DIY: Drop-in Air Filter Replacement
 

This is a guide to "properly" instal a drop-in air filter. I put this together because I am seeing questions about how to instal a filter (i.e. just shove it in the box and force it closed) which will not seal the airbox and can let dirty air into your engine.

It's actually a pretty simple process.

Tools Required:
- 10mm socket wrench
- Your replacement filter

1. Start by removing the three bolts circled here. The blue circled bolts hold the front half of the airbox while the red circled bolt holds the back half. (some people might say that you don't need to remove the blue bolts, but I wanted more leverage so YMMV)
http://i.imgur.com/jbJOcuw.jpg?1

2. Once the bolts are removed you can slide the airbox back and off of the snorkel.
http://i.imgur.com/mbUigPy.jpg?1

3. Release the silver clips and the airbox should open up into two halves.
Take out the stock air filter and put the replacement into the front half of the airbox.
The air filter will have 3 rounded edges and one that sticks out. Align that tab with the airbox as shown in the photo.
http://i.imgur.com/43ljdB2.jpg?1

4. You will now need to slide the two halves of the airbox back together. I say slide because if you try to wedge the two halves back together, you're going to have a bad time.

Put this tooth...
http://i.imgur.com/RG6EdsU.jpg

...into this hole. (there are two teeth and two holes...figure it out)
http://i.imgur.com/vLoan1U.jpg

5. Now just kind of work at the two halves of the airbox until they fit together. It took me a few tries to get everything to fit correctly but you'll know when its right.

The airbox is aligned correctly because there wont be any force trying to open the box back up, you should just be able to hold it closed without any force.

6. Double check the alignment tabs on either side of the airbox, I've put example images of a bad seating and a good seating.

BAD BAD BAD
http://i.imgur.com/bEqjQHi.jpg
You can see the that one tab is pressing on the other, which makes it stick out. open the airbox up and try again.

Good Good Good
http://i.imgur.com/nhUJR4B.jpg
The tabs sit next to each other but do not touch. The airbox is rigid and does not flex or wobble when force is applied in any direction.

7. That's it, slide the airbox back around the snorkel and rebolt the airbox to the car. You have successfully installed an air filter...

Nice diy

Sent from my Galaxy Nexus using Tapatalk 2

thank god for your tutorial, I'm such an idiot with cars. This is idiot approved!!

Simple fix, but always nice to have a DIY. Thanks!

i should have read this when doing my drop in installation. i put in the filter into the second half and tried closing it, and it wouldnt close 100% and was wondering what was going on, drove it like that for a little bit and car felt strange so i switched filter around and put it into the front air box (side that is behind the front air scoop) and it fit perfectly. car also drove normal again

This was quite a bit more difficult than I thought it would be. I thought maybe I had gotten the wrong filter, it just didn't seem to be fitting.

Same here. I am just going to redo again. My car seems like having air leak because it's not fully closed?

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I'm pretty certain I got mine. It couldn't stay completely closed without pressure, but it was lined up right. The bottom of the enclosure looked a bit off though, I'll take another look at it tomorrrow.

Definitely have to remove the airbox to do it. Both parts, which means disconnecting the MAF line, which has one of those gray clips, which was also a pain.

You are right and that is what i am going to do

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There's no need to remove the MAF sensor unless you want to completely remove the airbox from the throttle body. You just have to work it a bit in order to get a good seal.

It's very hard to explain what that means but I will try...

The airbox has four things holding it closed:
2x Metal clips on the top side
2x plastic "teeth" that slot into holes on the bottom side.

The main issue is that the teeth might not be set all the way into the holes. As you can see from the photos, the tooth has two widths and the hole is in a T pattern. The risk is that you only get the tooth halfway in and only on the bottom part of the "T". You can close the airbox with the teeth half set like this, but the bottom half will be loose (if you apply pressure to the top of the airbox the bottom will wedge open a bit).

Just work to get the teeth all the way into the upper part of the "T" and everything will line up proper. Of course, that requires two hands and the air filter is not going to cooperate unless you take your time as it likes to pop out and slide around if you even look at it the wrong way.

I took out airbox and redid it. It fits tight but made sure i got in. Only took10min
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Found this after replacing my air filter with the K&N -- this was exactly how the process went for me, and for anyone who has never done air filter replacement before this is a good guide.

I came here to write a quick one up, but this is more than sufficient. Nice work OP! :happy0180:

PS: First post :burnrubber:

will be doing this soon thanks for the DIY :)

This made it really easy. Thanks for the quick easy DIY guide.

I recently drove on some dusty dirt roads behind some other vehicles (for a long time), so I wanted to pull out my air filter to be sure it wasn't caked in dirt. It was surprisingly clean and so I wanted to make sure I put it back in right. Does anyone else see the white original filter along the edges? It looks to be sealed tight and the filter does have a pretty big edge around it that appears to be intended to squish in there to seal it up. I can't see how better to get it on honestly. (it's not upside down either) If I need to tear it out again I'll do it.

Top
http://i.imgur.com/oGVYDTd.jpg

Bottom
http://i.imgur.com/nhXF1OZ.jpg

Sides
http://i.imgur.com/7QfElXD.jpg
http://i.imgur.com/rzJn1Q6.jpg

Here's a picture of the stock one for those that haven't seen it yet. Note the thick border around it.

http://i.imgur.com/A26CCo4.jpg

I'd try reseating it again if you're not 100% comfortable with it. There looks like a lot of bowing at the top. Worst case take it to the dealer and plead ignorance.

So I went back this time and took the entire thing out per the DYI above. That is basically as good as it gets, it's not designed to enclose and seal completely around the air filter perfectly, the edges of the air filter seem to be incorporated as part of the full seal or are at least too thick to fit in properly (hence the bowing).

I just did the trd filter tonight and at certain angles you can see the red putter part exposed. My last car the filter was completely closed off and for completely inside the air box. This air box seems to allow you to see the outter edges across the top and on the left side.

I'm assuming this is normal? My clamps fit really easy without any effort but I'm still kinda freaked because I can see part of the polyurethane peeking out...

IMO, this should be in the DIY Directory Link...

I've since switched to the Apexi drop-in and even it shows at the bottom on each side if I recall correctly. That's what made me realize ultimately that the borders are part of the seal design. Here I am with the Apexi, notice it's sealed the same all around (it has a black border, not white like the stock filter).

http://i.imgur.com/tJcuupC.jpg

http://i.imgur.com/Et1qaRa.jpg

http://i.imgur.com/V70JUVD.jpg

thank god someone else notices this. its inherent in the design of the box. I just think I noticed it more because my filter is red. Everyone elses is black therefore they probably never noticed it.

How has your apexie been running for you btw, any problems with it

Butt dyno is happy, it just seems a little more "full" than the stock filter though it's not a big difference of course. I settled on that for a combination of reasons. It's a dry filter so low maintenance, the price was on the low end, I could pick it up locally, and it had good results here (they test several different ones in the video series):

[ame="http://www.youtube.com/watch?v=Tzvx3ISlKus"]2013 Scion FR-S Intake: APEXi Dyno Test - YouTube[/ame]

Very nice write up
I took a look before I install my Perrin filter
When I install the filter I notice there's a few mm sticking out on all sides but I can easily push it in. Makes me wonder if other people using the Perrin filter have the same extra border.
I end up take out the whole box as precaution to make sure it seal properly before I reinstall so from the looks of it it was indeed seal properly then I just reinstall it and took it out for a spin.
For the initial 3 miles test drive on the empty highway it does feel like it pull better from 5.5k - 7.2k on all gears.

Thanks for a great write up

:respekt:You have that extra border showing also?

It's like the made doing an oil change super easy but an air filter change a little harder to just to balance it out...

A few mm on all 4 sides
Now I'm thinking of triming it tmr just to be sure it 100% sealed properly

Let me know how that goes

The way I see it no air goes through that border, it is part of the seal. So if you trim it allowing the plastic box to come closer together, hard plastic edges won't seal against each other. So I'm thinking that would make it have less of a seal.

Does it matter which way the filter goes in? I installed mine the other way around from the picture in the first post and it sealed fine. Just want to make sure that it's fine like that and I don't need to open it back up and fix it.

I just want to thank you for taking the time to make this guide. Very helpful.

I'm pretty sure it's meant to flow one way, otherwise it wouldn't have an arrow pointing, etc.

very good and detailed DIY thank you! I actually used it today when i installed my K&N filter. It took me a while to get the air box sealed properly (still have a feeling it's not aligned but that's just my OCD kicking in) but I must say, that filter works wonders! I never knew what everyone was talking about when they mentioned the "Torque Dip" until today! This filter gets rid of some of it. Also, noticeable gains, well, on the butt dyno at least! lol anyway, Thanks again

I unbolted the blue screws, the red one is hard to get to and I didn't want to screw something up. The blue screws did make the airbox loose enough to properly install the filter though.

After I installed the filter, I get this "ripping paper" type sound when I step on the throttle. IDK what I did wrong? :( Can somebody chime in to what this might be?

Thanks for this and thanks for the clarification of the excess protruding from the air box. I actually had placed it in backwards initially AND had only released the top bolt. I hated dealing with the pieces serparately, so next time I'm going to see if I can do it with just removing the top bolt and dropping it in there correctly.

Instructions were unclear. I got my **** stuck in the ceiling fan. 0/10.

Good post the air filter wont fit unless you undo these bolts glad you put all this detail in

I installed mine over the weekend and have a good fit of the filter in the airbox, but when I installed the airbox back into the snorkel there seems to be a small gap. I don't remember if it was like this before taking the airbox out of the snorkel.

That's funny, this exact question is on my mind after I reinstalled the filter assembly last night.

I installed a K&N in mine last night. When I initially reassembled everything I had a similar gap between the airbox and the snorkel, but I was able to fiddle about a bit and get it sealed properly before tightening the screws back down.