Drivetrain R56 Noisemaker Revealed!
#1
12-30-2009, 01:30 PM
R56 Noisemaker Revealed!
I installed the NM Engr. cold side boost tube on SUnday and pulled all the "Noisemaker" tubing out. Have seen a bunch of speculation on NAM about just what the "Noisemaker" is, so I decided to find out. Picture 1 is the noisemaker by itself - the left side connects to the cold-side boost tube and the right side has a tube that runs through the plastic firewall and dumps into the cowl space.
I took a band saw and cut the end of the noisemake off. Picture 2 is what you get.
The right cap has a very stiff plastic bellows connected to it. The left side is just a cup. The right cap fits into some grooves and looks to have been attached with epoxy. Just to see how stiff the bellows is I put 60 lbs of weight (equiv. to about 10 psi boost) on it and it didn't move. That makes me think it is acting as just a vibrating membrane (read ear drum) that amplifies the sound of the blowoff which is occuring just upstream. The is no bleed or blowoff through this "noisemaker, so for sure it doesn't hurt anything to get rid of it. Can't say that I missed any noise as my DDM intake and Alta Catback provide plenty of aural stimulation.
Cheers,
Greg
I took a band saw and cut the end of the noisemake off. Picture 2 is what you get.
The right cap has a very stiff plastic bellows connected to it. The left side is just a cup. The right cap fits into some grooves and looks to have been attached with epoxy. Just to see how stiff the bellows is I put 60 lbs of weight (equiv. to about 10 psi boost) on it and it didn't move. That makes me think it is acting as just a vibrating membrane (read ear drum) that amplifies the sound of the blowoff which is occuring just upstream. The is no bleed or blowoff through this "noisemaker, so for sure it doesn't hurt anything to get rid of it. Can't say that I missed any noise as my DDM intake and Alta Catback provide plenty of aural stimulation.
Cheers,
Greg
#3
12-30-2009, 05:47 PM
it's more of a fine tuning device... not in terms of performance but sound.
Early in the development process, BMW began to research what customers prefer as a sporty sound from the car’s engine. Once again a roadster presents unique challenges to the engineers because the acoustics are much different whether the top is up or down.
The process began in the sound lab with people listening to different sound samples. These samples were engine noises but they had been synthetically created on the computer. The goal was to find the ideal roadster sound. This sound shouldn’t be so loud as to disturb one’s neighbors but it should be louder than a luxury sedan. The sound must be “solid” and correspond to what is expected from a BMW. These aspects were all combined and a sound target was designed. This sound target, which is stored as a computer file, was specified in terms of tone and decibel levels. But it also was somewhat subjective.
On the real car, the sources that contribute to the sound the driver and passenger hear include the engine itself, the air intake and the exhaust. The engine noise is very mechanical sounding and while, for example, a Ferrari’s sound is indeed very mechanical; BMW feels that their cars should be more refined.
For the 3.0-liter model only, a special “sound generator” was developed. “Sound generator” is a misnomer; “selective sound
filter” would be more accurate. In any case, the sound of the engine is managed in a very specific manner. The sound generator brings the sound back to the firewall to make it more apparent to the driver and passenger. In addition, this system filters out some of the naturally occurring sounds and selects others. The sounds that are selected for are those associated with a performance roadster. The result is a sound, especially upon acceleration, similar to a big V8 engine. Not only is the sound pleasing but it also provides feedback to the driver; the power is heard as well as felt.
In the BMW acoustic labs, the various components can be tested independently. On all three models, 2.2, 2.5 and 3.0 liter, the various sounds are graphed over the whole engine range. The characteristics can be mixed and tuned to complement one another. The process is almost like a musician mixing a recording. Testing is then done in an acoustic chamber with a rolling road. Final testing is, of course, done on actual roads.
The process began in the sound lab with people listening to different sound samples. These samples were engine noises but they had been synthetically created on the computer. The goal was to find the ideal roadster sound. This sound shouldn’t be so loud as to disturb one’s neighbors but it should be louder than a luxury sedan. The sound must be “solid” and correspond to what is expected from a BMW. These aspects were all combined and a sound target was designed. This sound target, which is stored as a computer file, was specified in terms of tone and decibel levels. But it also was somewhat subjective.
On the real car, the sources that contribute to the sound the driver and passenger hear include the engine itself, the air intake and the exhaust. The engine noise is very mechanical sounding and while, for example, a Ferrari’s sound is indeed very mechanical; BMW feels that their cars should be more refined.
For the 3.0-liter model only, a special “sound generator” was developed. “Sound generator” is a misnomer; “selective sound
filter” would be more accurate. In any case, the sound of the engine is managed in a very specific manner. The sound generator brings the sound back to the firewall to make it more apparent to the driver and passenger. In addition, this system filters out some of the naturally occurring sounds and selects others. The sounds that are selected for are those associated with a performance roadster. The result is a sound, especially upon acceleration, similar to a big V8 engine. Not only is the sound pleasing but it also provides feedback to the driver; the power is heard as well as felt.
In the BMW acoustic labs, the various components can be tested independently. On all three models, 2.2, 2.5 and 3.0 liter, the various sounds are graphed over the whole engine range. The characteristics can be mixed and tuned to complement one another. The process is almost like a musician mixing a recording. Testing is then done in an acoustic chamber with a rolling road. Final testing is, of course, done on actual roads.
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'08R56 (04-14-2020)
#5
01-02-2010, 05:25 AM
#6
01-02-2010, 05:51 AM
No Moving Parts
I was surprised to find there were no "moving" parts in this thing. I believe it simply acts like a speaker. The end of the bellows deflects slightly when the pressure changes on the turbo side. The bellows acts as a chamber that turns this change in pressure to sound (a la a speaker cone) and it goes out the tube to the cowl area. I really don't see this thing doing anything as sophisticated as described in mellowmcs's quote.
Cheers & Happy New Year,
Greg
#7
01-02-2010, 05:59 AM
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#10
01-05-2010, 02:02 PM
What the hell is wrong with cars nowadays?
How many of you would have preferred a M______ F______ water temperature gauge over this worthless pile of dog dookie?
It seems like every car made nowadays has 200 lbs of worthless crap that needs to be tossed in the trash. You can't even buy a pickup truck nowadays without automatic ball sack warmers and seven cup holders.
....ok had to vent a little
It seems like every car made nowadays has 200 lbs of worthless crap that needs to be tossed in the trash. You can't even buy a pickup truck nowadays without automatic ball sack warmers and seven cup holders.
....ok had to vent a little
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RChandler (11-11-2020)
#11
03-03-2010, 12:30 PM
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$1.00 Noisemaker Delete!
This is what I used to plug the hole in the noisemaker opening, 1" PVC cap, it slides in very snug if you put the open end pointed out.
$1 at Home Depot and a decent helping of GOOP Automotive Sealant. Been on for 6 months and I checked it yesterday, its solid as a rock and not going anywhere.
http://www.amazon.com/Charlotte-Pvc-.../dp/B000R9DZ42
This is what I used to plug the hole in the noisemaker opening, 1" PVC cap, it slides in very snug if you put the open end pointed out.
$1 at Home Depot and a decent helping of GOOP Automotive Sealant. Been on for 6 months and I checked it yesterday, its solid as a rock and not going anywhere.
http://www.amazon.com/Charlotte-Pvc-.../dp/B000R9DZ42
Last edited by TheMadDane; 03-03-2010 at 12:37 PM.
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03-15-2010, 07:41 AM
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#16
06-25-2010, 12:20 PM
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06-26-2010, 06:44 AM
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#19
07-31-2010, 11:57 AM
Noisemaker Location
clnconcepts:
On the R56S the noisemake is behind and under the stock airbox mounted on the plastic bulkhead. There is a tube going from the left side to the cold-side boost tube just before the boost tube connects to the throttle body. It is part #13 in the diagram below (thanks RealOEM).
The part on the right side (#16) just plugs into a hole in the bulkhead.
Cheers,
Greg
On the R56S the noisemake is behind and under the stock airbox mounted on the plastic bulkhead. There is a tube going from the left side to the cold-side boost tube just before the boost tube connects to the throttle body. It is part #13 in the diagram below (thanks RealOEM).
The part on the right side (#16) just plugs into a hole in the bulkhead.
Cheers,
Greg
#20
07-31-2010, 12:34 PM
#21
07-31-2010, 01:40 PM
tvrgeek,
I bought a TIS DVD on E-Bay for like $5. It has BMW's whole line through Spring of 2008. But it is not as good as the DIY threads on NAM in most cases. The TIS also doesn't have wiring diagrams.
Where in Maryland are you? If you have a one time need I could maybe meet you somewhere and let you borrow the DVD.
Cheers,
Greg
PS - The diagram I posted is from Real OEM. If you are just looking to see how things are put together you can get a lot of info from that (and part numbers/prices).
I bought a TIS DVD on E-Bay for like $5. It has BMW's whole line through Spring of 2008. But it is not as good as the DIY threads on NAM in most cases. The TIS also doesn't have wiring diagrams.
Where in Maryland are you? If you have a one time need I could maybe meet you somewhere and let you borrow the DVD.
Cheers,
Greg
PS - The diagram I posted is from Real OEM. If you are just looking to see how things are put together you can get a lot of info from that (and part numbers/prices).
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08-06-2010, 06:20 AM
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08-06-2010, 09:08 PM
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#24
08-07-2010, 12:47 AM
#25
08-07-2010, 06:47 AM
As Czar says, it is a muffler in the hot-side charge pipe. The wastegate for the turbo is just upsteam so I expect this is to baffle some of that noise.
Alta, NM, Forge and several others make replacement hot-side charge pipes that delete this muffler.
It is interesting to note that MINI calls the stock air box and air filter the "intake muffler". I expect for the same reason - to hide some of the blow off noise.
Cheers,
Greg
Alta, NM, Forge and several others make replacement hot-side charge pipes that delete this muffler.
It is interesting to note that MINI calls the stock air box and air filter the "intake muffler". I expect for the same reason - to hide some of the blow off noise.
Cheers,
Greg