Plastic Secondary Air Filter

[binary]

I searched around but haven't found this question asked/answered.When I was checking my air filter and just getting familiar with bits under the hood, I noticed there is a secondary plastic mesh between the MAF and the paper intake filter. It's attached the the filter box and is about the same size LxW as the filter.What is this oddity?

[ragingfish]

We're not positive, but I think the group agreed it has something to do with smoothing out rough air flow to help increase performance and stuff...

[binary]

That's an interesting idea. I've read that some emission systems are putting charcoal filters on the intake side... it just seems to be a plastic mesh though, kind of silly.Very much like the intake silencer on my 87 Mustang GT's air box... one of the first things to get yanked.

[binary]

I finally found out what this is...It's a hydrocarbon trap. When the engine is shut off - all the emissions that normally would get sucked into the combustion chamber - escape into the air box and the atmosphere.With this trap - the ultra secret stuff in the mesh absorbs the hydrocarbons and then release it back into the air stream when the engine starts.So there you have it. Another restrictive emissions add-on.

[zionzr2]

would this piece be easily removed/replaced as one would see fit???

[mcgusto82]

a bunch of us recently discussed this and decided test was in order. we all took it off and went on to see what develops of the mileage. so far some have reported gains. i've felt a slight increase of performance. i'm still on my first tank of gas without it. no report from me on mileage. search a forum name "what is this?"we post there.

[binary]

Quote, originally posted by mcgusto82 »a bunch of us recently discussed this and decided test was in order. we all took it off and went on to see what develops of the mileage. so far some have reported gains. i've felt a slight increase of performance. i'm still on my first tank of gas without it. no report from me on mileage. search a forum name "what is this?"we post there.Gotchya - thanks! I may have been there... can't remember - nor does a search bring up any results. I've looked around - but I'm missing it. Post a url to the thread if you get a chance.Removing it off my airbox required drilling out some plastic plugs that were melted "mushroom head" style to secure the mesh filter in. Took about ten seconds.I'm on my 2nd tank of gas w/o it - so far I'm above my average MPG by 8/10ths of a mile/gallon... but I've been driving interstate which tends to lower my overall MPG - so I'm looking for a higher MPG number with this next tank.On a side note - I notice a louder rattlebuzz from the intake at about 2900 rpm to about 3200 rpm... nothing obnoxious - but it is there. If I hover at 3k rpm, you'd swear I had a fartcan muffler... It goes away at higher rpm and isn't noticable if I'm WOT to high RPMs.

[zionzr2]

is this the thing you were talking about?

[Digger]

that is what I cut out the grid on.

[binary]

Nope, but I had one of those too.I'll take a shot of it and post it here, it's currently in the bottom of my toolbox.

[grass]

If the picture posted isn't what you're talking about, then what is it?funny.. I just put a K&N filter in today and was thinking of asking this same question.

[jasonvibe]

if you are talking about a "screen". It is simply to keep the mice out in case they take up home in you intake system.

[binary]

Quote, originally posted by jasonvibe »if you are talking about a "screen". It is simply to keep the mice out in case they take up home in you intake system.Heh, that's a good one. It's a hydrocarbon filter. Most cars coming out in '05 are having these installed. It absorbs exhaust gases that would normally leak out the intake system after the engine is shut off.It looks like it would have a significant impact on air flow, but so far with it removed I haven't seen any improvement. Most likely - it's not the most restrictive part of my intake system.

[merckx56]

I'm guessing GTs don't have this piece. I just removed the snake of an intake tube from my car. I looked in the airbox for what is pictured and didn't have that exact thing. There was a markedly different piece in there that popped right out.Without the two, it "feels" like there is a bit more low end. I'm sure I'm psyching myself up to think this...It's definitely got a growl to it now though.

[binary]

Like I said before, it's something new on '05 vehicles. Its a mesh filter, that occupies the entire box. I bet most every vehicle has one of these, I'm guessing. Brand new mustangs, F150 trucks, and I've seen them on the Impalas.Here's a photo of my wife's intake - mine is already removed. She also has a white plastic horn that most likely smooths out the air flow. Notice the [HC] painted on the top... HydroCarbon filter equiped.I agree though - after removing the mesh filter, plastic horn, and moving some of the intake track around - I hear much more intake noise. It's not bad - but it is louder than the wife's.

Attached files

[merckx56]

The white plastic thing definitely has something to do with smoothing the airflow into the intake. I just went and did some tests without it and the car seemed to stumble a bit on the 1/2 shift when jumping back in the throttle. I'm putting it back in...

[Digger]

My 05 does not have that.

[djb383]

Both of my '05s had them. Took both out of mine and left them in my wifes. The (removed) Dyno says mine runs better.

[jasonvibe]

darn,,,,one more filter to change...