F30POST
F30POST
2012-2015 BMW 3-Series and 4-Series Forum
BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read
BMW 3-Series and 4-Series Forum (F30 / F32) | F30POST > Technical Forums > N20, N26, B46, B48 Turbo Engine / Drivetrain / Exhaust Modifications > Exhaust drone solution
European Auto Source (EAS)
Post Reply
 
Thread Tools Search this Thread
      08-22-2015, 06:47 PM   #1
Piggieback
Private First Class
31
Rep
137
Posts

Drives: 2014 Cayman S, 2015 A3
Join Date: Feb 2015
Location: chicago

iTrader: (0)

Exhaust drone solution

For anyone who installed AA or other aftermarket exhaust systems, even with straight pipe, you all should be familiar with the drone associated with 2-3k rpm. Very easy and cheap way to fix the problem, purchase dynamat/aftermatket sound deadening, and you can actually fine tune the amount of sound feedback in the cabin, but most notably, this eliminates those low frequencies that basically vibrate the cabin. I used these, and they worked like a charm, only needed 3 pieces, very easy to cut.

http://www.ebay.com/itm/251811573432...%3AMEBIDX%3AIT
Appreciate 1
      08-22-2015, 07:05 PM   #2
ahero4eternity
Major
421
Rep
1,425
Posts

Drives: bmw
Join Date: Jul 2015
Location: usa

iTrader: (4)

So where did you put it?
Appreciate 0
      08-24-2015, 12:06 AM   #3
Piggieback
Private First Class
31
Rep
137
Posts

Drives: 2014 Cayman S, 2015 A3
Join Date: Feb 2015
Location: chicago

iTrader: (0)

Quote:
Originally Posted by ahero4eternity View Post
So where did you put it?
Basically underneath the exhaust you have aluminum heat shields, those come of rather easily, you have a few options, you can stick the matt to the back of the aluminum shield, or to the bottom of the car. The great thing about this sound matt, is that you can basically fine tune the sound to your liking. I was slightly put off by the low base like frequencies after 2K rpm, the cabin would vibrate, and this solution allowed me to keep the fun factor and keep my comfort.
Appreciate 0
      08-24-2015, 12:49 AM   #4
wicked_ink
part-time optimist
wicked_ink's Avatar
United_States
6
Rep
72
Posts

Drives: '12 Alpine White F30 335i
Join Date: Jul 2015
Location: San Jose, CA

iTrader: (1)

Garage List
Hmm, this might be a good option. Was thinking of doing a J-pipe resonator welded before the muffler.

Did you install this stuff just where the muffler is below the trunk or did you also do the whole length of the pipes?
Appreciate 0
      08-24-2015, 04:59 AM   #5
rustyminded
Major
rustyminded's Avatar
181
Rep
1,464
Posts

Drives: BMW 328i
Join Date: Nov 2012
Location: C

iTrader: (0)

well if you have catless dp with AA I guarantee a drone, so what I did is remove AFE dp and emtpied stock downpipe. result is amazing barely any drone, sound is deep and yet quite but still better than stock and enjoyable to your ears
__________________
F30 328i - 8 auto.. JB4-EWG harness, OCC, Injen Intake, AFE Scoop, AFE dp, AA axle-back - H&R springs, H&R Rear SB, Front Strut, F&R BMS spacers..
Appreciate 0
      08-31-2015, 07:27 PM   #6
Piggieback
Private First Class
31
Rep
137
Posts

Drives: 2014 Cayman S, 2015 A3
Join Date: Feb 2015
Location: chicago

iTrader: (0)

Quote:
Originally Posted by wicked_ink View Post
Hmm, this might be a good option. Was thinking of doing a J-pipe resonator welded before the muffler.

Did you install this stuff just where the muffler is below the trunk or did you also do the whole length of the pipes?
After playing around with many different spots, the biggest difference was when I took two sheets of 8mm insulating mat, put them together and plugged the cavity right above the muffler tips. After basically lining the entire trunk bottom, I noticed a very slight reduction in noise. I tried to analyze why and where the frequencies were entering the cabin. If you take off the rear diffuser, right above it, is basically an empty cavity, leading all the way up to the trunk, and as the sound leaves the muffler tips, the frequencies enter that cavity and resinate all the wall through the chase and into the cabin. The most effective way is to basically plug the cavity right above the muffler tip/tips, this gave me a very noticeable reduction in noise.
Appreciate 2
aps107.00

      08-31-2015, 07:46 PM   #7
Piggieback
Private First Class
31
Rep
137
Posts

Drives: 2014 Cayman S, 2015 A3
Join Date: Feb 2015
Location: chicago

iTrader: (0)

Here are the pictures of how it should look.
Attached Images
  
Appreciate 1
      08-31-2015, 11:57 PM   #8
wicked_ink
part-time optimist
wicked_ink's Avatar
United_States
6
Rep
72
Posts

Drives: '12 Alpine White F30 335i
Join Date: Jul 2015
Location: San Jose, CA

iTrader: (1)

Garage List
Cool, thank you!
Appreciate 0
      09-01-2015, 01:52 AM   #9
rustyminded
Major
rustyminded's Avatar
181
Rep
1,464
Posts

Drives: BMW 328i
Join Date: Nov 2012
Location: C

iTrader: (0)

so this will stand the heat ?!.
yea i barely have drone but there is this low freq. on very low rpm still a bit annoying
Appreciate 0
      09-01-2015, 10:31 AM   #10
mike@x-ph.com
BimmerPost Supporting Vendor
mike@x-ph.com's Avatar
United_States
8916
Rep
99,716
Posts


Drives: 2007 e92 335i / 2013 F30 328
Join Date: Sep 2013
Location: Las Vegas

iTrader: (19)

Good find OP
__________________
Up to 20% OFF Evolution Racewerks
Phone 725-221-5267 || website www.x-ph.com
Appreciate 0
      09-01-2015, 12:29 PM   #11
DanHazelrigg
Private
9
Rep
86
Posts

Drives: 2014 328i MSport EBII
Join Date: Apr 2012
Location: Warsaw/Fort Wayne, IN

iTrader: (1)

Any concerns with this stuff lasting outside the car?
Appreciate 0
      09-02-2015, 11:23 PM   #12
Piggieback
Private First Class
31
Rep
137
Posts

Drives: 2014 Cayman S, 2015 A3
Join Date: Feb 2015
Location: chicago

iTrader: (0)

No concerns whatsoever, this is butyl/aluminum foil, this is the stuff used to seal roof penetrations, and basically the material used to seal commercial roofs, meaning they will bake in the sun, day in and day out. I just finished fine tuning, and the basic idea is to completely plug the cavity around the muffler tip. Very easy to see the cavity when you remove the rear diffuser, and as long as there is no opening for the sound waves to enter inside the cavity and resonate all the way through the chassy, you are golden.

I almost completely eliminated the low frequencies entering the cabin, just enough left to tell you that the exhaust is not stock and then when I rev above 2K, the growl comes out, really great stuff, lots of work, in terms of taking the rear diffuser off about 10 times to methodically plug holes, but the idea is simple, the cavity right above the muffler is whats letting the sound/vibration/rasp inside the cabin.
Appreciate 0
      09-03-2015, 06:03 AM   #13
DanHazelrigg
Private
9
Rep
86
Posts

Drives: 2014 328i MSport EBII
Join Date: Apr 2012
Location: Warsaw/Fort Wayne, IN

iTrader: (1)

Great stuff! Thanks for my weekend project!
Appreciate 0
      06-17-2016, 12:11 PM   #14
dantheman1243
New Member
3
Rep
15
Posts

Drives: 2011 F10 535i
Join Date: Apr 2016
Location: Northport, NY

iTrader: (0)

How much of the 18 square feet did you end up using to over that area? Is 18 square feet more than enough? I have two cars I need to do this to.

- Dan
Appreciate 0
      06-21-2016, 04:29 AM   #15
tc328
Lieutenant
329
Rep
532
Posts

Drives: 328
Join Date: Apr 2007
Location: bstny

iTrader: (3)

Garage List
2007 3  [0.00]
Hmm have to try this
Appreciate 0
      02-09-2018, 03:12 PM   #16
aps
Lieutenant
aps's Avatar
107
Rep
528
Posts

Drives: '13 F30 335i - '14 F25 X3 x35i
Join Date: Apr 2016
Location: Los Angeles

iTrader: (3)

bumping an old thread as i'm attempting this mini project this weekend. i don't have much drone, but if I can tune out the little bit i get around 2k, i will be really happy.

I have some really old dynamat thats been laying in a box for a couple years. hopefully still good.
Appreciate 0
      02-09-2018, 03:29 PM   #17
alohasurftoad
Lieutenant Colonel
United_States
749
Rep
1,750
Posts

Drives: 428i gran coupe
Join Date: Apr 2015
Location: hawaii

iTrader: (0)

my dinan axle back has drone. i tried some sound deadening foam(not dynamat) in the surrounding area. didn't work at all, i didn't really expect it to work but i wanted to see if there was any noticeable reduction.

it seems like the actual twin pipes have some resonant frequencies like a speaker port. probably a different length pipes or wrapping the pipes to prevent it from vibrating would work better however i'm done with trying to fix it.
Appreciate 0
      11-23-2018, 02:32 PM   #18
hmmwvj
Enlisted Member
1
Rep
45
Posts

Drives: F30N 320i
Join Date: Aug 2017
Location: Malaysia

iTrader: (0)

Quote:
Originally Posted by Piggieback View Post
For anyone who installed AA or other aftermarket exhaust systems, even with straight pipe, you all should be familiar with the drone associated with 2-3k rpm. Very easy and cheap way to fix the problem, purchase dynamat/aftermatket sound deadening, and you can actually fine tune the amount of sound feedback in the cabin, but most notably, this eliminates those low frequencies that basically vibrate the cabin. I used these, and they worked like a charm, only needed 3 pieces, very easy to cut.

http://www.ebay.com/itm/251811573432...%3AMEBIDX%3AIT
Hi OP, how is this project holding up?
Appreciate 0
      11-26-2018, 09:59 AM   #19
mallorca328
Private First Class
Spain
40
Rep
101
Posts

Drives: F30 328i
Join Date: Aug 2018
Location: Spain

iTrader: (0)

Garage List
2012 F30 328i  [0.00]
i had drone after installing my remus...

it was so annoying that when i was driving i was thinking 100% on the drone all the time... it was my first exhaust and it was a horrible experience, i even put it up for sale right after a couple of days because i couldnt get a refund after using it

5 or 6 weeks later either the sound changed or i got used to it and doesnt bother me anymore, i dont even think about it when normal driving so im keeping it.. im really enjoying it now when i drive for fun

maybe give it some time? the interior of the new exhaust needs heat for some time, then the sound changes slightly for the final result, my mechanic told me to give it a minimum of 1000 kilometers, i needed about 1500 or 2000

ive read stories of people who skip this process and before installing it they put gasoline inside and set it on fire

Last edited by mallorca328; 11-26-2018 at 10:07 AM.
Appreciate 0
      11-26-2018, 10:46 AM   #20
CandyRedRC46
Second Lieutenant
CandyRedRC46's Avatar
82
Rep
202
Posts

Drives: 2013 328i
Join Date: Feb 2018
Location: Florida

iTrader: (0)

Are all you guys that are complaining about drone, without resonators? I have a catless AFE downpipe (2.25" bottleneck removed), supersprint front pipe with 3" straight pipe to the factory resonator and a Dinan axle back. My exhaust is almost too quiet lol. You can tell its catless on the cold start and when lugging the engine hard, but it sounds pretty much stock while cruising and not much louder than stock while getting on it as engine speed increases.
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 08:30 PM.




f30post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
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