[Marsch52]

I was wondering if anyone else has opened up the air box on a '08 323i? I found the normal pleated filter, about 1.5 inches thick and a weird polygon shape. Then I saw another white pleated filter, that sits between the air filter and the MAF? Is that second filter supposed to be there?

Has anyone else seen this? What would happen if this "second" filter were removed?

[Marsch52]

Ok, so I got nosy and pulled the air box out of the car again and decided to have a closer look. I took pictures. The first picture is through the opening at the Mass Airflow sensor end and you can see the white pleated filter. The second picture is the white filter on the left. It looks permanent. No way to replace it. And the last picture shows both halves of the air box with the new K&N filter. Which by the way seems to make a big difference when it comes to throttle response. My car alway felt like it was not "breathing" properly, it sure seems to now.

So, anyone have any idea why we have the white filter?

[323d]

that white one is the carbon filter.. just a thing for north america emisson standards.. (euro models dont have the carbon filter)....there is DIY guide on how to remove it..

btw, dont do that mod if you are leasing!

http://www.e90post.com/forums/showthread.php?t=21590

[Marsch52]

Thanks 323d...

You are a fountain of information. I will have a look at that and see if it is worth removing. Any ideas if it causes any grief with Air Care?

[ctgazer]

i think people remove it just to increase airflow

[Marsch52]

And for those who over oil their K&N here is a cleaner that really works and is safe to use. Just remember with the K&N, do not over oil, let them sit out in the open for 24hrs to drain if you think you have over oiled. I have used K&N for over 20 years and never had a problem.

[IMG]file:///C:/DOCUME%7E1/Marcus/LOCALS%7E1/Temp/moz-screenshot.jpg[/IMG]

[323d]

Originally Posted by Marsch52

Thanks 323d...

You are a fountain of information. I will have a look at that and see if it is worth removing. Any ideas if it causes any grief with Air Care?

haha no problem. If i remember correctly, cars newer than 2001 dont need to be aircared? (correct me if i am wrong)

but it should not be a problem if you remove the carbon filter..


hmmm, i wonder if i can get the k&n filter locally..

[Marsch52]

Just for information, I bought the filter from www.bavauto.com and asked for a K&N for a '08 328, even though I have a 323. Fits like a glove and have them ship it via US Postal Service, you will be rewarded. I found it easier to call 1.800.535.2002 and get the sales guy Chris to help you. Easier than going through the web page.

[Slke46]

Interesting info, I've been trying to find out if it would fit our cars even though its for a 328. I'm assuming with removal of the inner air filter the increased airflow will make a difference.

[Marsch52]

Just swapping out the BMW filter with a K&N filter made a world of difference with mine. It gave better throttle response, felt like the engine was not getting enough air before.

As far as removing the "carbon filter", I have not tried that yet. If you are an "over oiler" on your K&N, might be a good idea to leave the "carbon filter" in to catch any oil, until you have mastered the oiling process.

[Stone Pro]

How hard was it to swap the stock air filter for the K & N? I've read a couple posts where it took close to 2 hours to do this simple mod but that was on a 320d.

[Marsch52]

Less than 15 minutes. The second time it only took me 7 minutes.

Check the first few steps here, right to the point he has it out. Do not do Step 8, because that is where he cuts out the carbon filter.

http://www.e90post.com/forums/showthread.php?t=21590

[Slke46]

Thanks for the info, do you think the 07 323 filter is the same as a 07 328? Going to try it out...

[323d]

Originally Posted by Slke46

Thanks for the info, do you think the 07 323 filter is the same as a 07 328? Going to try it out...

The 323i, and 328i have the same airbox. On your first removal, take your time, the Maf sensor is very delicate *especially at the tip) so make sure you take it slow. (unless you have $280 to spare for a new MAF sensor)....

Make sure you also get the right Torx screw.. cause the screws is easy to get stripped if you use the wrong torx screw.

Just go to the DIY section, there is a simota DIY guide which shows you how to remove the stock airbox. follow that step and you should be fine!


Marsch, did you also reset the ECU after you put in the filter? I know i wont get any performance from this, but I would be interested to buy this if it improves response.Come to one of our meets so i can see!

[Marsch52]

I felt it rght away, but will do the ECU reset this weekend.

[604BrO]

is the 08 323i model the samn as my 323i 07.??.. i tried to get the filter at canadian tire but they only have listed for the 08 not the o7 ...???