Charcoal intake filter removal testing & RESULTS

[mycrors7]

Originally Posted by ROFL it's Waffle

I don't live in California though. Does it NEED to have an emissions label to be considered an emissions piece-part? I just figured some idiotic policy got enforced and some blanket statement addressed it.. but there's a dedicated label? Learn something new every day.

Ironically when I had my boosted S2K, the new owner (who lives in California) asked to see the label on the procharger for the CARB serial number... and sure enough, it was there (I had no idea).

Yes. Your hood has an emissions label noting everything your vehicle is equipped with to pass emissions. If it’s not on that label, then it will have an EO(executive order) number on it. The ONLY exception to the label is your EVAP and PCV system, which are federally required on all vehicles and are not mentioned on any labels and don’t require any EO.
The charcoal filter has nothing on it, isn’t mentioned in the emissions label and isn’t mentioned in any federal or state emissions document for 2022 emissions.

I can’t speak for upcoming years, but 2022 models can safely rip that filter out and it won’t affect any legalities for smog.

[Ultramaroon]

That's interesting. It costs money so, if not mandated, why does it exist?

[NoHaveMSG]

Had anyone cut it open? Are we sure it’s a charcoal filter?

Doesn’t make sense to be where it is. Most evap purge is held back by the evap purge solenoid on the IM.

[Ogt]

I still have mine…. I believe… forgot to toss it so if @Tcoat allows it<3….
I will post pictures of contents.

If it’s not required then perhaps it’s some Subaru green-earth-virtue move? Just speculating based off of the emails I get now.

[Ultramaroon]

Originally Posted by Ogt

I still have mine…. I believe… forgot to toss it so if @Tcoat allows it<3….
I will post pictures of contents.

If it’s not required then perhaps it’s some Subaru green-earth-virtue move? Just speculating based off of the emails I get now.

No way. They've been ubiquitous since the mid '00s, and it's ALWAYS about money.

[Chrisz5z]

Originally Posted by NoHaveMSG

Had anyone cut it open? Are we sure it’s a charcoal filter?

Doesn’t make sense to be where it is. Most evap purge is held back by the evap purge solenoid on the IM.

photo some one else took of it cut open...

[MyHybridBurnsGasAndTires]

Originally Posted by Ultramaroon

That's interesting. It costs money so, if not mandated, why does it exist?

i'm not sure how strongly it's mandated but it could be part of the general effort to reduce emissions by minimizing any ways for the engine to 'leak' gasses/vapors/ect.


some brands did away with dipsticks in pursuit of this but im glad not all of them followed suit.

Originally Posted by NoHaveMSG

Had anyone cut it open? Are we sure it’s a charcoal filter?

Doesn’t make sense to be where it is. Most evap purge is held back by the evap purge solenoid on the IM.

the OP mentioned it but didnt link it...according to EE these filters are designed to collect emissions coming back out of the intake system (manifold, ect), basically when the car is turned off. seems like it would account for vanishingly small benefits but some engineer managed to convince an accountant that it's worth it.

[mycrors7]

Originally Posted by Ultramaroon

That's interesting. It costs money so, if not mandated, why does it exist?

its not mandated yet

they might be phasing them in. a lot of emissions components that are required now were slowly phased in and were on vehicles that never really required them.

a big portion of people who havent studied smog emissions properly or done enough research wouldnt know it's not required.

very similar things happen with an AOS and their legalities. on paper, an AOS, if full sealed(doesnt vent to atmosphere and recirculates back into the oiling system), does not require an EO and is legal to install on engines.

[NoHaveMSG]

Originally Posted by MyHybridBurnsGasAndTires

i'm not sure how strongly it's mandated but it could be part of the general effort to reduce emissions by minimizing any ways for the engine to 'leak' gasses/vapors/ect.


some brands did away with dipsticks in pursuit of this but im glad not all of them followed suit.

the OP mentioned it but didnt link it...according to EE these filters are designed to collect emissions coming back out of the intake system (manifold, ect), basically when the car is turned off. seems like it would account for vanishingly small benefits but some engineer managed to convince an accountant that it's worth it.

I get the idea behind it. It’s just being primarily DI and with the evap purge it seems overkill. If it doesn’t have an EO and isn’t in the emission warranty statement then I dunno. Strange to have it. I work in small non road equipment and file our EPA certification ever year. I’d imagine automotive side is several orders of magnitude more then what I have to deal with.

[Ultramaroon]

Originally Posted by MyHybridBurnsGasAndTires

the OP mentioned it but didnt link it...according to EE these filters are designed to collect emissions coming back out of the intake system (manifold, ect), basically when the car is turned off. seems like it would account for vanishingly small benefits but some engineer managed to convince an accountant that it's worth it.

Haha... I was too lazy to go back after I started thinking about it. I bet there's a blanket VOC emission target. That makes sense. Oh well. One tank fill with an old-school pump valve versus a year of shutdowns without the intake sponge.

[Tcoat]

Originally Posted by Ogt

I still have mine…. I believe… forgot to toss it so if @Tcoat allows it<3….
I will post pictures of contents.

If it’s not required then perhaps it’s some Subaru green-earth-virtue move? Just speculating based off of the emails I get now.

What I would really like to see is one that is pulled out after a couple of thousand miles in dusty conditions. If the main filter is still squeaky clean then the charcoal is indeed chocking it. If the main is dusty and plugged then the charcoal ain't doing squat.

The worst part I see for actual real world condition is that the main is made with pleats to allow for build up but still maintain a larger surface area but that thing is flat negating the benefits.

No way you get a 10HP increase from removing it but if it plugs up quickly while leaving the main trying to suck you can bet you could get a 10hp loss across the whole curve.

[ROFL it's Waffle]

Originally Posted by MyHybridBurnsGasAndTires

the OP mentioned it but didnt link it...according to EE these filters are designed to collect emissions coming back out of the intake system (manifold, ect), basically when the car is turned off. seems like it would account for vanishingly small benefits but some engineer managed to convince an accountant that it's worth it.

I swear I've seen this YT video somewhere.... oh, post 23 of this thread

[ROFL it's Waffle]

Originally Posted by Tcoat

What I would really like to see is one that is pulled out after a couple of thousand miles in dusty conditions. If the main filter is still squeaky clean then the charcoal is indeed chocking it. If the main is dusty and plugged then the charcoal ain't doing squat.

The worst part I see for actual real world condition is that the main is made with pleats to allow for build up but still maintain a larger surface area but that thing is flat negating the benefits.

No way you get a 10HP increase from removing it but if it plugs up quickly while leaving the main trying to suck you can bet you could get a 10hp loss across the whole curve.

I realize my link is for charcoal filters for home HVAC, but I'm sure the same applies to cars. https://enviroklenzairpurifiers.com/...in-air-filter/

Kinda makes me wonder though. If the paper air filter is already considered a consumable, eventually the charcoal filter could also become clogged (and what criteria deems it at the end of its lifespan?)... unless they're thinking there are gases regurgitating out the intake manifold (wouldn't the butterfly valve stop this? I just don't picture air trying to rush out of the intake manifold.

What does the owners manual say about the charcoal filter? Is this considered a forever item, or "change regularly"?

[Tcoat]

Originally Posted by ROFL it's Waffle

I realize my link is for charcoal filters for home HVAC, but I'm sure the same applies to cars. https://enviroklenzairpurifiers.com/...in-air-filter/

Kinda makes me wonder though. If the paper air filter is already considered a consumable, eventually the charcoal filter could also become clogged (and what criteria deems it at the end of its lifespan?)... unless they're thinking there are gases regurgitating out the intake manifold (wouldn't the butterfly valve stop this? I just don't picture air trying to rush out of the intake manifold.

What does the owners manual say about the charcoal filter? Is this considered a forever item, or "change regularly"?

I am glad you quoted because rereading my post from last night I realized it sounds like the charcoal filter is in front of the pleated one.
Very bad phrasing on my part.