Stock air box

[NJ Drive]

Does anyone know why Toyota uses a double filter system in the air box?
The filter that isn't removable and attached to the upper half of the air box seems redundant.

[Betrivent]

That's a carbon filter, which is, if I recall, to prevent any backfiring from the intake manifold lighting the filter on fire..

.. or something

[1.5]

just replace it and dont worry anymore

[WeeYari]

Originally Posted by 1.5

just replace it and dont worry anymore

What does that have to do with OPs question?

[1.5]

He is asking why they put it in? If you replace it then he wont have to worry so much about why it is there.

[WeeYari]

Originally Posted by NJ Drive

Does anyone know why Toyota uses a double filter system in the air box?
The filter that isn't removable and attached to the upper half of the air box seems redundant.

"While normal air filters serve the purpose of removing particulate matter, such as dirt or debris, from the air entering the air intake manifold, the normal air filter provides little help in preventing evaporative emissions from the intake manifold from entering the atmosphere. Such emissions are a particular problem when the engine is turned off and the intake manifold is hot. This source of air pollution has received considerable attention from the federal and state governments with the goal of reducing such emissions.

To that end, the California Air Resources Board (CARB) which effectively sets the maximum air pollution exhaust standards for all motor vehicles sold in the United States, has passed a regulation which requires that a hydrocarbon trap filter be connected in series with the air intake of most motor vehicle internal combustion engines.

Designs of such a hydrocarbon trap air filter has resulted in a flat-panel hydrocarbon trap filter relatively permanently secured to a downstream section of a conventional OEM closed air box, to inhibit tampering, with a conventional flat panel air filter releasably secured to an upstream section of the closed air box."

[WeeYari]

Originally Posted by 1.5

He is asking why they put it in? If you replace it then he wont have to worry so much about why it is there.

In that case, don't you mean to say remove it instead of replace?

[cali yaris]

I think he means replace the whole intake?

[CrankyOldMan]

Originally Posted by WeeYari

"While normal air filters ...

Designs of such a hydrocarbon trap air filter has resulted in a flat-panel hydrocarbon trap filter relatively permanently secured to a downstream section of a conventional OEM closed air box, to inhibit tampering, with a conventional flat panel air filter releasably secured to an upstream section of the closed air box."

^ This. It's not replaceable because it's not supposed to be removed, ever. That said, removing any *ahem* restrictions between the intake mouth and cylinders will improve airflow to the engine.

[NJ Drive]

Originally Posted by WeeYari

"While normal air filters serve the purpose of removing particulate matter, such as dirt or debris, from the air entering the air intake manifold, the normal air filter provides little help in preventing evaporative emissions from the intake manifold from entering the atmosphere. Such emissions are a particular problem when the engine is turned off and the intake manifold is hot. This source of air pollution has received considerable attention from the federal and state governments with the goal of reducing such emissions.

To that end, the California Air Resources Board (CARB) which effectively sets the maximum air pollution exhaust standards for all motor vehicles sold in the United States, has passed a regulation which requires that a hydrocarbon trap filter be connected in series with the air intake of most motor vehicle internal combustion engines.

Designs of such a hydrocarbon trap air filter has resulted in a flat-panel hydrocarbon trap filter relatively permanently secured to a downstream section of a conventional OEM closed air box, to inhibit tampering, with a conventional flat panel air filter releasably secured to an upstream section of the closed air box."

This is EXACTLY the explanation I needed. Thank you!!

[1.5]

Originally Posted by cali yaris

I think he means replace the whole intake?

this

[NJ Drive]

Originally Posted by 1.5

He is asking why they put it in? If you replace it then he wont have to worry so much about why it is there.

You'd be surprised how often an aftermarket part makes little to no gain over a massaged factory part, especially on a putt-putt car like the Yaris.

My reason for asking is that I am trying to stay within a certain SCCA ruleset as follows:

13.10 ENGINE AND DRIVE TRAIN
A. The engine air filter element may be removed or replaced provided
the air flow path remains as originally designed (i.e., no additional
openings). No other components of the air induction system may be
removed, replaced, or modified.

[Jason@SportsCar]

Originally Posted by NJ Drive

You'd be surprised how often an aftermarket part makes little to no gain over a massaged factory part, especially on a putt-putt car like the Yaris.

My reason for asking is that I am trying to stay within a certain SCCA ruleset as follows:

13.10 ENGINE AND DRIVE TRAIN
A. The engine air filter element may be removed or replaced provided
the air flow path remains as originally designed (i.e., no additional
openings). No other components of the air induction system may be
removed, replaced, or modified.

Sounds like a DS Type R issue.

[NJ Drive]

Originally Posted by Jason@SportsCar

Sounds like a DS Type R issue.

Except that my airbox WILL be closed!

[Nicfin]

Maybe it is on there as a backup because of the crappy airbox latches and filter setup. I am not too impressed with the way the airbox/filter system are designed as compared to my older toyotas. The Yaris has a clam shell design with the two latches that just doesn't seem secure. After I bought mine, I actually discovered that one latch was not in the closed position and the airbox was partially cracked open. I am glad the other filter was there.

Also, the latches secure in the opposite direction from on another and I guess the last person to put in the filter wasn't paying attention because I admit it is not intuitive. I had to sort of fight with mine to get it closed when I put in the new filter.

[WeeYari]

^ did you not read post#6?

[Nicfin]

Originally Posted by WeeYari

^ did you not read post#6?

I did quickly, but I read it again. California regulators actually helped me out in my air filter mishap. How about that?

[why?]

carb makes the anti christ look like a good guy.