Originally Posted by 620BMW325i
Old thread to revive but...
Why do people claim putting a k&n drop in filter is worse than the OEM filter? Should I just buy an OEM air filter and replace mine? How come you have to change your oil and oil filter more often with a k&n? I thought k&n was superior to any oem air filters..
Old thread but I will answer anyway.
The OEM filter is not just a paper filter, but also a charcoal filter. It is quite restricting, but also superior filtration. The K&N Drop in gets rid of the charcoal and opts for paper only. It does allow for better breathing but will get dirty quicker and at that point dust/dirt particles will get pushed with the air through into your intake---hence, change it more often.