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 > Engine / Drivetrain / Exhaust / Bolt-ons / Tuning

Post Reply
 
Thread Tools Search this Thread
      07-24-2013, 02:35 AM   #1
swamp2
Lieutenant General
swamp2's Avatar
United_States
643
Rep
10,404
Posts

Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

iTrader: (3)

Lightbulb BMW M3/M4 s55 Engine RPM Redline Projections via Technical Sound Analysis

BIMMERPOST
     Featured on BIMMERPOST.com
Quote:
Originally Posted by ProbyOne View Post



Check out the video at 3:07

1. Try to match the frequency of the observed sound which I estimate is around 350 Hz.

2. Figure out the speed of the car away from camera. It sounds like the top of 3rd gear which should be around 90-100 mph depending on gearing.

3. Correct for Doppler effect. Easy if you can Google. http://www.wolframalpha.com/input/?i...400Hz%2C+90mph

So again, it sounds pretty close to 8000 rpm. It's way better than a guess.
Fantastic idea! Taking your lead I dove in head first.

I began testing a couple of dyno recordings and fairly quickly found an E92 M3 video and V12 Aston with 6800 rpm redline. I recorded the sounds (just from crappy Youtube videos) and then did a Fourier transform to get the spectral content. E92 M3 frequency peak at redline should be 560 Hz, I measured 570 Hz. V12 Aston is 680 Hz theoretical, 688 observed. In both cases "the" peak was actually the second peak not the first. Those results are within about 2%. The method absolutely can work.

Moving on the the M4 video I'm not entirely sure that around the 3:07 time mark he get's a true redline shift. I think this is at Galgenkopf, what do you think? Based on that he is indeed most likely in 3rd and I agree that the peak speed at redline should be around 90-97 mph (depending both on gearing and redline). Getting a true discernible peak in the spectral results was not straight forward as compared to the dyno runs (to be expected) and thus my results are a range of frequencies from 345-365 Hz. The capture below from ~5.5-6.0 seconds is showing a discernible (first) peak at 358 Hz. Combining that with the Doppler effect from 90-97 mph gives a source frequency in the range of about 385 - 415 Hz. That in turn translates to 7700-8300 rpm! This is entirely consistent with my prior estimate of a peak redline of 7700 rpm.

UPDATE 7/26: Thanks to some additional insights from post below by bradleyland I am revising my final rpm estimate down considerably to 7250-7550 rpm. In short my audio capture was too low in quality. I did recheck a couple cases of dynos mentioned above using the new technique. For instance the V12 Aston came in at 6770 vs. 6800 quoted, less than 0.5% difference.

Given the F10 M5s redline in particular, 7200 rpm, I just don't think 8000 (Admin edit: rumor is close to 8000 rpm) is possible. There is also the prior problem of resolving the inconsistency of an 8000 rpm redline, about 400 ft lb of torque and about the same power as the existing M3...

To be more accurate and more certain we need a video of a clear redline shift with good audio quality and minimal Doppler (i.e. camera right by shift point). Anyone?
Attached Images
  
__________________
E92 M3 | Space Gray on Fox Red | M-DCT | CF Roof | RAC RG63 Wheels | Brembo 380mm BBK |
| Vorsteiner Ti Exhaust | Matte Black Grilles/Side Gills/Rear Emblem/Mirrors |
| Alekshop Back up Camera | GP Thunders | BMW Aluminum Pedals | Elite Angels |
| XPEL Full Front Wrap | Hardwired V1 | Interior Xenon Light Kit |

Last edited by swamp2; 07-26-2013 at 08:55 PM..
Appreciate 0
      07-24-2013, 07:06 AM   #2
neo871
Major
neo871's Avatar
Romania
144
Rep
1,399
Posts

Drives: 340i xDrive MPPSK
Join Date: Jul 2005
Location: Bucharest, Romania

iTrader: (0)

Thumbs up M3/M4 s55 Engine Redline Projections from Technical Sound Analysis

Quote:
Originally Posted by swamp2 View Post
Fantastic idea! Taking your lead I dove in head first.

...
This is impressive! What do you actually do for a living?
Appreciate 0
      07-24-2013, 08:12 AM   #3
CanAutM3
General
CanAutM3's Avatar
Canada
21170
Rep
20,754
Posts

Drives: 2021 911 turbo
Join Date: Jan 2012
Location: Montreal

iTrader: (1)

Garage List
Quote:
Originally Posted by swamp2 View Post
Fantastic idea! Taking your lead I dove in head first.

...

Great work, as usual Swamp .

Now we only need a clean vid to remove some of the variability
Appreciate 0
      07-24-2013, 08:26 AM   #4
mkoesel
Moderator
United_States
7544
Rep
19,368
Posts

Drives: No BMW for now
Join Date: Jun 2006
Location: Canton, MI

iTrader: (1)

Swamp, if you were my professor I would love your lectures but loathe your exams. That's very impressive work - gotta give props to both you and the guy that suggested the idea. I'll be even more impressed if your numbers match the production engine.

I wonder if the engine sounds from development-M5 track footage consistently yield 7200RPM. It would be an example (or examples) that are close to home.
Appreciate 0
      07-24-2013, 12:02 PM   #5
swamp2
Lieutenant General
swamp2's Avatar
United_States
643
Rep
10,404
Posts

Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

iTrader: (3)

Quote:
Originally Posted by mkoesel View Post
Swamp, if you were my professor I would love your lectures but loathe your exams. That's very impressive work - gotta give props to both you and the guy that suggested the idea. I'll be even more impressed if your numbers match the production engine.

I wonder if the engine sounds from development-M5 track footage condisently yield 7200RPM. It would be an example (or examples) that are close to home.
Thanks. I wanted to do some more work using actual track clips but did not have the chance. If you can suggest a good, clear redline occurrence for the F10 M5 I would be happy to repeat the analysis. It very quick to do actually, the software does everything.
__________________
E92 M3 | Space Gray on Fox Red | M-DCT | CF Roof | RAC RG63 Wheels | Brembo 380mm BBK |
| Vorsteiner Ti Exhaust | Matte Black Grilles/Side Gills/Rear Emblem/Mirrors |
| Alekshop Back up Camera | GP Thunders | BMW Aluminum Pedals | Elite Angels |
| XPEL Full Front Wrap | Hardwired V1 | Interior Xenon Light Kit |
Appreciate 0
      07-24-2013, 09:03 PM   #6
duk
///M
United_States
176
Rep
3,191
Posts

Drives: 2011 AW/FR 6MT E92
Join Date: Jun 2007
Location: Irvine, CA

iTrader: (0)

if it's 8k redline omggg take my monies? lol
__________________
2011.5 AW/FR E92 M3 6MT
Appreciate 0
      07-24-2013, 09:23 PM   #7
chmura
Colonel
chmura's Avatar
1571
Rep
2,509
Posts

Drives: 2019 M2 Competition
Join Date: Aug 2009
Location: Orange County, California

iTrader: (1)

I agree making this engine have a 8k redline will make it closer to true M engine.
Appreciate 0
      07-24-2013, 09:45 PM   #8
Mangler
First Lieutenant
Mangler's Avatar
17
Rep
329
Posts

Drives: 08' 335i, ZHP 330i
Join Date: Nov 2008
Location: Southeast

iTrader: (0)

Garage List
88 .  [0.00]
2008 BMW 335i  [0.00]
I have a go pro video from the front number of the new m6 driven to redline on a track if it would help.

T
Appreciate 0
      07-25-2013, 03:07 AM   #9
swamp2
Lieutenant General
swamp2's Avatar
United_States
643
Rep
10,404
Posts

Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

iTrader: (3)

Quote:
Originally Posted by Mangler View Post
I have a go pro video from the front number of the new m6 driven to redline on a track if it would help.

T
Thanks, might be fine to try but I'd prefer something a bit closer to a spectator filmed one like the video the analysis is based on.
__________________
E92 M3 | Space Gray on Fox Red | M-DCT | CF Roof | RAC RG63 Wheels | Brembo 380mm BBK |
| Vorsteiner Ti Exhaust | Matte Black Grilles/Side Gills/Rear Emblem/Mirrors |
| Alekshop Back up Camera | GP Thunders | BMW Aluminum Pedals | Elite Angels |
| XPEL Full Front Wrap | Hardwired V1 | Interior Xenon Light Kit |
Appreciate 0
      07-25-2013, 03:08 AM   #10
swamp2
Lieutenant General
swamp2's Avatar
United_States
643
Rep
10,404
Posts

Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

iTrader: (3)

Quote:
Originally Posted by neo871 View Post
This is impressive! What do you actually do for a living?
I'm a recovering physicist and recovering engineer. Now I sell engineering software.
__________________
E92 M3 | Space Gray on Fox Red | M-DCT | CF Roof | RAC RG63 Wheels | Brembo 380mm BBK |
| Vorsteiner Ti Exhaust | Matte Black Grilles/Side Gills/Rear Emblem/Mirrors |
| Alekshop Back up Camera | GP Thunders | BMW Aluminum Pedals | Elite Angels |
| XPEL Full Front Wrap | Hardwired V1 | Interior Xenon Light Kit |
Appreciate 0
      07-25-2013, 01:02 PM   #11
aajami
Brigadier General
aajami's Avatar
United_States
436
Rep
4,567
Posts

Drives: Space Gray '09 E92 M3
Join Date: Dec 2008
Location: Manhattan Beach, CA

iTrader: (4)

Big props to you Swamp. I'll be curious to see how accurate your projections are once the car is officially unveiled.
__________________
'09 E92 M3: Space Gray, Black, Carbon Leather | ZTP 2MK ZPP 2MT 6FL | link 1 / link 2
Mods: M Performance exhaust | ZCP retrofit | Euro airbox | GTS DCT flash | JPN 240 ECU flash | Euro LCI taillights | CRT lip | OEM alarm retrofit | Space Gray bumper plugs | BMW Performance: Mk. II spoiler / Mk. II non-electronic steering wheel / mirror caps / front grilles / side gills / intake louvers / emblem
Appreciate 0
      07-25-2013, 01:56 PM   #12
Brosef
Brigadier General
Brosef's Avatar
915
Rep
3,468
Posts

Drives: e92 M3
Join Date: Aug 2009
Location: Chicago

iTrader: (4)

this is why I read Bimmerpost. awesome analysis as always.
Appreciate 0
      07-25-2013, 02:08 PM   #13
kyleb350
Brigadier General
kyleb350's Avatar
United_States
429
Rep
4,709
Posts

Drives: '21 X3MC
Join Date: Jun 2008
Location: Milwaukee

iTrader: (6)

I'm no expert in this field, but aren't there still a number of unknowns you'd need to know before making these calculations? I see you make an estimate on speed, but wouldn't gearing and exhaust acoustics also come into play? Also, it's probably a safe assumption, but still an assumption that the car is shifting at redline.

Excellent analysis though.
Appreciate 0
      07-25-2013, 02:53 PM   #14
Ryan@IND
Ryan@IND's Avatar
United_States
1815
Rep
7,665
Posts

Drives: ACR
Join Date: Mar 2008
Location: Chicago

iTrader: (18)

Wow! Great work. Look forward to seeing the comparison between your analysis on the production S55.
__________________
IND DISTRIBUTION | 866-963-4520 • INSTAGRAMFACEBOOKFLICKR
Appreciate 0
      07-25-2013, 03:03 PM   #15
m5 guy
Brigadier General
m5 guy's Avatar
United_States
1799
Rep
3,213
Posts

Drives: 2020 M5 Comp
Join Date: Apr 2012
Location: Hawaii

iTrader: (14)

Great job!
__________________
2020 F90 M5 Comp Oxford Green Metallic II-Aragon JOURNAL
2016 F10 M5 Space Gray-Black SOLD
2012 E70 X5M Monte Carlo Blue-Silverstone SOLD
2001 E46 M3 Oxford Green Metallic II-Cinnamon SOLD
Appreciate 0
      07-25-2013, 03:25 PM   #16
///Matthew
Major
///Matthew's Avatar
202
Rep
1,231
Posts

Drives: 2013 M3, 1999 M3
Join Date: Dec 2010
Location: NJ

iTrader: (3)

Very impressive! Thank you!
__________________

2013 Santorini Blue M3
1999 Estoril Blue M3
mfatuation.com
Appreciate 0
      07-25-2013, 03:30 PM   #17
e1000
that's what SHE said!
75
Rep
1,163
Posts

Drives: 2011 E92 M3 ZCP
Join Date: Jun 2010
Location: OC

iTrader: (1)

Quote:
Originally Posted by neo871 View Post
This is impressive! What do you actually do for a living?
He stayed at a Holiday Inn Express last night
__________________
Appreciate 0
      07-25-2013, 03:31 PM   #18
Blindside_137
Lieutenant General
Blindside_137's Avatar
United_States
7047
Rep
10,691
Posts

Drives: 2011.75 SSII E90 M3 ZCP
Join Date: Jun 2010
Location: Raleigh, NC

iTrader: (2)

Doppler effect is one of my favorite physics topics, explaining so much in the real world.

Cool stuff!!
Appreciate 0
      07-25-2013, 03:45 PM   #19
ChrisK
Major General
ChrisK's Avatar
United_States
4474
Rep
7,589
Posts

Drives: '19 M2C
Join Date: Jun 2007
Location: Chicagoland

iTrader: (7)

Garage List
Quote:
Originally Posted by e1000 View Post
He stayed at a Holiday Inn Express last night
Dang-it you beat me toooo it!
__________________
www.ReTuneTheDeTune.com
2019 M2 Competition (Sunset Orange)
Appreciate 0
      07-25-2013, 03:55 PM   #20
solstice
Major General
5514
Rep
7,078
Posts

Drives: 2015 M3 6MT
Join Date: May 2013
Location: Seattle

iTrader: (0)

Nice!

Here's a pretty clean audio of the only production I6 turbo M car, it's in cabin but it would be interresting to see what top rpm the SW spits out.

4:24 and 4:28 for example seems like possible redline shifts.
( if you watch the whole thing you will also see two M3s showing who the daddy is )


Last edited by solstice; 07-25-2013 at 04:00 PM..
Appreciate 0
      07-25-2013, 03:58 PM   #21
bimmerjph
Colonel
bimmerjph's Avatar
United_States
123
Rep
2,024
Posts

Drives: 2005 Z4 3.0
Join Date: Oct 2011
Location: Tennessee

iTrader: (0)

That is actually quite impressive.

Good work!
Appreciate 0
      07-25-2013, 03:58 PM   #22
positiveions
Lieutenant General
positiveions's Avatar
Lebanon
978
Rep
11,725
Posts

Drives: 19 Tacoma, 16 Golf wagon
Join Date: Sep 2007
Location: Upland, CA

iTrader: (2)

Garage List
I want to say ,realistically, it's more like 7500 rpm.
Appreciate 0
Post Reply

Bookmarks

Tags
2014 bmw m3, 2014 m3, 2014 m3 forum, 2015 bmw m3, 2015 bmw m4, 2015 m3, 2015 m4, bmw f80, bmw f80 forum, bmw f80 forums, bmw f80 m3, bmw f80 m3 sedan, bmw f82, bmw f82 forum, bmw f82 forums, bmw f82 m3, bmw f82 m3 coupe, bmw f82 m3 forum, bmw f82 m4, bmw f82 m4 coupe, bmw f83, bmw f83 m3, bmw f83 m4, bmw m forum, bmw m forums, bmw m4, bmw m4 coupe, bmw m4 coupe forum, bmw m4 forum, bmw m4 forums, f80, f80 forum, f80 forums, f80 m3, f80 m3 forum, f80 m3 forums, f80 m3 sedan, f82, f82 coupe, f82 forum, f82 forums, f82 m3, f82 m3 coupe, f82 m3 forum, f82 m4, f82 m4 coupe, f82 m4 forum, f82 m4 forums, f83 m3, f83 m4, m forum, m forums, m3 f80, m3 f80 forum, m3 f80 forums, m4 forum, m4 forums

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 03:56 AM.




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