BMW X5 and X6 Forum 2014-Current
BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Post Reply
 
Thread Tools Search this Thread
      09-07-2017, 10:23 PM   #1
Nuckle
Captain
2186
Rep
600
Posts

Drives: 2023 Defender X
Join Date: Aug 2017
Location: Birmingham, AL

iTrader: (0)

What exactly is happening to make that wonderful sound these cars make at a high RPM gear change. I described it in another post as braaaap pow. Is it all for show or is there more to it? I know the AMG motors do it as well. Probably a newb question but it is a new sound to me.
Appreciate 0
      09-08-2017, 03:24 AM   #2
Alberta
Lieutenant Colonel
Alberta's Avatar
1977
Rep
1,826
Posts

Drives: F90
Join Date: Aug 2015
Location: somewhere

iTrader: (0)

Isn't it a question of gaz that isn't burned or something like this ?
Appreciate 0
      09-08-2017, 06:59 AM   #3
AwesomeM3
Colonel
AwesomeM3's Avatar
United_States
1635
Rep
2,773
Posts

Drives: F95 X5MC
Join Date: Oct 2007
Location: New Jersey

iTrader: (0)

Garage List
2015 BMW X5 M  [10.00]
2020 BMW X5M Compet ...  [0.00]
2008 M3  [10.00]
Quote:
Originally Posted by Can-am View Post
Isn't it a question of gaz that isn't burned or something like this ?
I think he is referring to the farting sound coming from the exhaust when in Sport or Sport+, and the shifts are aggressive.
__________________
2020 F95 X5///M Competition CarBahn Autoworks Stage 1 | 2023 Lamborghini Huracan Tecnica
Appreciate 0
      09-08-2017, 07:54 AM   #4
Nuckle
Captain
2186
Rep
600
Posts

Drives: 2023 Defender X
Join Date: Aug 2017
Location: Birmingham, AL

iTrader: (0)

Quote:
Originally Posted by AwesomeM3 View Post
I think he is referring to the farting sound coming from the exhaust when in Sport or Sport+, and the shifts are aggressive.
Yes, the farting sound. What is it?
Appreciate 0
      09-08-2017, 09:07 AM   #5
iconoclast
Self-Deprecating Narcissist
iconoclast's Avatar
No_Country
7258
Rep
6,561
Posts

Drives: Audi BMW Ferrari LR MB
Join Date: Jan 2014
Location: In, Out & Around...

iTrader: (1)

turbulence in the exhaust created by cooled air and hot air meeting and cooling off as it travels down the exhaust pipes. when they equalize you get the sound you are referring to. while not a proper analogy it may help to think about thunder which occurs after lightning.
Appreciate 1
AwesomeM31634.50
      09-08-2017, 10:07 AM   #6
aas5
Captain
171
Rep
901
Posts

Drives: 2022 Tesla Model 3
Join Date: Mar 2010
Location: NY

iTrader: (0)

Quote:
Originally Posted by iconoclast View Post
turbulence in the exhaust created by cooled air and hot air meeting and cooling off as it travels down the exhaust pipes. when they equalize you get the sound you are referring to. while not a proper analogy it may help to think about thunder which occurs after lightning.
But what causes there to be no sound in comfort?
__________________
Sold: 2020 X7 M50 White Mineral with Ivory & Blue, 2017 X6M Long Beach Blue with Mugello Red, 2014 X6M Monte Carlo Blue with Mugello Red, 2011 X6 5.0 Black on Black, 2008 E350 4Matic Silver, 2006 Infiniti M45 Diamond Graphite
Appreciate 0
      09-08-2017, 12:26 PM   #7
iconoclast
Self-Deprecating Narcissist
iconoclast's Avatar
No_Country
7258
Rep
6,561
Posts

Drives: Audi BMW Ferrari LR MB
Join Date: Jan 2014
Location: In, Out & Around...

iTrader: (1)

valves close. less turbulence and less air to pass through. they're still there but not as loud.
Appreciate 0
      09-09-2017, 01:23 AM   #8
Nuckle
Captain
2186
Rep
600
Posts

Drives: 2023 Defender X
Join Date: Aug 2017
Location: Birmingham, AL

iTrader: (0)

I guess I should have asked if the sound was necessary? Is it something forced to happen or does it need to happen?
Appreciate 0
      09-11-2017, 08:46 AM   #9
ShockArrival
Lieutenant
ShockArrival's Avatar
United_States
496
Rep
494
Posts

Drives: G80 Search
Join Date: Sep 2017
Location: STL

iTrader: (0)

Garage List
2014 BMW M5  [0.00]
Isn't "BRAAAAP-POW" the sound made when Batman power-shifts?

Appreciate 0
      09-13-2017, 02:02 PM   #10
Roundown
Colonel
576
Rep
2,353
Posts

Drives: BMW
Join Date: Jan 2012
Location: New England

iTrader: (0)

Quote:
Originally Posted by iconoclast View Post
valves close. less turbulence and less air to pass through. they're still there but not as loud.
This is correct, would add that comfort down shifts less aggressively so the changes in engine speed/air speed are less violent/loud.
Appreciate 1
iconoclast7257.50
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 06:23 AM.




xbimmers
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