Air filter,primary and secondary

[floydisrock]

Anyone replace the primary and secondary air filters?
Anyone have the mileage interval?
I ordered some wix secondaries,but the primary's seem mighty expensive.:bs:

[Kaotic Lazagna]

Primary and secondary? Do you mean the carbon trap?

[Yaris Hilton]

What?

[WolfWings]

Yeah... the Yaris only has one air filter for the engine, and one for inside the A/C in the cabin. There's no primary or secondary to it, just one filter for each entirely-seperate purpose. And both are bone-simple to change and cheap as dirt.

[floydisrock]

http://www.car-stuff.com/store/?N=11805+4294963156+1725+11921+9157

I guess I ordered 4 wix primary filters at about $10 each.
I kept running into the listing for secondary filters,and couldn't figure out what they were talking about.
I'm guessing maybe it's the plastic cover?
The filter comes out easily,but I imagine it's easy to crack the hinge/housing.
Just a heads up.

[Yaris Hilton]

I haven't looked in my air box yet. I've seen filters before that had a foam filter to catch the bulky coarse dirt before the air goes through the finer paper filter that removes the smaller dirt particles but clogs faster.

[BLH]

The break down on ToyoDIY.com actually shows a sub filter in the top of the housing.
I never even looked in the top part for a second filter.

[CTScott]

The part shown on ToyoDiy is a white mesh filter that is probably there to keep anything that gets freed up when the filter is changed from making it to the MAF sensor. The EPC doesn't show it as being a separate part from the air box, so it is probably not intended to ever be replaced.

[b_hickman11]

It's called a Carbon Trap.

[RedRide]

I just replaced my air filter with a K&N.

I must admit that I'm a bit piuzzled by this secondary fillter.
I could understand if airflow was from top to bottom as it would keep anthing from "falling" into the intake.

However, since air flow is from bottom to top, it doesn't make much sense to me.
What is ment by it being a "carbon trap"?

[eric81]

Carbo trap keeps stuff from going into the engine that doesn't belong, and stuff from leaving the engine the wrong way. Pointless, IMO. I took mine out right away, and had no problems. Take yours out, and try blowing through it. It's kinda hard. Now, imagine your engine going through that same strain. The less work the engine does to create power, the more power it has to put to the ground.

[RedRide]

Carbo trap keeps stuff from going into the engine that doesn't belong, and stuff from leaving the engine the wrong way. Pointless, IMO. I took mine out right away, and had no problems. Take yours out, and try blowing through it. It's kinda hard. Now, imagine your engine going through that same strain. The less work the engine does to create power, the more power it has to put to the ground.

Isn't that what the "main" air filter is for? If the air filter is filtering as it's designed to do, what is the purpose of the secondary?

I agree that it limits air flow. Perhaps that's precisely what it's for?
Maby it's part of toyta's "tuning" to limit performance to increase MPG?

[YarisSedan]

I think its there just as a precation. Which is why you have a noticible difference swapping to a performance intake verses stock. Because there is so much restriction to begin with.

[RedRide]

Ok.... I just came from the Toyota dealer. I got my initial oil change using the VIP card they gave me. They are right down the road and have been changing the oil on my Celica for years. With a cupon it's realtively cheap also.

Anyway, I just happen to run into the service manager and I asked him about the purpose of the secondary air filter.

Now, he has been there for years (a major dealer in the NE) and we have had a few conversations in the past.
However, as far as the secondary filter, he admitted to me that he really didn't have clue about its purpose.

When I ran by him the things I heard it might be for (carbon trap etc) he when on to say that he has heard all that but, he has never heard or read anything official from Toyota to indicate what it was for and as far as he knows, it has nothing to do with emissions, etc as some suspect.

So, the mystery continues.

BTW, the K&N filter definately made a dfference in throttle response and is well worth it. :smile:

[b_hickman11]

Carbo trap keeps stuff from going into the engine that doesn't belong, and stuff from leaving the engine the wrong way. Pointless, IMO. I took mine out right away, and had no problems. Take yours out, and try blowing through it. It's kinda hard. Now, imagine your engine going through that same strain. The less work the engine does to create power, the more power it has to put to the ground.

More Power=Lower MPG

[RedRide]

More Power=Lower MPG

Exactly my point in a previous post.
I suspect its only purpose is to increase MPG.

[RedRide]

I just found this and it seems to shed some light on the matter:
A C&P---

".....;I have to rant...I love how everyone calls the carbon filter a "secondary air filter" even though it's not an air filter at all. It just keeps gas fumes from leaving the engine and adding to pollution. Those fumes get trapped in the carbon and then sucked back into the engine when you start it back up. So by removing the carbon filter, everyone's just venting those fumes into the atmosphere instead of using them when the engine is running. Might as well leave the gas cap off too. Personally, when I pay for all that gas I like to use it in running the engine rather than just letting it evaporate into the air."

I then read that this was done mainly to apease Califorinia's stricker emissions standards.

If all this is true, removing it will do no harm and will not effect emissions tests, except maby in California.

[Kaotic Lazagna]

So would it really be worth it to remove it and cause more pollution? I doubt it that it would cause a noticeable power increase.

[1stToyota]

You might get a little more power w/ it removed...until the MAF quickly learns to adjust for the extra FLOW, unless maybe you're always at WOT...and it's nice insurance to have in the event you have an oiled filter installed.

[Kaotic Lazagna]

Nope, still using Toyota paper filters. Eh, I might take it off, but I don't think I'll have the time to since I start school again soon.

[slvryaris]

If you pop the lid on the intake what is the screen like filter at the top part of the air box. Is this what everyone is talking about as the secondary filter??

[b_hickman11]

yes

[RedRide]

You might get a little more power w/ it removed...until the MAF quickly learns to adjust for the extra FLOW, unless maybe you're always at WOT...and it's nice insurance to have in the event you have an oiled filter installed.

The MAF sensor simply moitors air flow and the ECU/PCM adjusts fuel flow acordingly to manrtain a proper air/fuel mixture. Otherwise it will be running lean every time you increase airflow.

Anyway, from what I can gather from reading, it seems that removing it ("the carbon trap") does not really increase perfomance to any worth while degree.

BTW, I never had a problem with a K&N filter in all the years I have used one. :smuile:
The one problem I did have with a MAF was on a car that didn't even have a K&N in it and was running the stock filter.
If I had a K&N installed, would this now have been blamed on it?
We all have to be careful not to jump to false conclusions.

Also, even Toyota a sells oiled, K&N type filters... it's called a TRD filter so even Toyota has no problem with them.

Some very interesting info. Be shure to watch all the videos.
http://www.knfilters.com/MAF/massair.htm

[1stToyota]

The MAF sensor simply moitors air flow and the ECU/PCM adjusts fuel flow acordingly to manrtain a proper air/fuel mixture. Otherwise it will be running lean every time you increase airflow.

Anyway, from what I can gather from reading, it seems that removing it ("the carbon trap") does not really increase perfomance to any worth while degree.

BTW, I never had a problem with a K&N filter in all the years I have used one. :smuile:
The one problem I did have with a MAF was on a car that didn't even have a K&N in it and was running the stock filter.
If I had a K&N installed, would this now have been blamed on it?
We all have to be careful not to jump to false conclusions.

http://www.knfilters.com/MAF/massair.htm

Yes, you can clog up your paper element, run w/o a filter, or use an oiled filter, but the MAF will take its measurments to help keep the oiled filter guy from actually "boiling the tires at 55mph" (true story)...oh, he can claim it, but it's not actually reality, just all in his mind.

BTW, I never had a problem with any of my K&N filters and CAI systems, but I've seen lots of dirty MAF meters, oiled & paper filters alike. So I don't need to be careful, I've seen actual proof of dirty MAF meters and confirmed datastream info (calculated engine loads, before and after a cleaning) :iono:

Oh, and in a recent magazine (MotorAge?...can't really remember) they had an article on MAF meters and oiled elements. I noticed their claim that many automakers will not honor warranties if oiled filter is installed.

[RedRide]

......Oh, and in a recent magazine (MotorAge?...can't really remember) they had an article on MAF meters and oiled elements. I noticed their claim that many automakers will not honor warranties if oiled filter is installed.
This just illustrates the misinformaton out there as Toyota sells an oiled filter. So, how can they not honer a warrenty?
We all know how some dealers tend to not want to honor warrenties and look for excuses.

There has never been a doumented case where an oiled filter caused a MAFS to fail.
The worst case senerio can be where a filter is over oiled. Even then it can be cleaned.
A dirty MAFS does not equel a "failed" MAFS.

A MAF can fail for various reasons and just because an oiled filter is installed, does no mean the filter is at fault.

[1stToyota]

This just illustrates the misinformaton out there as Toyota sells an oiled filter. So, how can they not honer a warrenty?
We all know how some dealers tend to not want to honor warrenties and look for excuses.

There has never been a doumented case where an oiled filter caused a MAFS to fail.
The worst case senerio can be where a filter is over oiled. Even then it can be cleaned.
A dirty MAFS does not equel a "failed" MAFS.

A MAF can fail for various reasons and just because an oiled filter is installed, does no mean the filter is at fault.

I didn't name any makes, just remembering something written in a professional auto repair mag--the average Joe will never read it, it's mailed to auto repair shops for free.

Never said MAF sensors were *ruined* with paper or oiled filters installed, said I've seen lots of dirty sensors.