeper sound. I’ll take a video later outside.
also the pops and crackles happen around 4K RPMs and almost all the time on downshifts now. Prior I got none on downshifts.
Hard to really hear the difference with an iPhone but much deeper sound. I’ll take a video later outside.
also the pops and crackles happen around 4K RPMs and almost all the time on downshifts now. Prior I got none on downshifts.
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From: AZ
2018 C63S Coupe
It is called Performance Muffler https://www.performancemuffler.net/
They have two shops...I went to the Phoenix shop and the guy new what he was doing.
Phoenix
15812 N 32nd St Ste B #8
Phoenix, AZ 85032
602-765-0035
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From: AZ
2018 C63S
It is called Performance Muffler https://www.performancemuffler.net/
They have two shops...I went to the Phoenix shop and the guy new what he was doing.
Phoenix
15812 N 32nd St Ste B #8
Phoenix, AZ 85032
602-765-0035
They have two shops...I went to the Phoenix shop and the guy new what he was doing.
Phoenix
15812 N 32nd St Ste B #8
Phoenix, AZ 85032
602-765-0035
Let me know if you get it done there and how it goes, I'm probably going to do this too in a couple months.
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From: AZ
2018 C63S Coupe
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From: Earth
C63S, 2004 S4, 2001 S4 Avant
Removing secondary cats will cause resonance/drone and most likely regret and hassle (compliance/dealer/resell) down the road. Best thing is to spend the money on a quality valved (exhaust that can easily be returned back to stock. In order to avoid the previously mentioned issues - just my opinion.
To Daniel Jay - thank you for posting your experience on a FL model. Now I have to find a reliable shop to do this. Did they weld or clamp the replacement pipe?
Thread Starter
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AMG C43
If the OEM exhaust has resonators, those usually take care of the resonance and drone. This was a common mod on the W204 as the secondaries were easily accessible and also produced more AMG noise without drone/resonance.
To Daniel Jay - thank you for posting your experience on a FL model. Now I have to find a reliable shop to do this. Did they weld or clamp the replacement pipe?
To Daniel Jay - thank you for posting your experience on a FL model. Now I have to find a reliable shop to do this. Did they weld or clamp the replacement pipe?
