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      10-05-2006, 09:31 AM   #20
JIMD1709's Avatar

Drives: 2007 328 Coupe Alpine White
Join Date: Aug 2005
Location: Saint Petersburg, Florida

iTrader: (8)

After doing this DIY, I have added an observation. Once you cut the filter out there is a very rough syrface, and it's COVERED in black charcaol dust.

I removed the MAF sensor from the airbox.( Just two #20 tork screws) BE CAREFUL with this part, it's fragile!! Then I used a dremel to smooth all the rough edges. Sandpaper will work too, but a dremel is faster.

Whether using sandaper or dremel it will create a TON of dust. I then washed the entire airbox, and let it dry completely. (this is why I removed the MAF sensor)

It's an easy mod, and the combination of adding a K&N filter, plus this mod, added a very noticeable improvement in throttle response, trust me. As for HP, probably not much, but it's still worth doing since down the road having that stupid charcoal filter in there will definitely cause airflow restriction since it's not replaceable!! It's almost like having two air filters, a poor design IMO. But, I guess a few states (CA for example) were concerned with vapors escaping into their precious atmosphere when the vehicle is turned off!? We have greater air concerns, believe me! OK, off my soap-box.

Last edited by JIMD1709; 10-05-2006 at 09:57 AM.