02-28-2018, 11:36 AM | #45 | |
New Member
32
Rep 24
Posts |
Quote:
|
|
Appreciate
0
|
02-28-2018, 12:33 PM | #46 |
Major General
5865
Rep 6,637
Posts |
Oh that's not true here, at least as far as burbles and pops and bangs. For whatever reason the overrun is more extreme in MDM mode on the M2 on the MT or the DCT in sequential.
|
Appreciate
0
|
02-28-2018, 12:35 PM | #47 | |
Brigadier General
2464
Rep 3,803
Posts |
Quote:
We just picked up an M2 this morning... I'm excited to experience it. Should be sweet. |
|
02-28-2018, 12:40 PM | #48 |
Major General
5865
Rep 6,637
Posts |
I saw, it's MG. Congratulations! Looks bad ass! I noticed you have black kidney grille and side gills already. You can get orange side reflector deletes from Ind to complete the look!
|
Appreciate
1
Who's on first2464.00 |
02-28-2018, 01:39 PM | #49 | |
Brigadier General
2464
Rep 3,803
Posts |
Quote:
The M2 will be properly updated (that's my M4 also next to it). So, I'm fully informed about IND, etc.... |
|
Appreciate
0
|
02-28-2018, 01:42 PM | #50 |
Major General
5865
Rep 6,637
Posts |
|
Appreciate
0
|
02-28-2018, 01:44 PM | #51 |
Brigadier General
2464
Rep 3,803
Posts |
|
Appreciate
0
|
02-28-2018, 03:21 PM | #52 |
Private First Class
92
Rep 177
Posts
Drives: Long Beach Blue M2
Join Date: Aug 2017
Location: Puerto Rico
|
|
Appreciate
0
|
02-28-2018, 03:26 PM | #53 | |
Captain
504
Rep 780
Posts |
Quote:
|
|
Appreciate
0
|
02-28-2018, 06:37 PM | #54 | |
Lieutenant Colonel
683
Rep 1,608
Posts |
Quote:
I have a decibel meter, so I will try and record. However, remember, at standstill, if you hold a throttle position, and switch from comfort to sport, the rpms will rise slightly because of aggressive throttle mapping, which will be recorded as increased sound.. But I dont think this is what we're talking about.
__________________
Boostm3
'18 LBB MT M2 Exec pkg, Moonroof, Production 7/6/17 |
|
Appreciate
0
|
02-28-2018, 10:50 PM | #55 | |
Private First Class
92
Rep 177
Posts
Drives: Long Beach Blue M2
Join Date: Aug 2017
Location: Puerto Rico
|
Quote:
Take the car, in comfort mode, blip the throttle up to 3k or just pick a spot above 1.5k. Just a blip, no need to hold it there, and record the waveform or just use your ears... Do the same in Sport+ or Traction mode... You can't tell me there is no difference. One is just the engine growl and whine back to idle, the other sounds like a thunderclap. It may be the same decibels, but it's not the same sound. And that sound can be heard from outside the cabin, so there is zero chance that the ASD is doing all that work. Unless the M2 has some hidden external speakers, which I doubt. That thunderclap sound, that was like half the reason to buy the car for me. And I saw no other car that sounds even remotely like that. That's my perspective. I could try recording the different waveforms and posting them, but honestly, the difference ain't subtle. It doesn't take that level of scrutiny to hear it. |
|
Appreciate
1
mtoosexy730.00 |
02-28-2018, 11:21 PM | #56 | |
Lieutenant Colonel
683
Rep 1,608
Posts |
Quote:
__________________
Boostm3
'18 LBB MT M2 Exec pkg, Moonroof, Production 7/6/17 |
|
Appreciate
1
sh_kross91.50 |
03-01-2018, 10:03 AM | #57 | |
Private First Class
190
Rep 195
Posts |
Quote:
Doubling of the volume (perception) should be sensed as a level difference of +10 dB. Doubling the sound pressure (amplitude) corresponds to a measured level change of +6 dB. Doubling of sound intensity (acoustic energy) belongs to a calculated level change of +3 dB. In the case of your measured observations, you are looking at a nearly 2x perceived volume change at idle. I would love to do this test with my completely stock 2016 M2 and see if my measured results match yours in the change in sound pressure level. I have Noise dosimeter at work that I may be able to borrow to take some measurements. |
|
Appreciate
2
Threeebowel31.50 Aloha Joe393.00 |
03-01-2018, 02:22 PM | #58 | |
Hanapaa!
393
Rep 449
Posts |
Quote:
1st pic is of my Ipad location in regards to the test this morning. Please forgive the mess in the background as that's my recycle storage area. I tried to spruce it up with my ED plate and a friends autobahn plate. 2 & 3 are in comfort mode in idle. 4 & 5 are in sport in idle. My readings for both, are a little lower than my very first test day 4 days ago. This is probably due to the location of the Ipad, but the difference in results remain basically the same. So if I understand correctly, in my pictures, the difference in the two modes has a much greater difference than the 8-9 percent that I originally thought? Or am I not reading these charts correctly? |
|
Appreciate
1
LinkF1189.50 |
03-01-2018, 03:56 PM | #59 |
Private First Class
190
Rep 195
Posts |
Thanks Joe, focused on human factors engineering with of my master's program, studied the perception of sound in detail. Given your readings at face value, there is a definite difference in the sound from the first two samples and the second two samples. The change in sound pressure level looks to be approximately 5 dB based on the algorithms in the app you downloaded. That means that an observer at the same distance from your exhaust as the microphone of the iPad would experience a 50% increase in loudness between the two modes.
However, there are some things I see from your pictures that may be affecting the results. 1. It appears that your exhaust is facing a wall which will do a very good job of reflecting the sound back towards the microphone amplifying the signal. In this case I would expect that you are getting higher raw numbers than you would with the exhaust facing out of the garage. 2. You seem to be on a concrete surface which again will do a very good job of transmitting the sound through the ground to the microphone in the iPad. I would expect that you would get lower raw numbers by completing the test on a soft surface such as dirt or grass. 3. The iPad microphone is likely obscured by the case that you have on the device. Even if it is not the microphone on devices such as the iPad are usually optimized for speech signals (2k to 4k Hz) and are likely providing higher amplitudes for those frequencies than exist in real life. Without using specialized equipment or a neutral, external microphone the results are likely to be inconsistent, as you see in your pictures. 4. If you change the distance of the microphone, you change the results significantly. Sound Pressure Level in an environment without reflection drops with the inverse of distance, but dB is logarithmic. So 80 db at 2 feet is expected to be 74 dB at 4 feet and 66 dB at 10 feet. |
Appreciate
1
Aloha Joe393.00 |
03-01-2018, 04:20 PM | #60 | |
Lieutenant Colonel
683
Rep 1,608
Posts |
Quote:
If there is a ~50% sound difference at the exhaust between drive modes, that is certainly a difference anyone could easily hear. So Im mystified why Joe has this phenomena, and others of us dont.
__________________
Boostm3
'18 LBB MT M2 Exec pkg, Moonroof, Production 7/6/17 |
|
Appreciate
1
Aloha Joe393.00 |
03-01-2018, 07:26 PM | #61 |
Captain
504
Rep 780
Posts |
Check this...
https://www.leib-engineering.de/F87-...control-unit_1 There are a couple of versions. This one deletes the ASD at the same time! I think this confirms Joe's readings. This changes the valve in any mode. Last edited by GregoryK; 03-01-2018 at 08:01 PM.. |
Appreciate
0
|
03-01-2018, 07:56 PM | #62 | |
Hanapaa!
393
Rep 449
Posts |
Quote:
My street is a fairly well used street, so I have the exhaust facing the wall instead of out of my garage to avoid, street, wind and other sounds from the equation. Here's what I think is the most interesting part of this whole exercise. In comfort mode, the app equates the M2 exhaust to loud singing and in sport mode, it's an automobile! Also when I did the cold start reading earlier, it called it a diesel truck! : |
|
Appreciate
0
|
03-01-2018, 07:59 PM | #63 | |
Lieutenant Colonel
683
Rep 1,608
Posts |
Quote:
__________________
Boostm3
'18 LBB MT M2 Exec pkg, Moonroof, Production 7/6/17 |
|
Appreciate
0
|
03-01-2018, 09:45 PM | #64 |
Captain
504
Rep 780
Posts |
I am simply saying that Joe's measurements are showing the difference between when the valve is closed and open. Simple - that seems to be the answer. There is a valve in the stock exhaust that opens and closes under certain conditions. This link shows that it is possible to override the stock behavior with this device. Joe does not have this device installed his car acts like it is supposed to.
__________________
"I would rather cry in a BMW than smile on a bicycle." Ma Nuo |
Appreciate
0
|
03-01-2018, 10:26 PM | #65 |
Lieutenant Colonel
683
Rep 1,608
Posts |
Look what I found.... Guess I just havent experienced it yet. Whenever it occurs, it must be a lot quieter than that obnoxious ASD since I had absolutely no trouble hearing that annoying noise before I got rid of it.
http://www.bimmerfile.com/2016/02/22...ng-the-bmw-m2/ "After our drive on the track and around Monterey I can confirm that the sound of the exhaust is both more aggressive and full sounding than the M235i. The exhaust flap is closed at idle, in the lower speed range and nearly of the time when the car’s in COMFORT mode (the exception being under heavy load). In SPORT and SPORT+ positions, the exhaust flap is fully open when the engine is idling while the vehicle is stationary and in the lower gears. Interestingly in the the higher gears, the exhaust flap is closed in the critical ranges. The same applies in the upper engine speed ranges depending on the load. "
__________________
Boostm3
'18 LBB MT M2 Exec pkg, Moonroof, Production 7/6/17 |
Appreciate
0
|
03-01-2018, 10:53 PM | #66 | |
Hanapaa!
393
Rep 449
Posts |
Quote:
Shortly after the 1,200 mile service, I had the Fabspeed d/p installed. I then coded out ASD, so ASD was always on prior to the d/p install. I don’t recall noticing a sound difference when everything was stock but that may have been due to ASD. My office building parking is 4 stories high and covered. Also when going up between each floor, the walls on the sides are high. Driving up my parking lot after d/p and coding, with the drivers side window down, is the first I can remember a sound difference between comfort & sport. It’s clearly audible here. While technically, it could be a 50% increase in sound. My ears tell me that it’s not that loud. So to answer your d/p question, I believe that it makes it more noticeable. |
|
Appreciate
0
|
Post Reply |
Bookmarks |
|
|