has anyone taken any or both foam peices out of their sound generator in their z4? does it make any difference???? Also has anyone fitted an aftermarket K&N cone filter onto their car, any noticable engine grunt or performance increase?? Has anyone tried the dinan ram air intake???

yeah, I took out both foam pieces. Its very easy to do, and makes a HUGE difference in sound. Because of it, I don't feel like spending money on intake and exhaust, considering its low horsepower/dollar ratio. Thats about $1k saved for a supercharger fund. Do it asap.

I heard a filter makes a slight difference, but ESS found the stock filter to be the most efficient one in THEIR testing.

will do! thanx

no, do it now

where is the sound generator and how do you remove the foam. i did a search and came up with nothing.

the sound generator is connected to the intake housing and it is a plastic pipe running into and through the firewall. i beleive the two foam peices are in the plastic piping peice closest and connecting to the firewall. pull it out and there will be two foam peices (one big, one small). please correct me if im wrong.

and what does that do for the car? just make it louder?

yep

last night i pulled everything apart... i saw no FOAM... in fact i put my arm in the whole and was able to reach all they way around, i could touch my fingers together through the grill and engine compartment...

Does anyone have pics of this part? If so, please put let us see it. It sounds confusing. Thanks

pictures, Anyone???

I would also be interested in pictures/detailed easy explaination.
Thanks in advance !

I would also be interested in pictures/detailed easy explaination.
Thanks in advance !

is it before or after the air filter?

Is this exclusive to the 2.5?

It is only on the 3.0+ for the 2.5 you can retrofit the sound generator but it is not standard equipment.

http://www.youtube.com/watch?v=GqmJGCsrRH0
3.0 with both pieces of foam out, mind the gay music


http://www.zpost.com/forums/showthread.php?t=63037
retrofit DIY install for the 2.5i


i purchased the parts from www.getbmwparts.com (http://www.getbmwparts.com), it was about $117 not including shipping and it takes 1-2 weeks to ship because they need to get some items from germany

Easy to do...
Sound generator foam
It sits behind air filter but in line
http://www.pezcyclingnews.com/photos/tech/bmc/sg1.jpg
loosen screw and wiggle off pipe.
http://www.pezcyclingnews.com/photos/tech/bmc/sg.jpg
foam sits inside
http://www.pezcyclingnews.com/photos/tech/bmc/sg2.jpg
pull it out and put the pipe back
http://www.pezcyclingnews.com/photos/tech/bmc/sg3.jpg


Popping just this piece is what I would suggest...

Not a big change in sound just putting around, but when you het 4500 RPM, the wail is great...


I also did the US only filter.

The second air filter (restrictive but designed simply to block unspent gas from leaking out when you turn engine off)
Sits over top of US car std air filters/// Just take a flat head screw driver and gently push into the crak and it will pop out easily
http://www.pezcyclingnews.com/photos/tech/bmc/filt2.jpg
Once it's out... Just reseal your airbox with the spring clips.
http://www.pezcyclingnews.com/photos/tech/bmc/filt3.jpg

I looked under the hood and found the sound generator. I guess it came standard since neither I nor the prior owner (my boss) did anything to the car. I also looked in the hose and there were no foam pieces. No wonder the car sounds awesome when I hit the gas pedal and when down shifting.

all 3.0 cars have it standard

Is it just me or is the part where the sound generator connects to the firewall very hard to put back on. Still I'm unsure if it's fully locked in because all I could do was give it a hard push there was no resounding "in"

does this void warranty?

The " Carbon Gas Exit" Filter can simply be snapped back into place. That said, I asked my dealer and the service manager said "Pop it out if you want. The Euro cars dont have em and they're designed to function when the car is turned off. They absolutely restrict air flow and if anything they make the care work harder..." Your dealer may have another view, but again, it can be popped in and out easily.


The sound generator does not void warranty. It is a small foam sound baffle and has no mechanical property.

Is this only in the 3.0 and M versions? I can't find anything like that on my 2.5.

I have never ever said "search" on a forum, but scroll up:lol

same thread.

Is this only in the 3.0 and M versions? I can't find anything like that on my 2.5.

to save you the trouble of scrolling up, 2.5i's don't come with sound generators

you have to purchase the parts straight from BMW, or if you're lucky enough, someone that is selling theirs

interesting news on the secondary air filter! As soon as my lil car gets back from the dealer, that sucker is coming out!

For anyone who has done this, does the car feel different afterwards?

I have taken both foam pieces out before, but since this car is my DD it got really annoying after about a week and I put them back in.

The air filter however, I am interested in.

I just checked my '03 3.0 for the 2nd air filter and it was not there. The air filter hoever had a layer od foam on the intake side about 1/8" thick. I have never seen this on an air filter - is it normal on a Z4 or is this a way around having an easily removable "gas" filter? The foam is glued in-place and cannot be removed.

I had about 1400 miles on our 3.0 when I removed the secondary air filter. We were traveling and immediately prior to that gas mileage was about 30.5 mpg. Afterward gas mileage increased, never going below 30.5 mpg. It is impossible to accurately measure the increase unless you compare the same road, same direction and same speed at the same time and temperature. Nevertheless, it seems that I am experiencing an increase in the vicinity of 0.5 mpg to 0.7 mpg.

I had about 1400 miles on our 3.0 when I removed the secondary air filter. We were traveling and immediately prior to that gas mileage was about 30.5 mpg. Afterward gas mileage increased, never going below 30.5 mpg. It is impossible to accurately measure the increase unless you compare the same road, same direction and same speed at the same time and temperature. Nevertheless, it seems that I am experiencing an increase in the vicinity of 0.5 mpg to 0.7 mpg.

i put a CAI on, I CAN DEFINATLY SEE INCREASED fuel economy... not sure about additional performance... but i am pulling a consistant 34 mpg freeway (top up) and 32 (top down)... city... its about the same as before 21 mpg.

the 2 filters in the sound generator... i removed both... but becuase the wife complained, I "comprimised" and put the small one back in.

One thing i do find annoying, is that little spring inside the sound generators that rattle at 2-3k rpm... i want to know if there is anyway to prevent the rattle.

to save you the trouble of scrolling up, 2.5i's don't come with sound generators

you have to purchase the parts straight from BMW, or if you're lucky enough, someone that is selling theirs

Posting before reading > me

But why would I even want a sound generator? It looks like everyone is ripping them out.

They're not ripping them out, we're removing the foam sound baffle inside to let more sound pass through.

mike87,

Did you follow the part numbers exactly from that zpost.com forum thread? Correct me if I'm wrong (just want to make sure), but there wouldn't be any difference in US and European parts, right?


http //www youtube com/watch?v=GqmJGCsrRH0
3.0 with both pieces of foam out, mind the gay music


http //www zpost com/forums/showthread php?t=63037
retrofit DIY install for the 2.5i


i purchased the parts from
www getbmwparts com, it was about $117 not including shipping and it takes 1-2 weeks to ship because they need to get some items from germany

Any increase in sound from removing the secondary carbon filter?Seat of the pants difference?Thanks

all 3.0 cars have it standard

My 06 3.0i did not come with one. Below pic is what a 3.0i looks like without one, it's a bird beak kinda thing.

Any increase in sound from removing the secondary carbon filter?Seat of the pants difference?Thanks

I have a K&N and have removed the carbon filter, no a big difference, but you can notice.

http://i204.photobucket.com/albums/bb270/anpmech/8232007033-1.jpg

Well took it out, noticed it was a bit louder. I have both the foam and the carbon taken out. Its not FI hp difference, but It feels a bit more on the upper end. I also noticed the US cars are 255hp vs the er at 265, why?

I pulled out the foam piece at the firewall today after reading this thread. The difference is amazing! I only hear the increased sound at WOT or above 3500 rpm and heavy throttle, but not necessarily WOT.

Interestingly, in my '05 3.0i, I did not have a foam piece at the junction of the sound generator and the airbox elbow, nor did I have a carbon filter above the air filter, which I had previously swapped for a K&N. That switch yielded no noticeable change, but oh boy did today's mod!

If I understand things correctly, the sound generator has no performance value and simply increases the noise level within the car. Removing the foam simply increases the noise level.

I certainly appreciate the auditory feedback from any high performance vehicle, and my Z4 is no exception. The enjoyment comes from the relationship between the increased noise corresponding to increased performance. I am not one who would spend serious money on an exhaust or intake system simply to make the car sound better (louder) with no performance gain.

Is there any problems with blocking off the sound generator? It looks like it would be easy enough to remove the connector tube between the intake and firewall and cap off the openings. What are your thoughts? Thanks.

If I understand things correctly, the sound generator has no performance value and simply increases the noise level within the car. Removing the foam simply increases the noise level.

I certainly appreciate the auditory feedback from any high performance vehicle, and my Z4 is no exception. The enjoyment comes from the relationship between the increased noise corresponding to increased performance. I am not one who would spend serious money on an exhaust or intake system simply to make the car sound better (louder) with no performance gain.

Is there any problems with blocking off the sound generator? It looks like it would be easy enough to remove the connector tube between the intake and firewall and cap off the openings. What are your thoughts? Thanks.

You would have to get the setup thats on my car. There is a block off plate in the firewall and the plastic assembly in the pic I posted above and you are done. Also makes for a less cluttered engine bay.

Yeppers,

It's just a tuneable noise thing.

I spoke to an engineer at BMW while at a bike race in Germany and he said "there are a couple of foam pieces that you can tune the sound with. remove none or 1 or more depending on prefrences. It's just something to please the driver as different types of people will buy this car."

Pretty cool actually.

You would have to get the setup thats on my car. There is a block off plate in the firewall and the plastic assembly in the pic I posted above and you are done. Also makes for a less cluttered engine bay.

Anpmech, thanks! Sounds like a project for the next rainy weekend along with pulling out the carbon air filter.

my 06' M doesn't have one... poo. i guess i'll be doing the exhaust, in order to coax a little bit more of that growl out of her ;)

has anyone taken any or both foam peices out of their sound generator in their z4? does it make any difference???? Also has anyone fitted an aftermarket K&N cone filter onto their car, any noticable engine grunt or performance increase?? Has anyone tried the dinan ram air intake???

I took the foam pieces out last night...

WOW @ 5000 rpms WOT it is very loud and there is a lot of air vibration ( windows closed and top up)

I put the big piece back in but I think I will try tuning by cutting the big piece little by little to get the sound were it is noticable but not too loud.

:buttrock

does anyone in the Atlanta area know how to do this?

ok i went out and all I saw was that plastic double cup. there was no foam anywhere. I took apart the air intake and nada.

does anyone in the Atlanta area know how to do this?

Nfilsoof1, the following link to my post may help. It is a simple diy project.

http://forums.bimmerforums.com/forum/showthread.php?t=926025

I've got the carbon filter but no foam, it's pretty much identical to Anpmech's picture. It's got an enclosed expansion chamber right before the throttle body. I've removed the Carbon filter but don't want to test drive it in this rain/sleet. Both the Carbon filter and the intake box stink of gas. The carbon filter was marked "DO NOT REMOVE!" :)

I've got the carbon filter but no foam, it's pretty much identical to Anpmech's picture. It's got an enclosed expansion chamber right before the throttle body. I've removed the Carbon filter but don't want to test drive it in this rain/sleet. Both the Carbon filter and the intake box stink of gas. The carbon filter was marked "DO NOT REMOVE!" :)

Don't worry, That's EPA stuff, not anything that will hurt your car. That filter just sucks up gas fumes after you shut down, and does nothing but make your engine breath a liitle worse. I would also call that an expansion chamber as you did, and it is there for a reason. Maybe BMW is testing a new version of the sound generator on some models, why else would that be there? It is definatly better looking than the pipes routed into the firewall. Who knows? I have no problems with my car and the way it sounds inside or out.

I'm not quite sure its an expansion chamber. I checked out the sound generator on my 3.0, and there is a membrane just to the side of the intake elbow that prevents any air from the sound generator being pulled directly into the engine. I'm sure this membrane also helps to acoustically tune the noise heard in the cabin, but its primary function has to be preventing unfiltered air from entering the engine. Even with the duck bill attachment anpmech posted, there is likely still a membrane there, otherwise they would be throwing off the aerodynamics of the intake tract and causing a small area of vacuum right next to the intake throttle body... wouldn't want that.

Thanks, thats good to know it won't hurt my engine. I agree it's a better looking solution and easy to remove if you need access on that side of the engine. I'm very happy with the sound of the car, I was just hoping to remove any unnecessary airflow restrictions. With the carbon filter removed I really didn't notice a sound difference but my ears aren't great.

The duck bill or expansion chamber had 2 air inlet/outlets about an inch and a half each.

I looked under the hood of my M Coupe last night and there's no sound generator, so this must be exclusive to the Z's. I did, however, see the 2nd air filter so I went ahead and removed it. On the drive to work this morning I listened very carefully and heard no difference in the sound, but I imagine it would restrict air flow (like many other's are saying) so I guess I'll just leave it out.

ampech, I have a 2007 3.0si, and my air filter looks just like yours - the "bird beak" kind of plastic part in your posted photo. There is no tube connecting the air filter to the firewall. Does this mean that I have no sound generator, or are people saying that the bird beak is the sound generator? Anyone have any ideas?

Thanks for your help.

Best,
Jinnahnh

ampech, I have a 2007 3.0si, and my air filter looks just like yours - the "bird beak" kind of plastic part in your posted photo. There is no tube connecting the air filter to the firewall. Does this mean that I have no sound generator, or are people saying that the bird beak is the sound generator? Anyone have any ideas?

Thanks for your help.

Best,
Jinnahnh

You don't have one. I can't figure this so I gave up. The only thing I can say is some have it some don't, roll the dice and open the hood and look, and none of the M's have one.

You don't have one. I can't figure this so I gave up. The only thing I can say is some have it some don't, roll the dice and open the hood and look, and none of the M's have one.


Does anyone else know why some 3.0i's do not have the sound generator, whereas others do? If all 3.0's are meant to come with them, would the dealer install one for you if you didn't get one?

Thanks by the way, I really appreciate the wealth of knowledge that you can find by reading this forum.

Best,
Jinnahnh

I have seen on some VWs that cars destined for states with harsher emissions testing may have a slightly different set-up. My guess is that BMW has done the same thing.

BTW that video is pretty much spot on for top end scream. However my wife is considering letting me straight pipe it after my service appt next week. So that will definitely out volume the removal of the foam.

The 2006 Z4's are ALL 3.0.......2 models, 3.0i and 3.0is. I have the 3.0i which replaced the 2005 and older 2.5i models......Just like the 2.5i, the 3.0i's DO NOT have the sound generator....I know this because I have a 2006 3.0i. Hope this helps.

I just want to make mine faster and more torquey.....anyone know whats out there that works????????????

Does anyone else know why some 3.0i's do not have the sound generator, whereas others do? If all 3.0's are meant to come with them, would the dealer install one for you if you didn't get one?

Thanks by the way, I really appreciate the wealth of knowledge that you can find by reading this forum.

Best,
Jinnahnh

...idk what you're talking about. my 3.0i had one and i took both foam pieces out. put the smaller one back though. too loud imo. but yea, the 3.0's definitely have the noise generator.

I just want to make mine faster and more torquey.....anyone know whats out there that works????????????


turbo.

I have a 2007 3.0i and has absolutely nothing in there. Just that double cup thing at the end of the air intake hose exactly like anpmech pictures

post a picture of ur engine bay.

I've tried removing just the big foam and now the little foam. Wasn't a big fan of removing the big foam. Louder, but a little too harsh sounding at the top end. Put the big foam back in and took out the little foam. Similar volume, but a more interesting sound. More honk, kind of like a porsche sound around 4 grand rpm's. Now I'm thinking about cutting both pieces of foam in half. Anybody experiment with different sizes of foam like this?

I took both out and love the sound so far. It only really gets loader around 4k :alrightand thats when I want to here it working. It even feels faster.