I have been reading the discussion in this thread (http://e90post.com/forums/showthread...=carbon+filter) for a while. Since no one post DIY yet, I decided to do it myself.

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I did the same thing! I completely removed the MAF (Better safe then sorry), then used a box cutter to remove the filter, then used a dremel to sand away, then I washed it out with a sprayer and soap, then put box on top of dehumidifier, and then re-installed.

There shouldn't be a reduction in MPG, or any real gain.

To the people that has done this.

So I changed my air filter awhile back so I don't exactly remember how it looks.

but when you guys cut out this charcoal filter..from the pics that looks like the air filter itself. Why not just take the filter out? unless I'm missing something in the picture

I remember when i replaced mine, which i believe was the piece that was cut, it comes off and i put in a new one ? Was there a second layer that I must've forgot ? or maybe my car didn't come with one..idunno, i ordered mine in spain through military sales so perhaps i got a european model unless they're suppose to get it too?

First Video in daytime is with charcoal removal.
Second Video at Night, is the mod i explained below

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OK so i took this the next step further by removing another peice, the intake is split into two pieces as you all know. The first has the MAF attached to it, and the other connects to the scoops in the kidney grilles. what i did was i removed the second peice, put my KNN filter on the first piece and then secured to the housing for a permanent fit. the sound it produces is amazing, and the awesome part is, if you have any issues, just reattach the other side and your good to go.

Opening up the box like that you are just sucking all the hot air from the engine bay. The power loss has gotta be pretty significant. Not to mention are you 100% sure the filter is attached securely? Any gaps would mean sucking all sorts of gunk into the engine.

Dude.... nice hot air intake mod.....
wow.....just wow.

I will be doing the charcoal filter removal though. Thanks for the write up on that part.

Is it bad that my first post on this forum is flaming someone? (I come from NASIOC, I can't help it)

...but it sounds so kewl!

I did this a while back ago and I'm glad I did. The car breathes so much better and the lag between 1st and 2nd gear is reduced significantly. I say it's worth it doing it. I have not had any problems at all.

Are you talking about the charcoal delete or the mod that i did

I'm pretty sure he's talking about the charcoal delete

sorry guys i should have metioned that its just the removal of the charcole filter.

So i drove the car around all day today, and no loss of power the car seems to be little faster, the engine does lose a little power at very high rpm but if you shift right before the loss the resulting shift to the next gear is a neck jerker, ill try to take a video of it today and show you guys, so far ive had pretty good results from the mod

Do know that the average temp is usually around 250 and with this mod it does go about two clips higher, during hard driving, so engine does get very hot,

more inputs please!

I'm using a Dremel to smooth out the surface where the charcoal element is molded into the intake air housing. Even after you cut/sand the plastic surfaces so they're smooth, you can still see particles charcoal in the plastic (this must be an insert molding process where they mold the plastic around the charcoal filter element). So, wanting to get 100% of the charcoal removed, I keep Dremeling the surface farther down. You really have to get deep before "all" the charcoal is gone - just need to be very careful not to cut into the regular air filter's seal surface. Based on previous comments, I'm guessing that many don't dremel/sand the surface down to the point where 100% of the charcoal is removed - which seems a bit risky...

I did the mod today and installed a K&N drop in air filter. Thanks for the initial post and photos!! I used a sharp blade to cut the carbon filter out and then I used wide blue painters tape to seal off the mass air meter. I followed with a rough file and then a dremel to smooth over the surface.

Easy mod and my initial 2 mile test loop brought with it a feel of improved throttle response and "grunt." Glad I did it and I will look forward to testing it out with a few more miles!

I just done it and replace the air filter with AFE Dry Pro.
So far, can't hear any differ at all.
But somehow, the RPM seem to go up slower for a little bit.
Is it only me??

sorry if this is a noob question, but does a 335 have a charcoal filter also ? if so has anyone removed it and did you see any gains ? thanks

Did it last night, took me 20 minutes. Totally worth the .25 HP gain. =)

Excellent DIY. I also cut the carbon filter out. How can BMW not make that replaceable?! Its a filter!!!! BTW, I cant believe my car had the original air filter in it. Stamp of BMW filter stated "5/25/05". Now I have to assume everything is original. Thanks again.

BTW, the thread of this DIY should be DIY: air filter and carbon filter. I came across this thread by accident looking to change out my air filter. I didn't even know about the carbon filter. I'm glad I stumbled upon this thread!