BMW M3 Forum (E90 E92)

BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   M3Post - BMW M3 Forum > E90/E92 M3 Technical Topics > Engine, Transmission, Exhaust, Drivetrain, ECU Software Modifications
 
GTB Performance
Post Reply
 
Thread Tools Search this Thread
      06-16-2009, 11:05 AM   #1
RL in Florida
Private First Class
5

 
Drives: 2008 Jet Black M3 Convertible
Join Date: Aug 2008
Location: SouthWest Florida


Posts: 123
iTrader: (2)

Charcoal stage in air filter...what does it do?

It looks like most of the High Performance Air Filters improve air flow by eliminating the Charcoal Stage of the filter, and using just the large particulate filter (paper/gauze/oil).

So, whats the charcoal there for? Remove hydrocarbons? Remove water?

I am looking at purchasing a high performance filter, but I'm just not wanted to take chances on causing engine damage if the charcoal actually is important.

Thanks for any input
Rick
Appreciate 0
      06-16-2009, 02:35 PM   #2
Thinker23
Private First Class
United_States
4

 
Thinker23's Avatar
 
Drives: '09 E92 M3 - AW, 6MT
Join Date: Apr 2009
Location: Bay Area


Posts: 186
iTrader: (1)

http://en.wikipedia.org/wiki/Activated_carbon

Activated charcoal is capable of trapping very small particles because of its microporosity. I believe non-charcoal based filters do not clean the air as well as charcoal based ones (can someone confirm this?)
Appreciate 0
      06-16-2009, 03:54 PM   #3
APEPerformance.com
United_States
4

 
APEPerformance.com's Avatar
 
Drives: E64 M6/E90 335xi
Join Date: Apr 2009
Location: Dallas


Posts: 322
iTrader: (1)

Send a message via AIM to APEPerformance.com
Quote:
Originally Posted by RL in Florida View Post
It looks like most of the High Performance Air Filters improve air flow by eliminating the Charcoal Stage of the filter, and using just the large particulate filter (paper/gauze/oil).

So, whats the charcoal there for? Remove hydrocarbons? Remove water?

I am looking at purchasing a high performance filter, but I'm just not wanted to take chances on causing engine damage if the charcoal actually is important.

Thanks for any input
Rick
I think it depends on which High performance filter you go with. I know the APE filter and the MS filter out ~99.39% of particles. Companies like AFE and others that use dry filters, don't filter as much. OE filters filter out about the same as ours, but are more restrictive on airflow.

Hope this helps
Appreciate 0
      06-16-2009, 04:04 PM   #4
FStop7
I like cars
Vatican City State
88

 
FStop7's Avatar
 
Drives: M6
Join Date: Oct 2008
Location: Newbury Park, CA


Posts: 5,059
iTrader: (3)

On the M5 the charcoal filters are meant to filter gasoline fumes that vent out of the intake path when the motor is shut off. Apparently the M3 has the same tendency. It's an emissions thing.
Appreciate 0
      06-16-2009, 04:14 PM   #5
montreal red
chris
Canada
146

 
montreal red's Avatar
 
Drives: White Boat
Join Date: Jun 2007
Location: Toronto


Posts: 12,127
iTrader: (31)

Send a message via MSN to montreal red
Quote:
Originally Posted by FStop7 View Post
On the M5 the charcoal filters are meant to filter gasoline fumes that vent out of the intake path when the motor is shut off. Apparently the M3 has the same tendency. It's an emissions thing.
+1
i believe this is true. i've heard of this issue as well.
__________________

Current: 2013 F10 M5 & 2013 GLK350
997.1 GT3RS (gone)
2009 WRX STI (gone)
e92 M3 (gone)
Appreciate 0
      06-16-2009, 04:47 PM   #6
GT3 Tim
Moderator
United_States
29

 
GT3 Tim's Avatar
 
Drives: 2008 E90 M3
Join Date: Feb 2008
Location: Sacramento, CA


Posts: 1,897
iTrader: (0)

Quote:
Originally Posted by FStop7 View Post
On the M5 the charcoal filters are meant to filter gasoline fumes that vent out of the intake path when the motor is shut off. Apparently the M3 has the same tendency. It's an emissions thing.
This is exactly what it is. It is called "evaporative emissions" and all cars must meet certain criteria. Typically, California has the most stringent regulations, and cars are manufactured to meet those standards. California most definately has an evap emissions standard for new cars. CARB tests cars to ensure they meet the standards. They wil test new cars (even ones that are not released yet), and also pay people a few hundred bucks to test thier "old" cars too...to ensure they are complying with the emissions warranty as required under seperate regulation. I think the emissions warranty on cars is 7 year/100K. They can test cars anywhere within this range to make sure the manufactures are meeting the design and regulatory limits.

Most likely, because of the intake tract design, and large amount of airspace in the plenumn, gas vapors can make their way out of the intake when the car is off. Thus, they installed charcoal filter media to absorb any rogue gasoline vapors. This way, along with a number of other things, BMW can comply with the regulations.
__________________
Tim (apparently likes "3" cars)
E90 M3 -- Current ride
2004 GT3 -- Sold
1997 M3/4 -- Sold
1995 M3 -- Sold
Appreciate 0
      06-16-2009, 05:54 PM   #7
tom @ eas
BimmerPost Supporting Vendor
United_States
315


 
tom @ eas's Avatar
 
Drives: BMW
Join Date: Nov 2005
Location: Anaheim, CA


Posts: 10,502
iTrader: (13)

Garage List
Quote:
Originally Posted by GT3 Tim View Post
This is exactly what it is. It is called "evaporative emissions" and all cars must meet certain criteria. Typically, California has the most stringent regulations, and cars are manufactured to meet those standards. California most definately has an evap emissions standard for new cars. CARB tests cars to ensure they meet the standards. They wil test new cars (even ones that are not released yet), and also pay people a few hundred bucks to test thier "old" cars too...to ensure they are complying with the emissions warranty as required under seperate regulation. I think the emissions warranty on cars is 7 year/100K. They can test cars anywhere within this range to make sure the manufactures are meeting the design and regulatory limits.

Most likely, because of the intake tract design, and large amount of airspace in the plenumn, gas vapors can make their way out of the intake when the car is off. Thus, they installed charcoal filter media to absorb any rogue gasoline vapors. This way, along with a number of other things, BMW can comply with the regulations.
Excellent post.
__________________
Appreciate 0
      06-16-2009, 06:10 PM   #8
swamp2
Lieutenant General
United_States
213

 
swamp2's Avatar
 
Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA


Posts: 10,201
iTrader: (1)

And by elimination the additional flow impedance of the charcoal stage you get a less restrictive intake system and hence some hp gain.
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 05:07 PM.




m3post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST