Charcoal Filter Purpose?

[F80Dreamer]

Tried to do a search to find the answer but couldn't find it...I did a light mod on my car this weekend (replaced stock filters with BMC drop ins, removal of charcoal filters). Really like the sound difference and the sound of the turbos...but not really sure what the role is of the charcoal filter? Just another added layer of protection to not let any particles through? I am assuming it was there for a good reason...

[SO17]

Emissions. US (and possibly others) have them, UK cars don't.

[stevenc]

Absorb gas fumes. European cars dont have them since their emissions standards are different.

[SloTUrtle]

Removing this won't void any warranties will it??

[schnell1982]

Originally Posted by SloTUrtle

Removing this won't void any warranties will it??

Its a North America emission part.
I have never heard of anyone having a warranty related issue.
It will not set a "check engine" light or alter the way the car performs.
Probably one of the first things everyone removes

[M4RAUDR]

Prevents back flow of exhaust fumes out of intake. Completely ridiculous feature - remove them promptly.






.

[CaryTheLabelGuy]

It is there to stop positive crankcase venilation, which is routed back into the intake, from venting to atmosphere. It's main job is to catch microscopic oil droplets and any fuel contamination that may have blown by the piston rings and into the crankcase (the main cause of oil contamination).

[swifty]

Originally Posted by CaryTheLabelGuy

It is there to stop positive crankcase venilation, which is routed back into the intake, from venting to atmosphere. It's main job is to catch microscopic oil droplets and any fuel contamination that may have blown by the piston rings and into the crankcase (the main cause of oil contamination).

So does this mean it's a good for the car or for emissions?

Does anyone have a link to the filters?

[CaryTheLabelGuy]

Originally Posted by swifty

So does this mean it's a good for the car or for emissions?

Does anyone have a link to the filters?

Any oil (in this case, from the crankcase) in the combustion chamber is a bad thing for the engine in that oil present in the combustion chamber lowers the detonation threshold and enough of it can easily cause knock. Having crankcase venilation routed into the intakes means 99.999% of the crankcase venilation is going to make its way back into the combustion chambers to be burned (for emissions). Those charcoal filters are there to stop the .000001% that might make it to the atmosphere.

Using an Oil Catch Can eliminates the need to route PCV into the intakes. The charcoal filters are more of a hindrance to performance and are only there for the stock PCV setup.

[aboulfad]

We were discussing flashing Euro DME onto our US DME and the removal of "something" from the intake silencer, is part #2 & 4 in https://www.etkbmw.com/bmw/EN/search...M4/USA/13_1612 that you refer to as the "charcoal filter" and that you remove completely?

EDIT: I am referencing above the air filter element, the "charcoal filter" that is discussed in this thread and removed by some cannot be easily found in ETK.

[Celestion]

Originally Posted by aboulfad

We were discussing flashing Euro DME onto our US DME and the removal of "something" from the intake silencer, is part #2 & 4 in https://www.etkbmw.com/bmw/EN/search...M4/USA/13_1612 that you refer to as the "charcoal filter" and that you remove completely?

To those that say UK/ECE don't have it, ETK shows them as installed parts, and if you search the m3 cutters site, they talk about replacing them and servicing/buying them... so unsure where people find information that says it is NOT installed outside of North America.

hmmm. Those look like the normal air filters that indeed should not be removed.

Here is a pic of my liners for comparison (part #s: 70553698, 70553739)

[Celestion]

What I find odd is that the part numbers don't show up for me in etk or realoem. I also haven't been able to find any documentation about these filters, even in ISTA.

[aboulfad]

Originally Posted by Celestion

hmmm. Those look like the normal air filters that indeed should not be removed.

Here is a pic of my liners for comparison (part #s: 70553698, 70553739)

Tx for your reply, now I am really confused! Btw your part nbs aren't BMWs, well at least can't find them in ETK Where were those parts you removed, was there something else in the intake silencer housing?

ISTA only list air filter elements, search air filter and you will get a repair/replace doc.

Here's what hakcar wrote which implies there's something else...

edit: oh, and the "air filter element" in the diagrams on realoem and etkbmw is the main filter, not the extremely thin fibrous filter that clips on to the (top?) housing of the actual panel. Running without the "air filter element" would indeed be pretty silly

[Celestion]

Originally Posted by aboulfad

Tx for your reply, now I am really confused! Btw your part nbs aren't BMWs, well at least can't find them in ETK so what part is being removed, please provide a link from ETK online. Where were those parts you removed, was there something else in the intake silencer housing?

ISTA only list air filter elements, search air filter and you will get a repair/replace doc.

Here is a link and pic of the non-optional air filter. It is housed in the same air box as the liner and sits just beneath it.

[aboulfad]

Originally Posted by Celestion

Here is a link and pic of the non-optional air filter. It is housed in the same air box as the liner and sits just beneath it.

Ok thats the part I've been talking about that now we all agree shouldn't be removed. I was confused thinking they were the same part while there's another part the ETK diagrams don't show or list... weird!

[Celestion]

Originally Posted by aboulfad

Ok thats the part I've been talking about that now we all agree shouldn't be removed. I may have been confused thinking they were the same part while it seems there's another part the ETK diagrams don't show or list...

Yep. I think our inability to explicitly find this carbon liner thingy in BMW's part catalog is strange. I have a hypothesis though. The liner clips into the top of the air box housing. Maybe the American housing comes with the part installed and the euro one simply comes without it.

Edit: theory confirmed...

Euro housing mass = 0.990kg

NA housing housing mass = 1.170kg

[aboulfad]

Originally Posted by Celestion

Yep. I think our inability to explicitly find this carbon liner thingy in BMW's part catalog is strange. I have hypothesis though. The part clips into the top of the air box housing. Maybe the American housing comes with the part installed and the euro one simply comes without it.

Edit: theory confirmed...

Euro housing mass = 0.990kg

NA housing housing mass = 1.170kg

Nice try, but you gotta use ETK desktop or online, not realoem ;-), both ECE/US left/right intake silencer housing is 1.4kgs/0.99kgs! I have ETK 04/2017. The P/N are the same so they cant have different configurations. Mystery continues for this elusive charcoal filter, I'll ask my dealer tomorrow !

[Celestion]

Originally Posted by aboulfad

Nice try, but you gotta use ETK desktop or online, not realoem ;-), both ECE/US left/right intake silencer housing is 1.4kgs/0.99kgs! I have ETK 04/2017. The P/N are the same so they cant have different configurations. Mystery continues, I'll ask my dealer tomorrow !

Hmm, I'm finding the same regional weight differences for the air intakes in ETK though.

NA - right air intake

Application list for the NA part number.

EU - right air intake

Application list for the EU part number.


Strangely, the NA P/N approved vehicle list contains only NA cars, but the EU P/N list allows for the EU part to be used in EU AND NA cars. This is super confusing lol!!

[aboulfad]

Originally Posted by Celestion

Hmm, I'm finding the same regional weight differences for the air intakes in ETK though.

NA - right air intake

EU - right air intake

You have there two P/N there are not consecutive and not belonging to one vehicle... (491, 268)
For an M4 F82 US and do the same for ECE:
- Left is : https://www.etkbmw.com/bmw/en/parts/...ht/13717846269
- Right is: https://www.etkbmw.com/bmw/en/parts/...ht/13717846268

[Celestion]

Originally Posted by aboulfad

You have there two P/N there are not consecutive and not belonging to one vehicle... (491, 268)
For an M4 F82 US and do the same for ECE:
- Left is : https://www.etkbmw.com/bmw/en/parts/...ht/13717846269
- Right is: https://www.etkbmw.com/bmw/en/parts/...ht/13717846268

That's correct. I'm comparing the weights of the "NA" and "EU" right air boxes. My guess is that the NA unit contains the carbon liner whereas the EU unit does not, hence my interest in each of their weights.

liner (0.095kg) + right "EU" airbox, presumably linerless (0.99kg) = 1.085 kg

"NA" airbox = 1.170kg

So the EU airbox with the liner weight added to it, is about equal to the NA airbox alone. This seems like a good approach to me. Maybe I'm not understanding something fundamental lol.

[CanAutM3]

Originally Posted by Celestion

Hmm, I'm finding the same regional weight differences for the air intakes in ETK though.

NA - right air intake

Application list for the NA part number.

EU - right air intake

Application list for the EU part number.


Strangely, the NA P/N approved vehicle list contains only NA cars, but the EU P/N list allows for the EU part to be used in EU AND NA cars. This is super confusing lol!!

Seems like you're onto something here

[aboulfad]

Originally Posted by Celestion

That's correct. I'm comparing the weights of the "NA" and "EU" right air boxes. My guess is that the NA unit contains the carbon liner whereas the EU unit does not, hence my interest in each of their weights.

I think one of us isn't getting the other if you do that, do it for the same car in different markets, don't choose a right pn for an M4 GTS/M3 and then use M4 for left pn.

So choose 268/269 not 268/491, and then you'll see that ECE/US for the consecutive pn are the same weight.

Furthermore, 268/269 are 1.4/0.99, 491/492 are 1.55/1.170 so the new combo 491/492 seem to be a bit heavier but still the same on ECE cars.