Charcoal Filter Delete?

[Bimmer-Bob]

Is this legit? I spent way too much time today over at E90Post (which I don't recommend, btw) and it seems like every tool that wants to turn their 328i sedan into a racecar is doing this. I get the theory and all, but it really seems sort of inconsequential.

The only reason I ask is because I'm gonna be in the airbox anyway to install the Performance intake and I wonder if I ought to just go ahead and remove the damn thing.

I also found it interesting that it's pretty much only N52 folks talking about this "mod" - never seen anyone with an N54/5 mention the need to do this. And then I found a huge thread about it on one of the M5 boards.

WTH? Do I, or don't I?

[Raine]

Originally Posted by Bimmer-Bob

Is this legit? I spent way too much time today over at E90Post (which I don't recommend, btw) and it seems like every tool that wants to turn their 328i sedan into a racecar is doing this. I get the theory and all, but it really seems sort of inconsequential.

The only reason I ask is because I'm gonna be in the airbox anyway to install the Performance intake and I wonder if I ought to just go ahead and remove the damn thing.

I also found it interesting that it's pretty much only N52 folks talking about this "mod" - never seen anyone with an N54/5 mention the need to do this. And then I found a huge thread about it on one of the M5 boards.

WTH? Do I, or don't I?

I also spend a little too much time on the E90 forums =(

As for gains, it increases throttle responsiveness a little from the low end. I think it's worth it though if you're keeping the stock air box, considering it's free and only takes like 30 minutes. More free flowing air can't be a bad thing.

The charcoal filter only exists in US/Canadian cars though so keep that in mind. The Euro/other parts of the world cars don't even have it.

[Sarracino89]

Could you guy's link me to one of these diy threads, my search turned up nothing, maybe I am just using the wrong search terms. I just got my new drop in filter and want to take out the carbon filter at the same time. TIA

[Greenkirby21]

Originally Posted by Sarracino89

Could you guy's link me to one of these diy threads, my search turned up nothing, maybe I am just using the wrong search terms. I just got my new drop in filter and want to take out the carbon filter at the same time. TIA

there is not DIY i think. all you do is cut it out.

[zkeeper]

Guys...go back to the main list, and check out the request #7 I put in a few days ago, titled: AIRBOX CARBON FILTER REMOVAL.

Raines gave me a great link...with pixs etc of how it is done. One must remove the airbox which is not hard once you get the hang of it. Be careful on the airsensor connection not to break the little tiny tab holding it together...its located aft of the whole airbox right on top of the tube leading to manifold. Once box is out, by removing the 4 little screws holding the front airplenum, and you loosen the hose clamp on the tubing, and remove the two bolts near driver fender, it lifts and twists out.

Remove the screws holding the box and lid together, and inside you will find the carbon filter MOLDED to the lid. It has to be cut out, then cleaned at all edges where it was attached and then re-assembly as normal.

I am in process of doing this. My guys at dealer and my tech it does not affect warranty, as it is before the air sensor. They said, it will probably give the air sensor a bit of an extra rush thus ask for more gas which gives the motor a little more free feel. Nothing great, but it did do well for my Z4si last summer.

Check out the post...and see Rainse connection he lists...nice pix as well.

[Bimmer-Bob]

I don't know - I'm not really too keen on cutting out the charcoal filter. If it were a simple drop-in, I could give it a go without and it would be easily reversible.

Also, I'm not really convinced that a charcoal filter meant to prevent the passive backflow of hydrocarbons is necessarily restrictive to the normal movement of air under pressure.

Finally, I have to say I'm just turned off by the idea that the combination of a drop-in filter, removal of this charcoal filter, and the addition of scoops amounts to any measurable performance gain (most of the guys advocating removal of the charcoal filter are in fact advocating for this combination). There is simply NO WAY that scoops do absolutely anything - it sort of makes me doubt the whole thing altogether.

Just my two cents.

[Milligan]

It is probably all placebo. Put the thing on a dyno before and after, I can almost guarantee there would be no difference. If there is, it wouldn't be noticeable in the seat.