went to princeton nj bmw to pu some oil and the filter. 7.95 x7 and 18 for filter. typical prices. figured ehh wtf lets get a new air filter and cabin filters which i never replaced before(cabin) i paid 50.00 for the air filter when later i saw i can get the same thing on fcgroton for 18. and they wanted 75.00 each for the cabin filters so i obviosly said fuck that. question. when i changed the air filter the one i took out didnt even look real dirty so i guess i kinda just wasted my money but i noticed another airfilter attactched to the upper air filter cover housing. does that need to be replaceD?

 

That's the charcoal filter... I took mine out - there has been some debate on this forum about the benefits of removing it. I am a believer that its removal increased response time, power (just enough to be noticeable) and contributed to a slightly more throaty sound. I also get a almost 1.5-2 mpg more without it. Others have said they feel nothing different. Either way it threw no error codes so no biggie here.

 

Don't know who made the fcgroton filter but there are "quality" OEM products that will match the performance of "BMW" parts - Mann comes to mind. You shouldn't be surprised that your dealer parts' prices are (sometimes) considerably higher than a .com etc ... their overhead and pricing structure is different. Since you're probably going to continue doing more regular parts replacement/maintenance you should start cataloging on-line stores that provide you quality parts at decent prices - don't forget about S&H and speed of delivery. You could start with some of the vendors that support the forum.

As far as parts replacement schedules - like your air filter - it may not look "dirty" but begins to lose filtering capability with the first spec of duct that may not be readily visible. Depending on where you drive (industrial pollutants and dirty air are heavier in some places) your air filter should be good for 30K -60K miles or 2-3 years. And if a quick replacement is $20-$30 ... probably well worth it. The under-hood micro filters are available in both active carbon and plain pleated. There is a big difference in price but both are available on line.

Again, you could pick one of the reputable BMW e-stores or one of the forum sponsors. If you go on-line thru the link in my signature you may find additional deals and rebates for your car and other purchases.

 

how did u remove it, it looks like its all one part. do u cut it out?

 

Take a thin flat head screw driver and carefully pry it away from the top of the air box... There are clips holding it in (although some have claimed theirs were plastic welded in)... I was careful and saved it for a re-install if I ever decide I need to...

 

This is from the 'helpful hints' that came along with the K&N replacement air filter: "Some vehicles are equipped with a charcoal barrier that is riveted or otherwise built into the air box. This barrier may look like a secondary air filter, but it is actually part of the emissions system and should not be removed."

 

I got my Cabin air filters from EBay, $20 for BOTH shipped.

 

Yup, and your mattresses have tags on them that say its a Federal offense to remove them.....

No errors, increased gas mileage and no problem passing Ct Emissions. In my understanding it is there to catch any gas fumes that escape... or something like that....

 

Hmm...to go with what a reputed manufacturer prints or to go with someone whose understanding appears vague. Tough call.

Just kidding.

It is after all your car and you can do whatever you want to do with it. (btw, it's not a federal offense to remove the mattress tag if you are the owner/consumer ).