Next Level Auto Brokers
BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read

Go Back   BMW M3 and BMW M4 Forum > BMW F80 M3 / F82 M4 Technical Topics > Mechanical Maintenance: Break-in | Oil & Fluids | Servicing | TSB | Recalls

Post Reply
 
Thread Tools Search this Thread
      08-30-2015, 08:06 PM   #1
kylecronin
New Member
kylecronin's Avatar
1
Rep
5
Posts

Drives: 2015 M4
Join Date: Mar 2015
Location: Boston Area

iTrader: (0)

What is this sound? Is it normal?

I've had my F82 (DCT) for a little over 5 months and put about 14,000 miles on it. I've noticed a sound for a little while, sort of a vibration at 1500RPM or so at 50+% throttle. It's not super loud and it doesn't appear to affect the performance of the car, but I'm wondering if anyone can tell me what it is, and if it's something I should try and have fixed. I don't know if the car has always made this sound, or if it's something new.

I uploaded a clip here:

https://soundcloud.com/kyle-cronin/m4-sound

This audio was recorded with a microphone dangling outside the bottom of the driver's door. In this clip, I'm in 3rd gear at about 1000RPM. I then give about 50% throttle, and as the tach passes 1500RPM you can hear the metallic vibrating sound. As the RPMs continue to climb the sound disappears.

I also recorded the engine and the exhaust by putting a microphone near the wipers and dangling a microphone out the tailgate, both of which did not register the sound. It must be coming from underneath the center of the car.

Last edited by kylecronin; 08-31-2015 at 09:52 AM..
Appreciate 0
      08-30-2015, 08:26 PM   #2
BavarianDevil
Private First Class
BavarianDevil's Avatar
United_States
52
Rep
137
Posts

Drives: 2015 BMW M4 Silverstone/Beige
Join Date: Jul 2015
Location: Almaden Valley, South San Jose, CA

iTrader: (0)

track not found
Appreciate 0
      08-30-2015, 08:28 PM   #3
kylecronin
New Member
kylecronin's Avatar
1
Rep
5
Posts

Drives: 2015 M4
Join Date: Mar 2015
Location: Boston Area

iTrader: (0)

Quote:
Originally Posted by BavarianDevil View Post
track not found
Sorry about that! I had the wrong permissions on the upload. It should work now.
Appreciate 0
      08-31-2015, 02:06 PM   #4
mad chemist
Lieutenant
mad chemist's Avatar
United Kingdom
58
Rep
416
Posts

Drives: F82 M4
Join Date: Feb 2008
Location: South East

iTrader: (0)

It's the exhaust valves resonating.


Quote:
Originally Posted by kylecronin View Post
I've had my F82 (DCT) for a little over 5 months and put about 14,000 miles on it. I've noticed a sound for a little while, sort of a vibration at 1500RPM or so at 50+% throttle. It's not super loud and it doesn't appear to affect the performance of the car, but I'm wondering if anyone can tell me what it is, and if it's something I should try and have fixed. I don't know if the car has always made this sound, or if it's something new.

I uploaded a clip here:

https://soundcloud.com/kyle-cronin/m4-sound

This audio was recorded with a microphone dangling outside the bottom of the driver's door. In this clip, I'm in 3rd gear at about 1000RPM. I then give about 50% throttle, and as the tach passes 1500RPM you can hear the metallic vibrating sound. As the RPMs continue to climb the sound disappears.

I also recorded the engine and the exhaust by putting a microphone near the wipers and dangling a microphone out the tailgate, both of which did not register the sound. It must be coming from underneath the center of the car.
Appreciate 0
      08-31-2015, 04:07 PM   #5
kylecronin
New Member
kylecronin's Avatar
1
Rep
5
Posts

Drives: 2015 M4
Join Date: Mar 2015
Location: Boston Area

iTrader: (0)

Quote:
Originally Posted by mad chemist View Post
It's the exhaust valves resonating.
OK, that's good to know, thanks. Is it normal? Is it something I can have fixed?
Appreciate 0
      09-02-2015, 02:31 PM   #6
mad chemist
Lieutenant
mad chemist's Avatar
United Kingdom
58
Rep
416
Posts

Drives: F82 M4
Join Date: Feb 2008
Location: South East

iTrader: (0)

Quote:
Originally Posted by kylecronin View Post
OK, that's good to know, thanks. Is it normal? Is it something I can have fixed?
100% normal for most early cars. I think LCI ones have modified exhaust valve assemblies.

Dealer will change out the exhaust it if it really bugs you as it's a known fault.

You could remove the internal spring in each valve housing and stretch it out a bit and then re-fit. Worked for me but it is a PITA to re-fit the spring into the valve assembly.

Mad.
Appreciate 0
Post Reply

Bookmarks

Tags
dct, sound, vibration

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 08:28 PM.




f80post
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