DIY Quads Air Filters / Filter Screens

[Victim]

Note: Had to break this up into two seperate posts because I had too many links.
Let's be honest here, filter socks look gay.
Nuff said.
Everyone wants open throttles. Mmm... Open throttles.

But even so, I wasn't willing to sacrifice my engine sucking up rocks for the sake of looks. My car is a daily after all, so the option of running no filters isn't cool.

Whilst searching for a replacement to gay socks, I found that Jubiride make a filter screen that you insert between the trumpet and the throttle body that block large objects from being inhaled:



But to me, ~$75 seemed a bit over-the-top for what essentially is a piece of metal mesh sandwiched between some rubber, and something that doesn't filter anything. Hence, I made my own for substantially cheaper, and which also have the added benefit of filtering, not just stopping rocks and larger objects. If you just want a screen, then just don't include the foam filter layer. What could be easier?

I originally stole this idea from Clug4AG to see how easy it could be done, it works quite well. Well enough for me to wonder why more people don't use this as an alternative to socks. I also wanted to reinterpret that guide because he uses the intake gasket as part of it, whereas my throttle set-up has the trumpets detachable and separate to the intake gasket, and I didn't feel like replacing the OEM intake gasket every time I went to replace the filter foam.

Inspiration from Club4AG:


I recommend you read through my guide before doing it, as I've given a few tips along the way which will make your life easier, and mean you don't have to trial-and-error it as I did.

Tools needed:
- Scalpel (can buy cheap ones from officeworks. Highly recommended, makes life easier)
- Pair of scissors
- Ball-point pen (any colour will do, I found that black was the easiest to work with though)
- White permanent paint marker (Officeworks)
- The two bolts that hold the trumpets onto the throttle body
- A single trumpet to use for templates

The paint marker I used, for reference:


Materials needed:
- Air filter oil (I got mine off eBay for cheap)
- Zip lock / glad bag
- A sheet of thin rubber (mine is 1mm thick, you can use whatever you want though, but to me any thicker seemed like overkill). I bought it in a meter-long strip which was more than required, but it's nice to have some spare to allow for fuck-ups. This applies to all materials you'll use (foam, metal screen).
- A sheet of foam (I didn't want anything super restrictive & dense, I got foam that you can see through when you hold it up to light. It's around 12/13mm thick. Obviously keep in mind that when you bolt down the trumpet the foam will be compacted slightly but once again use your own judgement as to what would be the best foam for your application. Don't get that yellow foam that you find in seats and cushions, you know the one I mean, it's far too dense and will restrict airflow like a motherfucker, but that's just my opinion)
- Metal mesh screen, somewhat like the consistency of fly-screen.

As a note, I found that Clarke Rubber was a one-stop-shop for the foam and rubber. They have heaps of different types of rubber and foam in all manner of thicknesses for your browsing pleasure. The metal screen I found in my local Mitre 10, but I’m sure Bunnings / another hardware store would have something similar.



The consistency of the mesh I used:


The thickness of my foam:


The Process

Step 1: Using your ball-point pen, the strip of rubber and one of your trumpets, trace an outline of the mounting surface. Be sure to include the bolt holes, the hole for the adjusting screw if applicable, and the hole for the intake. Repeat this template 9 times, as you will need 2 for each throttle + 1 extra to use to make templates using the white paint pen that you can get paint all over then throw away (saves getting paint on one of your trumpets).

TIP: Try and use a ball-point pen that you can take the flexible ink barrel / chamber out of. I found that I couldn't get the pen into the bolt holes to trace the shape because the pen was solid and wouldn't bend, but because the ink barrel is bendable it allowed me to get into the tighter holes.







Step 2: Cut one rubber template out on it's own. You'll be using this to make final cuts and measurements until you are happy enough with it's shape to replicate the cuts for the foam & metal screen pieces and to ensure it fits hellaflush. I found that when cutting out the various holes it worked best if I cut outside the line by a small amount, say 1mm, to make sure it didn't impede on airflow or bolts, as illustrated below. Use scissors to cut out the intake hole and the scalpel to cut the smaller holes.

TIP: I found the easiest way to cut the holes was to bend the template in half and make a cut in the intake hole, enough to fit the scissors through, then cutting straight to the edge, then following the circle around. For the bolt holes I found that I had to make small individual cuts with the scalpel, taking it out each time, rather than cutting it in one hit, if that makes sense.



Cut inside the line, about 1mm in:


This is what you should remove:


This is what you should be left with:


What it will probably look like first time (thus, requiring a trim):


What you should end up with, to ensure that it doesn't impede airflow:


Step 3: Using the mounting bolts, mock up the template on the trumpet to see if you've done a good job cutting it out and that all the mounting holes line up, the template doesn't interfere with any airflow through the middle, and that it sits flat. I used pencils in this photo because I couldn't be bothered going out to my car and getting the two bolts, but anything that fits through the bolt holes will do to mock it up into place. Don't eyeball it, chances are when you actually have the bolts through them, it won't be square and will impede on airflow. Best practice, yo.





Step 4: Now cut out the rest of the rubber templates. The reason I say to only cut out one first is now that you've mocked up one, you know roughly how much to cut out around the holes to make sure the rest fit flush if need be, rather than cutting them all out first, then having to go back and re-cut them all. Once this is done, separate them into four piles of two. That's your "gasket" component sorted for all four throttles, let's move onto filtering.

Rubber "gasket" components completed. (The other pair were still on the trumpet at the time this photo was taken):


Step 5: Take your white paint pen, the one throwaway rubber template, and your sheet of foam, and trace out the shape onto the foam. You will need this piece at least four times, one for each throttle. This part is a bit of a bitch because foam isn't the easiest stuff to write on. I found that it worked best if I only lightly pressed onto the foam, rather than trying to press really hard, as the foam shape will distort if you do this, and you won't get a nice clean outline. Remember that you only need to mark the overall shape of the trumpet and the bolt holes, you obviously won't need to cut a hole in the middle as you'll be leaving this in place to filter the air.

TIP: As you can see in the photo further down, I made spares. I managed to get the initial set, plus two sets of four for replacements for later on down the track, out of my cut of foam. This filter element is the only piece you should need to regularly change, much like any air filter. You don't have to make spares, but as I said above I had material left over, so figured I'd make more for when I changed the filters later on down the track whilst I was on a roll, rather than have to do it again later. But if you don't have enough foam, you will only need four initially to make a set.



Step 6: Cut out one foam piece around the outline. Only do one, for the same reasons as only cutting out one rubber piece initially, as said above. Guaranteed this will be the part where you will need to re-cut the piece, as foam is a real bitch to make it play nice. The foam pieces will look retarded and out of shape for some reason, every one I cut out did. Don't mind this for the moment.



TIP: Following the same principle as cutting outside the line for the rubber templates for the intake hole to make sure it doesn't restrict airflow, do this as well for these foam pieces, but inside the white line for this part. This is because the nibs on the white paint pens are huge and you will be left with a large amount of unsightly foam hanging over the ends if you follow the outside of the line, so you're allowing for this tolerance when cutting. This also means you won't have any nasty looking white paint on your shiny black filters.

Step 7: Mock up the shape on the trumpet. You will more than likely need to shave some off around the edges to make it sit nice and flush, with no bits overhanging over the sides. You don't have to be this pedantic, but I wanted them to look nice and hidden when they're bolted down.

TIP: Test for overhanging areas by putting the foam on a table, then placing the trumpet on top (as illustrated in the photo) then pushing it down, mimicking what it will be like when the trumpet is actually bolted down. This will make the foam squash outwards. Trim if needed.





Step 8: Cut out the holes that the bolts will go through. This part is a bit annoying because it's not easy to make a nice cut through the foam as it's not solid, but I found that the easiest way was to use scissors, and almost hollow out the hole. I made lots of small cuts, burrowing into the foam, then working the hole larger. Don't go too large though, as the holes are close to the edge. It's hard to describe, but I hope you get the general idea as to what I mean. The one consolation prize is that because the foam will expand as need be when you put the bolt's through, it doesn't have to be a great hole, just enough to fit the bolt through.

Not a great picture, but you can kinda see where the holes are:


Step 9: Test-fit the holes to see if the bolts will pass through. I once again used pencils, but don't be a lazy cunt like me. Use the bolts, as it's a more accurate representation. (The pencils are the same thickness as the bolts though. Jus' sayin) You may need to work the holes slightly bigger if it's difficult to get the pencil / bolt through the hole. Don't force it too much, as it'll more than likely tear. Repeat until you're happy with the holes.



Step 10: Mock up the pieces you've currently got for one throttle, IE grab the trumpet, two pieces of rubber and one filter. Run the bolt / pencils through all the holes to make sure they're all fitting together flush (as illustrated) and that everything is lining up with everything else. You, in theory, could stop here, but I don't trust the foam not to get sucked into the motor because it's too easy to tear in my opinion, hence the metal screen.

[Victim]

CONTINUED

Step 11: Cut out the rest of the filters from the foam sheet. You will now know how much to cut off in terms of the white line and how thick the nib is on the paint pen you used, you can see in the picture how much my rough tolerance was (bottom left) although you're more than likely still going to need to shave the sides anyway. Cut all the bolt holes whilst you're at it, and follow steps 7 through 10 to ensure each filter piece has good-sized bolt holes, doesn't have any overhanging parts, and sits flush with the rubber & the trumpet. Awesome, that's your filters done, plus spares if you had enough foam. Making progress.



Step 12: Time to make the metal screen component, which holds the foam in place to stop it from being sucked into the motor, and provides stronger support to stop rocks getting sucked in. Whilst foam will do this, it doesn't hurt to be cautious. That was my thinking anyway. Take your white paint pen, your throwaway rubber template, and mark out the screens, once again only marking out the overall shape and the bolt holes, as you're leaving the middle in place. You will need two per throttle, so 8 in total. You won't need spares as the screen won't get replaced, but you can if you want. I didn't.



Step 13: Cut out one screen using scissors, once again cutting inside the white line to allow for the tolerance of the fat nib on the paint pen. Don't cut off too much though, as you don't want the screen to be too small and you can always cut more off later. Scissors should do the cutting adequately, if they don't feel free to use tin snips, but I found them to be too big to get around the tight corners and they bent the screen.



Step 14: Mock up the shape of the screen on the trumpet, using the marks you made for the bolt holes as a guide. You will probably need to shave some of the sides off like you did with the foam.

What they will look like first time, before you trim them down:


Once you've trimmed them down:


Step 15: Cut the holes for the bolts into the screen. Honestly, don't bother trying to make a circle cut for the bolts, it won't work. Because there is so little holding the individual pieces of metal together for the screen, they start coming apart and flaking off, and will get sucked into the motor, and small metal pieces getting sucked into a motor isn't cool. Cut straight from the outside edge to the outside of the bolt marking, as illustrated. Remove any small pieces of metal near the edges that aren't held in place and look like they will come off, use your judgement as to what looks like it's not secure and what isn't.

What I mean by not cutting holes for the bolts, and cutting from the side in.






Step 16: In much the same fashion as step 10, mock up your progress with all the pieces you've made for one throttle so far, so two rubber pieces, one piece of foam, and one screen. Once again, everything should be flush and not overhang the edge of the trumpet.







This is the consistency of the foam I used:


Step 17: Cut out the remaining filter screens and their respective bolt holes, and check every throttle filter assembly individually to check for flushness etc. Take another screen and test it, to complete the assembly of one throttle's filters, as shown. (you can see the two separate screens either side of the foam)







Step 18: Viola! You've made your filter screens. Congratulations. You should have a pile that looks like this (for one throttle, obviously multiplied for all four of the throttles) consisting of two rubber gaskets, two metal screens and a filter piece of foam:





Step 19: Take four of the foam filters that you plan to use for this application (leave the spares alone) and pour some filter oil over one (you can buy it off eBay), and put it wet into a glad zip-lock bag. Moosh the oil into the filter inside the bag to get a nice even coverage over it (the bag stops it getting all over you) then take it out and evaluate how sodden it is. You obviously don't want it saturated, but you don't want it too dry. If it's too wet take some of the oil off with paper towel, if it's too dry add more and get to mooshing. Do one at a time to ensure consistency.

Step 20: Yew dawg, you've made your filter screens. DIY like a motherfucker. Jubiride can blow me. This is the point where you are permitted to revel in the fact that ladies refer to you as the "4AG pimp", and how true that fact is. Contemplate also the fact that you probably should have gone to uni to get an engineering degree.



Hope this guide has helped someone!
Death to socks. DIY this bitch and you'll have the best of both worlds: a filtered intake system, without the hassle of gay red socks hanging off the side of your motor.

Peace.
- Alex
"LDYKLR" AE71.

[Sam-Q]

this is quite interesting and I think you did a good job in making it however there are a few things that concern me-

would that foam stop fine dust particles? as this is what really kills your engine

if that foam flameable? or how about petrol/heat resistant?

would this cause a partial reversion wave which would reduce you intake resonance?

[Celica RA45]

you will find that it will kill engine respose .check it on a dyno as they will loose power every where
thats why air boxes are a great idea

[blair]

kill engine response more or less than propper sock filters?

[takai]

More, much more.

Yet another example of people doing things for looks .... oh wait, thats just ricing it up isnt it

[Sam-Q]

I think this guy had good intentions here so I don't think that's the case. I also think while I don't agree with the concept his hand skills seem to be ok

[roadsailing]

the road to doing silly things is paved with good intentions.

OP, have you driven it with like this yet?

a while back a mate had put a 4AGE in his sprinkler and had to move it somewhere, had no air filter so he cable tied an old ramflo foam filter over the throttle body inlet, it made the car very quiet and extremely slow.

OP i can see what you are trying to do but this isnt the way to do it.

[lolwat]

pen15 lost 15 kw im pretty sure it was from running stocks, and if your really going to be that precise about responce and still filtering air, you would have an plenium on it

good write up, as said before (sorry if you did answer) have you driven it with the filters in?

[takai]

Nope im pretty sure he just wanted the looks: