Air filter above the air filter?? - Toyota Yaris Forums

Shinare · 06-13-2013, 01:33 PM

When changing out my air filter the other day I noticed when I poened up the OEM air box there was a thinner darker filter above the main filter up inside the top part of the box. Does that need to be there? It looks very dirty and wondering if I need to replace it or take it out.

RedRide · 06-13-2013, 01:40 PM

That is pat of the air pollution prevention. It prevents gas fumes from venting into the atmosphere .

Strangely enough, experiments in removing it (and doing nothing else) seems to make little difference in performance and even at that, only in the extreme top end if anything.
It actually allows much more air flow to the engine than you would imagine it would

BTW, it is not dirty. It supposed to be grey in color.

I would leave it in.

Kaotic Lazagna · 06-13-2013, 01:58 PM

Someone on a Lexus forum played with it. Dyno'd their car with the carbon trap (I think that's what that piece is called) and without....engine made less power with it off. lol

Betrivent · 06-13-2013, 03:54 PM

^ because science.

RedRide · 06-13-2013, 04:15 PM

It should be remembered that it is indeed a "hydrocarbon trap" and not an air trap.

Shinare · 06-14-2013, 03:47 PM

Thanks, I was just wondering seeing as how all these aftermarket intakes probably don't have one, just wondering if I needed it since it looked very "dirty". Seeing as how that's how it is supposed to look, I'm fine with it. heh :)

CrankyOldMan · 06-14-2013, 04:23 PM

It's a charcoal/carbon filter. Technically, removing it is in violation of EPA regulations, blah blah blah, but in reality it could make a very small difference in the intake airflow. I would also take the dyno test with a grain of salt, unless they did 3+ pulls in a row for each configuration and compared the average of the two.

06-13-2013, 01:33 PM	#1
Shinare Bronze bombshell yaris Drives: 09 Yaris HB 3door Join Date: Sep 2010 Location: Oklahoma City, OK Posts: 641	Air filter above the air filter?? When changing out my air filter the other day I noticed when I poened up the OEM air box there was a thinner darker filter above the main filter up inside the top part of the box. Does that need to be there? It looks very dirty and wondering if I need to replace it or take it out. __________________ Now I drive a CARMINE RED METALLIC 09 Yaris 3-door!! I'm Back!!! WooHoo!! Mods done so far: Tinted windows, Viper 211HV Remote Keyless Entry, Atoto Android headunit, backup camera, steering wheel controls Before it was totaled I drove a 2007 Black Sand Pearl 3 Door Lift-Back M/T with 49k miles. Stock Everything except for black tint, all red badges, red dash, and stealth garage door opener. Ultra-Gauge mounted on steering wheel. A1 Electric MES Central Locks and Avital 3100 Alarm system.

06-13-2013, 01:40 PM	#2
RedRide Drives: '09 Yaris carmine red 2d HB Join Date: Jun 2009 Location: Middletown, NY Posts: 1,501	That is pat of the air pollution prevention. It prevents gas fumes from venting into the atmosphere . Strangely enough, experiments in removing it (and doing nothing else) seems to make little difference in performance and even at that, only in the extreme top end if anything. It actually allows much more air flow to the engine than you would imagine it would BTW, it is not dirty. It supposed to be grey in color. I would leave it in. Last edited by RedRide; 06-13-2013 at 04:48 PM.

06-13-2013, 04:15 PM	#5
RedRide Drives: '09 Yaris carmine red 2d HB Join Date: Jun 2009 Location: Middletown, NY Posts: 1,501	It should be remembered that it is indeed a "hydrocarbon trap" and not an air trap. Last edited by RedRide; 06-13-2013 at 04:27 PM.

06-14-2013, 03:47 PM	#6
Shinare Bronze bombshell yaris Drives: 09 Yaris HB 3door Join Date: Sep 2010 Location: Oklahoma City, OK Posts: 641	Thanks, I was just wondering seeing as how all these aftermarket intakes probably don't have one, just wondering if I needed it since it looked very "dirty". Seeing as how that's how it is supposed to look, I'm fine with it. heh :) __________________ Now I drive a CARMINE RED METALLIC 09 Yaris 3-door!! I'm Back!!! WooHoo!! Mods done so far: Tinted windows, Viper 211HV Remote Keyless Entry, Atoto Android headunit, backup camera, steering wheel controls Before it was totaled I drove a 2007 Black Sand Pearl 3 Door Lift-Back M/T with 49k miles. Stock Everything except for black tint, all red badges, red dash, and stealth garage door opener. Ultra-Gauge mounted on steering wheel. A1 Electric MES Central Locks and Avital 3100 Alarm system.

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06-13-2013, 01:58 PM	#3
Kaotic Lazagna View User's Garage Drives: '14 GT86, '08 Vitz Join Date: Dec 2006 Location: Central Valley, CA Posts: 9,873	Someone on a Lexus forum played with it. Dyno'd their car with the carbon trap (I think that's what that piece is called) and without....engine made less power with it off. lol

06-13-2013, 03:54 PM	#4
Betrivent Not quite a noob Drives: e46 325 Join Date: Jul 2009 Location: edmonton Posts: 1,408	^ because science.

06-14-2013, 04:23 PM	#7
CrankyOldMan 2ZR swap. DO IT! Ask how! View User's Garage Drives: 09 Meteoric Metallic HB Join Date: Feb 2011 Location: West Michigan Posts: 2,333	It's a charcoal/carbon filter. Technically, removing it is in violation of EPA regulations, blah blah blah, but in reality it could make a very small difference in the intake airflow. I would also take the dyno test with a grain of salt, unless they did 3+ pulls in a row for each configuration and compared the average of the two.