Gen 2 Stock airbox Question?

myleshouston · 09-30-2009, 11:35 AM

Hey guys i just got my k&n panel filter yesterday and when i put it in i noticed there is like another filter in the lid of the stock airbox? does anyone know what this is and how to remove it seems like it would just defeat the purpose of the k&n. i tried prying it out but it wouldn't budge do you have to break it to get it out? and if you take it out will it hurt anything? (ie check engine lights, ect.) thanks in advance!

elusive_xb · 09-30-2009, 01:50 PM

pics? are you talking about the mesh stuff thats where the pipe meets the box?

myleshouston · 09-30-2009, 01:54 PM

it sits above the filter and is the exact same size as the filter. it seems to be mesh but also has filter material behind it. it looks like it is riveted in with plastic rivets. sorry no pics right now

elusive_xb · 09-30-2009, 02:00 PM

ok i know what you mean.... let me run out and look at mine ill be right back

ok im back.... ok from what ive been told its kinda like an automotive HEPA filter.... like on a vacuume, that way we xb2 guys can get away with 5000 mile oil changes and not have to worry about it like older cars need it done every 3000 miles....

i may be wrong but thats what i have heard and removing it might mess with your mass air flow plug.... but i donno, id call a dealer

myleshouston · 09-30-2009, 02:11 PM

I see. I guess i will leave it for now it just seems useless cause you would get rid of it anyway with a CAI. I think the 3000 mile oil change is BS made up by the oil company's anyway. my old 99 saab 9-3 recommended 10k oil changes with regular mineral oil.

elusive_xb · 09-30-2009, 02:39 PM

true but im a 2000-2500 oil changer..... i use full synthetic lucas with teflon and restore additive.... i like running fresh and clean but yeah im a car guy and i get board so i change my oil lol

shawnofthedead420 · 09-30-2009, 05:13 PM

i broke that top filter out about 2500 miles ago and havent had a single problem. didnt notice a diference either. just leave it in cause you do have to break it out.

TrevorS · 10-01-2009, 06:02 PM

I removed it same time as I installed my TRD Hi-Flo filter. Figured it was sufficiently restrictive to pretty much nullify the Hi-Flo. Between getting rid of that and the snorkle (plus adding the Hi-Flo), my engine seemed to breath much better.

myleshouston · 10-02-2009, 02:15 PM

What do you mean by snorkel? the tube going down into the bumper? what is that small box on the engine side of the hose behind the airbox?

TrevorS · 10-02-2009, 04:29 PM

That tube (snorkle) doesn't actually go into the fender, it's a loop that comes back up terminating in that plastic intake flare near the battery.

As I understand, that small box is a tuned chamber for the purpose of reducing intake noise (likewise the snorkle). I've no reason to presume the chamber harms performance, but the snorkle definitely does.

awinter · 10-02-2009, 08:04 PM

By removing the carbon filter element (the part riveted in the top of the air box) you have tampered with your emissions system which is illegal (in California). When it comes time to have your car smogged, you may run into issues by not having this part. You can also be cited severely by law enforcement for tampering with the emission system (assuming that you would receive a visual inspection and the inspector even knew what the were really looking at and whether or not law enforcement could tell - your probably pretty safe with it gone, just know that you may have issues down the road).

TrevorS · 10-02-2009, 08:50 PM

Good input

!

Speaking for myself (Delaware), all parts I've removed I've kept, and so if I ever have a need to restore them, I can

!

myleshouston · 10-03-2009, 09:24 PM

So glad i live in south dakota we don't have emmisions here so you can do whatever you want to your car and get away with it. they even let atv's drive on the rode. haha

PCH · 10-05-2009, 01:39 PM

Quote:

Originally Posted by awinter

By removing the carbon filter element (the part riveted in the top of the air box) you have tampered with your emissions system which is illegal (in California). When it comes time to have your car smogged, you may run into issues by not having this part. You can also be cited severely by law enforcement for tampering with the emission system (assuming that you would receive a visual inspection and the inspector even knew what the were really looking at and whether or not law enforcement could tell - your probably pretty safe with it gone, just know that you may have issues down the road).

Yeah, but chances that anyone would ever notice you removing that screen are 0.
The screen is there mainly to prevent any crankcase fumes from venting to the atmosphere after the engine has been shut off.

TrevorS · 10-05-2009, 07:23 PM

Quote:

Originally Posted by PCH

Yeah, but chances that anyone would ever notice you removing that screen are 0.
The screen is there mainly to prevent any crankcase fumes from venting to the atmosphere after the engine has been shut off.

Is that what it's for! Thanks, I really didn't know

! Seems hard to believe it's effective as a one way filter, so I'm thinking it probably is very restrictive to air flow through the box. However, the filter area is much larger than the OE snorkle cross section, so maybe it isn't so bad in the OE configuration.

snkysnake · 10-07-2009, 08:49 PM

My new TRD CAI has the same mesh filter screen on one half of the box, the TRD/K&N filter goes in the other half

TrevorS · 10-07-2009, 09:13 PM

Interesting, is that why it's CARB certified? I somehow doubt any of the competitors include that screen or equivalent filtration.

PCH · 10-07-2009, 09:45 PM

The built-in screen is only slightly resrictive. Gen1 boxes lost 2HPs on '06 models (that's when the same screen was introduced first) compared to '04-05s but that may be not just due to added filter but also because of the different ways to measure power output. I think there is some charcoal in that screen so it absorbs whatever it needs and later the motor pulls the fumes out and burns them. It's used on most of Toyota cars now.

TrevorS · 10-08-2009, 01:54 PM

Quote:

Originally Posted by PCH

The built-in screen is only slightly resrictive. Gen1 boxes lost 2HPs on '06 models (that's when the same screen was introduced first) compared to '04-05s but that may be not just due to added filter but also because of the different ways to measure power output. I think there is some charcoal in that screen so it absorbs whatever it needs and later the motor pulls the fumes out and burns them. It's used on most of Toyota cars now.

As a charcoal trap, effectiveness will depend on the proximity of carbon molecules to the charcoal, and the greater the average proximity, the greater the air flow restriction, so I wonder how effective it really is? In any case, I would expect a fair reduction in potential air velocity through it. However, given the OE snorkle is already highly restrictive, it may well have a negligable additional impact.

Thinking of the TRD CAI carbon screen -- does it have about the same flow area as the OE filter?