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07-30-2012LAST POST
05-09-2006
05-09-2006
younghov85
Captain
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I just finished removing my charcoal filter and went out for a test drive. The car seems to have a cleaner acceleration and a better tone under heavy acceleration. It seemed just a tad bit quicker but having a nicer tone was about the biggest change noticed.
05-11-2006
05-11-2006
visor
BMW, can I have some LSD please?
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javajaws wroteYou're correct on the adsorption part, but it is not a permanent bond.But if you are doubting that a carbon filter can become exhausted then I suggest you read up on how carbon filters work....in short they clean air by trapping chemicals in the pores of the carbon...which lose their efficiency over time as the pores of the carbon fill in and eventually become "full". Once the carbon has been used up it is doing nothing but getting in the way. BTW, the chemical process for this is adsorption (not absorption).
The carbon will be regenerated (ie. the trapped gas molecules that permeated out from the engine will be released) everytime when the car is started up and air flows into the airbox past the regular and charcoal filters into the engine.
05-11-2006
05-11-2006
bt304
Enlisted Member
2
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I removed the filter last night and took a test drive. It does seem to rev easier or quicker. I don't think It's much louder, just sounds better. Hard to explain but sounds a bit more "mechanical" sounding or not as muted as before. A little more like past BMWs (to me). I was reluctant at first, took me about 20 minutes of staring at the thing until I finally decided to start cutting.
05-16-2006
05-16-2006
KC Bimmer
Second Lieutenant
31
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256
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I'm doing mine on Thursday (have the afternoon off). I'm really interested to see if I notice a difference.
05-17-2006
05-17-2006
javajaws
Private
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visor wroteYou can't reactivate a carbon filter by simply blowing some air into it. The bond between the carbon and the pollutants is stronger than that. Reactivating carbon ususally requires a specialized heat treating process which is obviously not applicable here due to the non-removable aspect of the filter.You're correct on the adsorption part, but it is not a permanent bond.
The carbon will be regenerated (ie. the trapped gas molecules that permeated out from the engine will be released) everytime when the car is started up and air flows into the airbox past the regular and charcoal filters into the engine.
09-20-2006
09-20-2006
Richwm
Captain
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It’s been two weeks since I did this mod and here is my opinion, I have better acceleration and better gas mileage. One thing of note I just went over 32k miles and I think that filter was wearing out. Last year I was getting from 29.2 to 30.7 mpg at 75 Mph and right before I cut the filter out I was down to 27.2 to 27.8 at 75 Mph and the car was starting to feel sluggish. Now all my power is back and maybe a little more and my gas mileage is 29.7 to 31.2 at 75 Mph.
These tests were done with the cruse control on 75 for most of the trip and during my 72-mile trip to work almost all freeway 1/2 hills and the other half is flat ground.

These tests were done with the cruse control on 75 for most of the trip and during my 72-mile trip to work almost all freeway 1/2 hills and the other half is flat ground.
08-05-2007
08-05-2007
JWadle
Since '75: 530i/733i/745Turbo/M5/M6/325iX/540i
9
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I assume this would have littlle benefit on a 335? From what I've read, increased airflow for a turbo does not have the benefits it does for an NA engine.
I am far from an expert on this topic, so if I'm wrong please say so.
I am far from an expert on this topic, so if I'm wrong please say so.
01-30-2008
01-30-2008
i8_it
Feeling Blue.
131
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801
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so technically we are just removing that charcoal filter?
01-30-2008
01-30-2008
///AFRO
Stage 1 Juice Box - Boosted'
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1.5K
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So, can this charcol thing work for the e90/e92 335i?
01-30-2008
01-30-2008
imaznumkay
Major
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1.1K
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i dont think there are charcoal filters in 335i stock boxes imo
01-30-2008
01-30-2008
BoLaS
Captain
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664
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charcoal filter on 335 = big fat negative ghost rider...
01-30-2008
01-30-2008
NPDAN
Colonel
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2.6K
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BoLaS wroteI didnt read thru the entire thread. Does this mean that there are NO charcoal filters in the E92 335's?charcoal filter on 335 = big fat negative ghost rider...
01-31-2008
01-31-2008
i8_it
Feeling Blue.
131
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801
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I did it to my car today...and I am pleased with it. Smoother acceleration and i actually do believe the throttle response has improved. It also has a nicer sound to the engine now, a bit more noticeable then before. I recommend it.
11-03-2011
11-03-2011
BoogeyMan'sBMW
Lieutenant Colonel
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1.9K
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so do we just cut out the filter and thats that or do we have to replace that filter with something else (ie a K&N filter)?
11-04-2011
11-04-2011
joegeeZe
Private First Class
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170
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BoogeyMan'sBMW wroteso do we just cut out the filter and thats that or do we have to replace that filter with something else (ie a K
11-04-2011
11-04-2011
joegeeZe
Private First Class
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170
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BoogeyMan'sBMW wroteso do we just cut out the filter and thats that or do we have to replace that filter with something else (ie a K
11-04-2011
11-04-2011
jaceaholic
thestream.tv
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BoogeyMan'sBMW wroteyou just cut out the charcoal filter that sits right behind the paper filter.. you can use the paper filter over again or you can buy a K&N filter.. its up to you~!so do we just cut out the filter and thats that or do we have to replace that filter with something else (ie a K&N filter)?
11-04-2011
11-04-2011
BoogeyMan'sBMW
Lieutenant Colonel
137
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jaceaholic wrotehttp://www.e90post.com/forums/attachment.php?attachmentid=27617&stc=1&d=1149463043you just cut out the charcoal filter that sits right behind the paper filter.. you can use the paper filter over again or you can buy a K&N filter.. its up to you~!
http://www.e90post.com/forums/attachment.php?attachmentid=27618&stc=1&d=1149463043
so that is the filter correct^ is that the paper filter or the charcoal filter or both? lol sorry for my noobish questions
11-04-2011
11-04-2011
branmace
Private First Class
6
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108
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BoogeyMan'sBMW wroteThat is the charcoal filter. You might want to sand down the edges of the box, where you cut out the charcoal filter (if they are rough). If you do that, i would recommend to pull out the Mass Air Flow (MAF) sensor, the thing that is inside the air box pipe opening on your picture behind the charcoal filter you cut out, so you don't dust it. Wipe/wash out the air box afterwords, air/blow dry it, clean the MAF with CRC MAF cleaner (from you local AutoZone, Checkers, O'Rileys etc), a K&N filter is always nice p/n 33-2332, assemble back together and enjoy the difference.http://www.e90post.com/forums/attachment.php?attachmentid=27617&stc=1&d=1149463043
http://www.e90post.com/forums/attachment.php?attachmentid=27618&stc=1&d=1149463043
so that is the filter correct^ is that the paper filter or the charcoal filter or both? lol sorry for my noobish questions
11-04-2011
11-04-2011
BoogeyMan'sBMW
Lieutenant Colonel
137
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1.9K
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branmace wroteso i will be replacing this filter:That is the charcoal filter. You might want to sand down the edges of the box, where you cut out the charcoal filter (if they are rough). If you do that, i would recommend to pull out the Mass Air Flow (MAF) sensor, the thing that is inside the air box pipe opening on your picture behind the charcoal filter you cut out, so you don't dust it. Wipe/wash out the air box afterwords, air/blow dry it, clean the MAF with CRC MAF cleaner (from you local AutoZone, Checkers, O'Rileys etc), a K&N filter is always nice p/n 33-2332, assemble back together and enjoy the difference.
http://www.e90post.com/forums/attach...1&d=1149463043
with the K&N filter correct?
11-04-2011
11-04-2011
branmace
Private First Class
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BoogeyMan'sBMW wroteNo. That filter is the charcoal filter. You throw that away. The other filter in your box. I hope you had another filter in your box. It is paper filter, white with orange/yellow rubber all abound the edge. This paper filter you replace it with the K&N filter. If you search online the K&N filter part number i posted above (K&N 33-2332), you will see what it looks like the filter you are replacing it.so i will be replacing this filter:
http://www.e90post.com/forums/attach...1&d=1149463043
with the K&N filter correct?
11-05-2011
11-05-2011
BoogeyMan'sBMW
Lieutenant Colonel
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branmace wrotethanks that makes a lot more sense!No. That filter is the charcoal filter. You throw that away. The other filter in your box. I hope you had another filter in your box. It is paper filter, white with orange/yellow rubber all abound the edge. This paper filter you replace it with the K&N filter. If you search online the K&N filter part number i posted above (K&N 33-2332), you will see what it looks like the filter you are replacing it.