[Threeebowel]

Originally Posted by boostm3

I dont think so. The first link is referring to the pops and crackles on exhaust overrun which is definitely more pronounced in Sport+ mode and MDM. And the second link refers to valving wrt cold starts, and some other observations that dont prove much.

All I know is that since ASD delete, switching between drive modes makes no difference whatsoever on my M2. All this said with a ymmv proviso. Maybe its the downpipe Joe has; maybe its the coded vs harnessed ASD delete method which might have an influence on exhaust valving. Maybe its the model year of the M2. Im not doubting what he is hearing and measuring, and Im not doubting what Im hearing. There must be an explanation for the difference; I just dont know what it is at this point. The whole connection between ecu controlled exhaust valving and what exactly happens between drive modes is a bit of a mystery.

It strikes me that ALOHA JOE is reporting data and you're reporting perception. Is there a way you can measure your exhaust volume? Otherwise, all this debate is just noise on an internet car forum..

[akkando]

Originally Posted by Who's on first

MDM has nothing to do with anything except traction items.

Unless it's different then all the other M's. Which I doubt.

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.

[Who's on first]

Originally Posted by akkando

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.

Alrighty then.

We just picked up an M2 this morning... I'm excited to experience it. Should be sweet.

[akkando]

Originally Posted by Who's on first

Alrighty then.

We just picked up an M2 this morning... I'm excited to experience it. Should be sweet.

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!

[Who's on first]

Originally Posted by akkando

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!

Yea. Car came with them.

The M2 will be properly updated (that's my M4 also next to it).

So, I'm fully informed about IND, etc....

[akkando]

Originally Posted by Who's on first

Yea. Car came with them.

The M2 will be properly updated (that's my M4 also next to it).

So, I'm fully informed about IND, etc....

Looks like San Marino Blue? I really wish I could have gotten that on the M2.

[Who's on first]

Originally Posted by akkando

Looks like San Marino Blue? I really wish I could have gotten that on the M2.

Tanzanite

[sh_kross]

Originally Posted by Who's on first

Tanzanite

Ooh... that deep blue really suits the M4. You have any pictures?

[GregoryK]

Originally Posted by boostm3

I dont think so. The first link is referring to the pops and crackles on exhaust overrun which is definitely more pronounced in Sport+ mode and MDM. And the second link refers to valving wrt cold starts, and some other observations that dont prove much.

All I know is that since ASD delete, switching between drive modes makes no difference whatsoever on my M2. All this said with a ymmv proviso. Maybe its the downpipe Joe has; maybe its the coded vs harnessed ASD delete method which might have an influence on exhaust valving. Maybe its the model year of the M2. Im not doubting what he is hearing and measuring, and Im not doubting what Im hearing. There must be an explanation for the difference; I just dont know what it is at this point. The whole connection between ecu controlled exhaust valving and what exactly happens between drive modes is a bit of a mystery.

I might be missing something but the first link refers to a valve in the stock exhaust that makes out louder in certain conditions...

[boostm3]

Originally Posted by Threeebowel

It strikes me that ALOHA JOE is reporting data and you're reporting perception. Is there a way you can measure your exhaust volume? Otherwise, all this debate is just noise on an internet car forum..

This whole thing started when Joe reported he Heard a difference It started off being perceptual.. the fact is there are myriad posts on the ASD delete threads that corroborate what Im hearing, or rather, not hearing. The simple fact is, with ASD enabled, we hear a very obvious increase in cabin sound; with it disabled, we dont, and when we check the sound with windows down, we dont hear it either.

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.

[sh_kross]

Originally Posted by boostm3

This whole thing started when Joe reported he Heard a difference It started off being perceptual.. the fact is there are myriad posts on the ASD delete threads that corroborate what Im hearing, or rather, not hearing. The simple fact is, with ASD enabled, we hear a very obvious increase in cabin sound; with it disabled, we dont, and when we check the sound with windows down, we dont hear it either.

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.

The thing is, though, the real difference isn't in the volume or the pitch of the exhaust note. At least for me it isn't. I know what you mean by the throttle map, but that's not what I'm referring to.

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.

[boostm3]

Originally Posted by sh_kross

The thing is, though, the real difference isn't in the volume or the pitch of the exhaust note. At least for me it isn't. I know what you mean by the throttle map, but that's not what I'm referring to.

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.

Absolutely.. Snaps, Crackles, and Pops galore in Sport and even moreso in Sport+ mode, and MDM mode.. No disagreement there.. However I thought what was being referred to was something different. You know how with ASD enabled, you can affect the fake asd noise in the cabin simply by changing drive modes, even at idle. With asd deleted, you cant do that anymore, neither at idle nor under acceleration, thank goodness! BUT those wonderful snaps crackles and pops are produced legitimately from the exhaust under engine overrun conditions, and thats something very different which I wholeheartedly endorse.

[LinkF1]

Originally Posted by Aloha Joe

I’m not claiming that the valves are open, tux2005 brought that up. I posted earlier that I don’t know the technical explanation of why my exhaust is louder in sport than comfort, but it is and it’s not just opinion.

I re-did the db test with my ipad again today with very similar results as I posted earlier. On average, comfort mode was about 1 db closer to sport today versus Sunday’s test. The difference in the 1 db difference could be attributed to the location of my ipad not being in the exact location as Sunday.

Please keep in mind, my tests were done with the ipad approx 3 feet from the exhaust and just to the outside on the drivers side. The difference is literally only about 8-9% louder on my tests. It’s nowhere near the 30+ percent versus a cold start, so please don’t think it’s a drastic change.

Just to be clear, decibels are measured with a logarithmic scale, a 8-9% change in the raw number corresponds to a much larger change in perception of that sound. Decibels are a measure of sound pressure level and perceptions of sound pressure levels differ with each individual, however below there are three concepts that will help each of us communicate a little bit clearer on what we think we are experiencing.

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.

[Aloha Joe]

Originally Posted by LinkF1

Just to be clear, decibels are measured with a logarithmic scale, a 8-9% change in the raw number corresponds to a much larger change in perception of that sound. Decibels are a measure of sound pressure level and perceptions of sound pressure levels differ with each individual, however below there are three concepts that will help each of us communicate a little bit clearer on what we think we are experiencing.

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.

LinkF1, Thank you for the great information! It looks like you know your sounds, so hopefully you can assist me. I have attached some pics below of my Ipad and if you would be kind enough to help interpret them for me.

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?

[LinkF1]

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.

[boostm3]

Originally Posted by LinkF1

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.

Nevertheless, hes recording a differential of sound modes, whether or not the placement or the concrete, or the shape of the room is influencing. If sport mode records consistently higher than comfort, there must be something to it, especially if the recordings are done at the same rpm level such as at idle, or at a steady throttle setting.. That would have to be a controlled variable, as we know that higher rpms usually create more sound.. What is strange is that Ive spoken to a lot of people who have deleted their ASD and nobody Ive spoken with has heard this differential. I had thought, therefore, that ASD was the only cause of differential sound increase when moving out of comfort mode. Now Im beginning to wonder, although I personally experience no sound level increase unless its from rpm increase when switching modes.

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.

[GregoryK]

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.

[Aloha Joe]

Originally Posted by LinkF1

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.

Thanks Link, and very good points!

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! :

[boostm3]

Originally Posted by GregoryK

Check this...

https://www.leib-engineering.de/F87-...nit-BMW-F87-M2

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.

Greg, not sure what youre saying..Are you saying that because you can buy a product to install which regulates the valving, that Joe has that installed?

[GregoryK]

Originally Posted by boostm3

Greg, not sure what youre saying..Are you saying that because you can buy a product to install which regulates the valving, that Joe has that installed?

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.

[boostm3]

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. "

[Aloha Joe]

Originally Posted by boostm3

Joe, these changes in exhaust sound are clearly audible, correct? Im really stymied.. Could your DP have anything to do with it? You bought this car new, correct? Really mystified.

boost, I picked up this car new at BMW Welt for ED in May of 17 (euro plate pic in last post ). Put on 1,100 miles on ED, then another 100+ miles in Honolulu before bringing it in for the 1,200 miles service.

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.