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Z4 M Coupe
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Discussion Starter #1
I was cleaning the engine compartment this afternoon, and I decided to take a look at the air filter box. Well, I unclipped it and opened it. To my surprise there were not one, but two air filters. Theres an orange one in the lower section, and a gray one hidden in the upper section. Can anyone say whether one of the filters can be removed?
 

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19,585 Miles
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11,141 Posts
england1987 said:
I was cleaning the engine compartment this afternoon, and I decided to take a look at the air filter box. Well, I unclipped it and opened it. To my surprise there were not one, but two air filters. Theres an orange one in the lower section, and a gray one hidden in the upper section. Can anyone say whether one of the filters can be removed?
I have two of the orange ones in stock since I change my air filters every 3,000 miles.
I've opened it up now. Interesting. Gray one is not in the parts system.

http://bimmerfest.com/forums/showthread.php?t=137426&highlight=air+filter

Also as a tip, the MAF sensor is more if purchased separately than the whole air assembly which comes with the MAF, filter and everything else.
 

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19,585 Miles
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11,141 Posts
england1987 said:
Theres an orange one in the lower section, and a gray one hidden in the upper section.
The upper section is not available as a separate item.
Tried buying it so I could engrave M Power on the top.
Will try the engraving this Winter.
Will also be buying the assembly since I want to have a MAF in stock.
 

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19,585 Miles
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11,141 Posts
Probably a noise thing. Pre filter dosen't let the gray one get dirty.
I like the noise the way it is.
Someone has to remove it to see.
Varoom.

The car is amazing. The engine is amazing. You already know that.
 

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matching revs in
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400 Posts
I believe the gray one to be a charcoal filter (not for the cabin) like the one that's in the E60 M5.
Well-documented here:
Charcoal filter removal
 

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19,585 Miles
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11,141 Posts
Fast6 said:
I believe the gray one to be a charcoal filter (not for the cabin) like the one that's in the E60 M5.
Well-documented here:
Charcoal filter removal
Here's a pic of the Z4 M one.
Euro air box is a different number. Orange filter and MAF are the same.
Unprogrammed DME is the same. Programed ones are different.
We also have the crap on top of the engine but Euro doesn't.

 

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Back in the fold
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That is a charcoal Filter like my M5 "had"

Hi, I'm new here, and this is my 1st post, but have had an E60 M5 for many months, and I can verify that the pic shown here is indeed a charcoal pre-filter. Now, whether it simply comes out like the 2 on my M5's did, is another question, since the cleaner assemblies are different. My guess is that it can be removed without any problems. I didn't get a CEL when mine were removed. Would like to know, since it did make a positive difference in the way the engine breathed, and to a smaller extent, sounded.
 

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Z4 M Coupe
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157 Posts
Discussion Starter #8
Goodwood said:
Hi, I'm new here, and this is my 1st post, but have had an E60 M5 for many months, and I can verify that the pic shown here is indeed a charcoal pre-filter. Now, whether it simply comes out like the 2 on my M5's did, is another question, since the cleaner assemblies are different. My guess is that it can be removed without any problems. I didn't get a CEL when mine were removed. Would like to know, since it did make a positive difference in the way the engine breathed, and to a smaller extent, sounded.
Refer to "easy mod for US M models". To answer quickly, yes it comes out, no, theres no sound difference. And horsepower is increased 5hp through mid range and 1hp @ peak RPM
 

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19,585 Miles
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11,141 Posts
Internet truth (charcoal filter)

Someone showed me a technical service bulletin (group 12) related to this,
dated August 2007.
Ask your dealer to show it to you.
You may want to put it back in.
 

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The knights who say Ni!
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456 Posts
+1 :dunno: Mine's been out for a year now...
 

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TMS
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9,288 Posts
Someone showed me a technical service bulletin (group 12) related to this,
dated August 2007.
Ask your dealer to show it to you.
You may want to put it back in.
Buried in Palantirion's long mod thread is an observation he made that removing the filter had no perceivable effect when measured on the dyno.
 

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Calvinball Professional
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1,104 Posts
Someone showed me a technical service bulletin (group 12) related to this,
dated August 2007.
Ask your dealer to show it to you.
You may want to put it back in.
Please do elaborate. If you can't post for confidentiality reasons, a PM would be greatly appreciated.
 

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My kine-a town.
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420 Posts
Someone showed me a technical service bulletin (group 12) related to this,
dated August 2007.
Ask your dealer to show it to you.
You may want to put it back in.
Can you shed some light on the nature of the bulliten? Why should we put it back in? Has the the bulletin been posted anywhere?

...and this mod does not produce any additional horsepower or sound. I removed mine because I was under the impression that the Euro models do not have them and I hate that we get all this extra crap mandated for us in the States. ...all the restrictions none of the fun stuff...
 

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Registered User
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866 Posts
Can you shed some light on the nature of the bulliten? Why should we put it back in? Has the the bulletin been posted anywhere?

...and this mod does not produce any additional horsepower or sound. I removed mine because I was under the impression that the Euro models do not have them and I hate that we get all this extra crap mandated for us in the States. ...all the restrictions none of the fun stuff...
I have seen and read the bulletin. I put my charcoal filter back in because I was experiencing one of the symptons listed on the bulletin. I guess the DME software is looking for whatever changes this filter provides. :dunno:

The bulletin number I saw is 12 12 07.
 

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Calvinball Professional
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1,104 Posts
I have seen and read the bulletin. I put my charcoal filter back in because I was experiencing one of the symptons listed on the bulletin. I guess the DME software is looking for whatever changes this filter provides. :dunno:

The bulletin number I saw is 12 12 07.
What symptom specifically was it exhibiting?
 

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I removed my secondary filter at about 2000 mi and noticed no drivabilty problems whatsoever. Everything seemed to be the same powerwise, but gas mileage did increase perhaps partially due to motor breaking in.
My understanding is that the U.S. alone does a 24 hour "soak test" (sic) in a closed room to determine if there are any emisision leaking from a motor. Without a butterfly throttle, the Z4 will emit tiny amounts of raw gas fumes, and this filter will absorb them.
 

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Registered User
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866 Posts
What symptom specifically was it exhibiting?
It was hesitating/surging at some RPM levels. This would start for no reason and the only way to stop it was to either speed up or slow down. I haven't driven it enough since the re-install to determine if this indeed eliminates it. It'll take a few weeks to be sure.
 

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Calvinball Professional
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1,104 Posts
It was hesitating/surging at some RPM levels. This would start for no reason and the only way to stop it was to either speed up or slow down. I haven't driven it enough since the re-install to determine if this indeed eliminates it. It'll take a few weeks to be sure.
I was told that was a peculiarity of the drive by wire throttle, and I have experienced it both with and without the carbon filter. For me it is a bucking or lurching upon easy acceleration from about 3,000 rpm. I have to take my foot off the gas for a second and it then composes itself. It can be a little embarassing as to outside observers it looks like you can't drive a manual when it happens.:eek:
 
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