BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read
M2 Technical Topics > N55 Engine / Drivetrain / Exhaust / Bolt-ons / Tuning > AA high flow downpipe question

Post Reply
 
Thread Tools Search this Thread
      12-17-2020, 12:02 PM   #1
ryancastano
Registered
2
Rep
4
Posts

Drives: BMW M2
Join Date: Nov 2020
Location: Las Vegas

iTrader: (0)

AA high flow downpipe question

Hi all,

I recently installed an Active Autowerke high flow dp on my OG M2. I also have an MPE with a muffler delete. During the first few days of driving, my car sounded exactly as I had expected. It sounded more throaty and I could hear significantly more of the good noises inside the car. Now 2 weeks later, my car sounds muffled again. I'm simply not hearing the same tone and even sounds muffled despite high load. Just the dreaded drone between 3k-4k.

Perhaps it's me getting used to the noise?

Could someone maybe enlighten me *

(AA does hold their promise of no CEL and the product was built well, so no complaints there)
Appreciate 0
      12-17-2020, 12:34 PM   #2
CalAcacian
Lieutenant
537
Rep
560
Posts

Drives: 2018 M2
Join Date: Sep 2020
Location: Orange County, California

iTrader: (0)

It's possible, but very unlikely, that you have a melted cat element. Are you on the stock tune or something different?
Appreciate 0
      12-17-2020, 08:45 PM   #3
ryancastano
Registered
2
Rep
4
Posts

Drives: BMW M2
Join Date: Nov 2020
Location: Las Vegas

iTrader: (0)

Quote:
Originally Posted by CalAcacian View Post
It's possible, but very unlikely, that you have a melted cat element. Are you on the stock tune or something different?
No tune I'm stock
Appreciate 0
      12-17-2020, 09:28 PM   #4
Oktom2
Private First Class
Oktom2's Avatar
South Korea
14
Rep
83
Posts

Drives: 17 KIA Stinger GT, 17 BMW M2
Join Date: Nov 2020
Location: Korea

iTrader: (0)

My sound was like that.
Muffled and only the drone. It was the cat that had melted.
Appreciate 0
      12-18-2020, 01:18 AM   #5
ryancastano
Registered
2
Rep
4
Posts

Drives: BMW M2
Join Date: Nov 2020
Location: Las Vegas

iTrader: (0)

Quote:
Originally Posted by Oktom2 View Post
My sound was like that.
Muffled and only the drone. It was the cat that had melted.
Did you get a CEL? I've only had it for 2 weeks
Appreciate 0
      12-18-2020, 12:35 PM   #6
Oktom2
Private First Class
Oktom2's Avatar
South Korea
14
Rep
83
Posts

Drives: 17 KIA Stinger GT, 17 BMW M2
Join Date: Nov 2020
Location: Korea

iTrader: (0)

Quote:
Originally Posted by ryancastano View Post
Did you get a CEL? I've only had it for 2 weeks
Yes I had a CEL
Appreciate 0
      12-21-2020, 07:23 AM   #7
mike@x-ph.com
BimmerPost Supporting Vendor
mike@x-ph.com's Avatar
United_States
23784
Rep
190,103
Posts


Drives: 07-335/12-328/18-M4/21-M4CP
Join Date: Sep 2013
Location: Las Vegas

iTrader: (23)

Quote:
Originally Posted by Oktom2 View Post
My sound was like that.
Muffled and only the drone. It was the cat that had melted.
If the cat melted, he would get a CEL . I dont think thats the case since he does not have any codes
__________________
Check out our current sale by clicking on this link!
https://x-ph.com/sale/

Phone number 702-494-9435
Appreciate 0
      12-21-2020, 08:37 AM   #8
nioh_lbbm2
Lieutenant Colonel
nioh_lbbm2's Avatar
1717
Rep
1,899
Posts

Drives: M2
Join Date: Mar 2018
Location: California

iTrader: (0)

Two possibilities and the only way to know for sure is to uninstall and visually check.

Either your cat core melted/physically broke. This would be easy to visually check once uninstalled.

Or the inside of your MPE muffler box is damaged in some manner (baffles, packing material, etc) This would be harder to visually verify. Might be able to shake to see if you hear components rattling or snake in a bore scope.
Or cut it open.
If I recall correctly, this happened to some BMW MPE on various M models so it's certainly in the realm of possibility but you would probably notice rattling or something.

Should probably find another owner near you to compare exhaust noise before you go the cutting route. Maybe you're just used to the exhaust note now.
Appreciate 0
      12-22-2020, 07:40 AM   #9
mike@x-ph.com
BimmerPost Supporting Vendor
mike@x-ph.com's Avatar
United_States
23784
Rep
190,103
Posts


Drives: 07-335/12-328/18-M4/21-M4CP
Join Date: Sep 2013
Location: Las Vegas

iTrader: (23)

Quote:
Originally Posted by nioh_lbbm2 View Post
Two possibilities and the only way to know for sure is to uninstall and visually check.

Either your cat core melted/physically broke. This would be easy to visually check once uninstalled.

Or the inside of your MPE muffler box is damaged in some manner (baffles, packing material, etc) This would be harder to visually verify. Might be able to shake to see if you hear components rattling or snake in a bore scope.
Or cut it open.
If I recall correctly, this happened to some BMW MPE on various M models so it's certainly in the realm of possibility but you would probably notice rattling or something.

Should probably find another owner near you to compare exhaust noise before you go the cutting route. Maybe you're just used to the exhaust note now.
+1

If you know someone local with this setup, compare how his car sounds. If not, put the car on a lift an do a visual check
__________________
Check out our current sale by clicking on this link!
https://x-ph.com/sale/

Phone number 702-494-9435
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 03:14 AM.




m2
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST