BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read




 

Post Reply
 
Thread Tools Search this Thread
      10-19-2011, 09:46 PM   #133
1M Fan
SMSgt
11
Rep
239
Posts

Drives: AW 1M Coupe
Join Date: Dec 2010
Location: USA, TN

iTrader: (0)

Garage List
1012 F150  [0.00]
1971 Chevrolet Nova  [0.00]
2011 1M  [0.00]
Quote:
Originally Posted by rapter View Post
What were to conditions that you posted that there was no drone at all? How could the drone come back after the "overkill" was put in, maybe you were not driving it on load (note: it will only drone on load).
In my car it comes and goes. I can nudge the gas a little and it will go away. It will stay away and then come back. Other times, It is always there and sometimes in never happens. It is very inconsistent. Every test drive is at least 20 miles to warm it up, then see if it will drone or not.
Appreciate 0
      10-20-2011, 06:45 PM   #134
rapter
Lieutenant
70
Rep
485
Posts

Drives: 1(M)other f*^#er of a car
Join Date: Nov 2010
Location: Canada

iTrader: (0)

Quote:
Originally Posted by 1M Fan View Post
In my car it comes and goes. I can nudge the gas a little and it will go away. It will stay away and then come back. Other times, It is always there and sometimes in never happens. It is very inconsistent. Every test drive is at least 20 miles to warm it up, then see if it will drone or not.
Wow! I would see that your dealer would be able to help with that as it is on/off.

Mine I just on all the time.
Appreciate 0
      10-20-2011, 06:54 PM   #135
sparoz
Brigadier General
sparoz's Avatar
Australia
191
Rep
4,848
Posts

Drives: VO 1///M; Macan Turbo
Join Date: Jun 2008
Location: Sunshine Coast

iTrader: (0)

I was picking up the new X3 yesterday and the old Service Manager was back helping out as one of their staff is away (he was promoted ). Had a chat to him and he's going to test drove with me. He said as it is in every gear in the same rev range at the same load, it is more than likely to be the exhaust. He is going to loosen everything up, run the car and re tighten everything to see if it solves the problem as that often does. I will keep you guys posted.
__________________
Macan S Diesel - Carrera White
Macan Turbo - White
1///M - Valencia Orange
Appreciate 0
      10-25-2011, 09:46 AM   #136
Robcut1
Second Lieutenant
112
Rep
267
Posts

Drives: 2016 M4GTS
Join Date: Oct 2011
Location: Jupiter, Fl

iTrader: (1)

Any new ideas, thoughts, comments on how to reduce "drone"?
Appreciate 0
      10-25-2011, 11:31 AM   #137
T1T2GRE
CW2
T1T2GRE's Avatar
United_States
27
Rep
440
Posts

Drives: 1SMC - traded away
Join Date: Sep 2010
Location: Pennsylvania

iTrader: (1)

Garage List
2011 BMW 1M  [7.33]
So, for those of you who did the insulation in the trunk, did it also deaden the normal "nice" sound in the other gears? Or did it selectively delete the higher-gear drone issue? I was just wondering this morning if the nice tone we hear going through the gears will be muffled away with that fix.
__________________
Good-bye, ol' Paint...
Appreciate 0
      10-25-2011, 08:05 PM   #138
Rekraps
USMA 81
United_States
117
Rep
234
Posts

Drives: Own two 1M's, VO total OEM
Join Date: Aug 2011
Location: Atlanta

iTrader: (0)

Quote:
Originally Posted by T1T2GRE View Post
So, for those of you who did the insulation in the trunk, did it also deaden the normal "nice" sound in the other gears? Or did it selectively delete the higher-gear drone issue? I was just wondering this morning if the nice tone we hear going through the gears will be muffled away with that fix.
The drone is simple resonance, that is frequency matching caused by natural vibrations of the engine, exhause gas and exhaust pipes. I submit that a simple change in the diameter of the piping, more or less, will eliminate the drone. Aircraft designers, bridge builders and any other structure is always designed with resonance in mind. Eventually it will damage or destroy the integrity of the material to which it impacts. Tightening the pipes will not help, wrapping them will only hide or surpress the noise, in order to make it go away the actual resonance needs to be cancelled. Think about two waves joining in sync... they get bigger. Now those two same waves can also cancel each other out. That is what you want. So... the natural vibration frequency of the engine at the point you hear the drone, just happens to match that of the exhaust piping. You would have thought the M team would have considered normal cruising RPM and adjusted the piping size accordingly.
Appreciate 0
      10-25-2011, 08:08 PM   #139
1SerieStud
Brigadier General
1SerieStud's Avatar
183
Rep
3,939
Posts

Drives: '11 VO 1M (498 of 740)
Join Date: Jul 2010
Location: Jacksonville, FL

iTrader: (11)

Quote:
Originally Posted by Rekraps View Post
The drone is simple resonance, that is frequency matching caused by natural vibrations of the engine, exhause gas and exhaust pipes. I submit that a simple change in the diameter of the piping, more or less, will eliminate the drone. Aircraft designers, bridge builders and any other structure is always designed with resonance in mind. Eventually it will damage or destroy the integrity of the material to which it impacts. Tightening the pipes will not help, wrapping them will only hide or surpress the noise, in order to make it go away the actual resonance needs to be cancelled. Think about two waves joining in sync... they get bigger. Now those two same waves can also cancel each other out. That is what you want. So... the natural vibration frequency of the engine at the point you hear the drone, just happens to match that of the exhaust piping. You would have thought the M team would have considered normal cruising RPM and adjusted the piping size accordingly.
Nope. Changing the diameter of the pipe will simply move the resonance frequency.
Appreciate 0
      10-26-2011, 09:21 AM   #140
sparoz
Brigadier General
sparoz's Avatar
Australia
191
Rep
4,848
Posts

Drives: VO 1///M; Macan Turbo
Join Date: Jun 2008
Location: Sunshine Coast

iTrader: (0)

Quote:
Originally Posted by Rekraps View Post
The drone is simple resonance, that is frequency matching caused by natural vibrations of the engine, exhause gas and exhaust pipes. I submit that a simple change in the diameter of the piping, more or less, will eliminate the drone. Aircraft designers, bridge builders and any other structure is always designed with resonance in mind. Eventually it will damage or destroy the integrity of the material to which it impacts. Tightening the pipes will not help, wrapping them will only hide or surpress the noise, in order to make it go away the actual resonance needs to be cancelled. Think about two waves joining in sync... they get bigger. Now those two same waves can also cancel each other out. That is what you want. So... the natural vibration frequency of the engine at the point you hear the drone, just happens to match that of the exhaust piping. You would have thought the M team would have considered normal cruising RPM and adjusted the piping size accordingly.
Quote:
Originally Posted by 1SerieStud View Post
Nope. Changing the diameter of the pipe will simply move the resonance frequency.
I would think that's what he meant by eliminate - eliminate from cruising speed.

Unfortunately, they probably only have Germany's cruising speed in mind where there is no drone.
__________________
Macan S Diesel - Carrera White
Macan Turbo - White
1///M - Valencia Orange
Appreciate 0
      10-26-2011, 09:50 AM   #141
MusclezMarinara
Banned
United_States
262
Rep
5,018
Posts

Drives: VALNCYA
Join Date: Jan 2009
Location: Jersey

iTrader: (23)

Garage List
Reducing drone go get a 128i

I can hear what you guys are saying but its an ///M would you rather it be quiet SMH.
I Cant wait for an exhaust on mine
Appreciate 0
      10-26-2011, 11:17 AM   #142
mPlasticDesign
Major General
mPlasticDesign's Avatar
684
Rep
5,069
Posts

Drives: BMW 230i Msport w/LSD
Join Date: Nov 2007
Location: Astral Projecting: ∞ 23.516 -122 02.625 0242.101 ĕv'rē-hwâr'

iTrader: (16)

Garage List
Exclamation Hopefully DINAN has a solution in the works!

I posted this in the 'Drone Poll' thread and I thought I would added it here, hope this gives some insight to the designing/developing approach to drone:


Quote:
Originally Posted by Mr.Metak2you View Post
I think maybe this should have been established page1.

But DRONE is:

A continuous, low frequency, monotonous sound.

It doesn't even need to be loud, in fact it is usually under very light load in lower RPM's. Just read what DINAN engineers struggled with on the E9x M3 exhaust they were developing. They state: "We worked at designs that would maintain the dual exhaust outlets but each iteration resulted in a heavy, low frequency drone with far too much back-pressure to produce any substantial power gains." Yet some M3 owners scoffed at the DINAN exhaust because the outer pipes were faux. For me and many others who bought the DINAN exhaust, the real functional gains and the lack of drone was more important.

__________________
Appreciate 0
      10-26-2011, 12:29 PM   #143
hlmiii
Lieutenant
United_States
86
Rep
541
Posts

Drives: '11 1M '10 M5 '05 M3 '12 CRT
Join Date: Nov 2008
Location: Houston

iTrader: (1)

So we know what to work with, here ...
Quote:
Originally Posted by Rekraps View Post
The drone is simple resonance, that is frequency matching caused by natural vibrations of the engine, exhause gas and exhaust pipes.
Vibrations together with their environment. In free air vibration dissipates immediately in all directions, without restriction, whereas in other situations vibration is amplified by any nearby or attached hardware, especially enclosure(s).

Quote:
Originally Posted by Rekraps View Post
I submit that a simple change in the diameter of the piping, more or less, will eliminate the drone.
Not necessarily. It would merely alter it.

Quote:
Originally Posted by Rekraps View Post
Eventually it will damage or destroy the integrity of the material to which it impacts.
Only in extreme sympathetic (harmonic) situations.

Quote:
Originally Posted by Rekraps View Post
Tightening the pipes will not help, wrapping them will only hide or surpress the noise.
No. Damping/wrapping reduces amplitude, which results in reduced audibility. To the extent that the vibration is absorbed by the damping material and becomes heat, it is eliminated as noise.
By itself tightening the pipes might help, BTW, if it reduces amplitude (through making it more difficult for the materials to vibrate).

Quote:
Originally Posted by Rekraps View Post
In order to make it go away the actual resonance needs to be cancelled.
Not necessarily. Damping and/or other control is the most efficient technique.

Quote:
Originally Posted by Rekraps View Post
... cancel each other out. ... You would have thought the M team would have considered normal cruising RPM and adjusted the piping size accordingly.
To "cancel" vibration there would have to be a second vibration/resonance of the same frequency(s) and the same amplitude generated and then added exactly 180 degrees out of phase (by some additional hardware) in order to cancel the original resonance. Pretty costly and impractical.
Changing the size/materials/mounting/etc. is what controls the frequency of the resonance ("pitch") and amplitude ("volume").

TMI here, for sure.
Appreciate 0
      10-26-2011, 05:22 PM   #144
sparoz
Brigadier General
sparoz's Avatar
Australia
191
Rep
4,848
Posts

Drives: VO 1///M; Macan Turbo
Join Date: Jun 2008
Location: Sunshine Coast

iTrader: (0)

Quote:
Originally Posted by MusclezMarinara View Post
Reducing drone go get a 128i

I can hear what you guys are saying but its an ///M would you rather it be quiet SMH.
I Cant wait for an exhaust on mine
I rather it be louder. I also rather it had no drone.
__________________
Macan S Diesel - Carrera White
Macan Turbo - White
1///M - Valencia Orange
Appreciate 0
      10-31-2011, 09:45 AM   #145
johnsfb
Private
Scotland
15
Rep
81
Posts

Drives: 1M
Join Date: Feb 2010
Location: Scotland

iTrader: (0)

new exhaust

The drone completely gone.

I’ve had my new exhaust on the car for a while now and it has settled in and sounding a bit deeper than at first.

Maybe the best way to describe it is that it works the same way as the Akrapovic BMW X5M (mine is similar to the picture on their website) and probably the same as their 1M although I haven’t yet seen a picture of that.

The difference in mine is that the valves are actuated by the turbo boost and not electronically. This means that when you put your foot down a bit the valves open and the exhaust flow by-passes the back box and exits straight out through the outer two tips and the noise is brilliant. Normally the flow goes through the rear box and actually is slightly quieter than standard but certainly deeper with wuffles and pops.
The other difference in the system is the two secondary cats have been taken out and the centre silencer replaced by one slightly larger. Instead of a single pipe exit from this new centre box there’s now two pipes back to the rear. They said the size of this box is optional according to what noise levels you’re looking for.
This was made by BCS Automotive who are based in St Helens and the four hour drive down there from Perth was certainly worthwhile. They've got a video www.bcsautomotive.co.uk

My insurance people said ok and no extra premium and that was a surprise.
Dealer knows and not bothered.

So, relatively quiet when I want or WTF if I feel like it.
All this and no drone - happy me. Great outcome.

Last edited by johnsfb; 11-01-2011 at 05:13 AM..
Appreciate 0
      10-31-2011, 07:31 PM   #146
Robcut1
Second Lieutenant
112
Rep
267
Posts

Drives: 2016 M4GTS
Join Date: Oct 2011
Location: Jupiter, Fl

iTrader: (1)

I emailed BCS automotive but never got a response.
There is nothing to suggest their products are available in the US.
Appreciate 0
      12-01-2011, 08:28 AM   #147
Robcut1
Second Lieutenant
112
Rep
267
Posts

Drives: 2016 M4GTS
Join Date: Oct 2011
Location: Jupiter, Fl

iTrader: (1)

BCS automotive will sell direct to US customers at a very good price for now. Set up includes throttle controlled valve.
Eager to try out. Also they are testing with a GIAC engine tune.
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 01:30 PM.




1addicts
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