2021 C63S secondary cat delete vibration
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Member
Joined: Jul 2013
Posts: 94
Likes: 6
2026 C63SE AMG, 2023 Mclaren 720s Spider
2021 C63S secondary cat delete vibration
So long story short I had a 2018 c63 S and a 2019 GTC coupe and did secondary cat delete on both. Both cars had zero issues with the cat delete. Traded GTC in for a Mclaren 600lt coupe and got a gle53 as daily. After a few month realized I didnt need SUV so ended up getting a 2021 C63S Coupe.
So as usual I got my secondary cat delete and first thing i noticed was the secondary cats on the 2021 were alot bigger and hand 2 brackets that are mounted on the side of the car.
After the cats came off I noticed this crazy rubbing/vibration sound at low rpms. Pretty much if my foots on the gas from a standstill and up to about 2k rpm i feel this vibration on the gas pedal and this very loud buzzing sound from where downpipe section of the car.
I thought maybe because there brackets were no longer connected and the exhaust as vibrating so I had the shop mount some brackets onto where the secondary cats used to be and the problem got a little better but still makes this vibration/buzzing sound.
I noticed the car does not do this when its cold. It also makes a slight buzzing/vibration going above 6krpm.
Any one else have this problem on a 2021 c63? Car sounds great but this buzzing sound is driving me insane.
Its def not the H valve because we checked it and the sound is 100% coming from where the secondary cats used to be.
Do you guys think the welder did a poor job? used cheap material? or maybe just the exhaust is now moving more because the brackets are not connected?
Trying to see if i can get some answers here before i ordered catted redstar downpipes.
So as usual I got my secondary cat delete and first thing i noticed was the secondary cats on the 2021 were alot bigger and hand 2 brackets that are mounted on the side of the car.
After the cats came off I noticed this crazy rubbing/vibration sound at low rpms. Pretty much if my foots on the gas from a standstill and up to about 2k rpm i feel this vibration on the gas pedal and this very loud buzzing sound from where downpipe section of the car.
I thought maybe because there brackets were no longer connected and the exhaust as vibrating so I had the shop mount some brackets onto where the secondary cats used to be and the problem got a little better but still makes this vibration/buzzing sound.
I noticed the car does not do this when its cold. It also makes a slight buzzing/vibration going above 6krpm.
Any one else have this problem on a 2021 c63? Car sounds great but this buzzing sound is driving me insane.
Its def not the H valve because we checked it and the sound is 100% coming from where the secondary cats used to be.
Do you guys think the welder did a poor job? used cheap material? or maybe just the exhaust is now moving more because the brackets are not connected?
Trying to see if i can get some answers here before i ordered catted redstar downpipes.
Member
Joined: Sep 2020
Posts: 172
Likes: 10
From: Toronto
c63s coupe, bmw 335i coupe (winterbeater)
Secondary cat inquiry
Hey I came across your thread about secondary cats. Just wondering if you got the oem ones or willing to sell them? I’m importing my car to Europe so I need to put them back on in order to pass emissions, shoot me a text or email if your willing to sell them.
6474665652
briancanadiano@gmail.com
6474665652
briancanadiano@gmail.com
