DIY CAI - How To - Cost ~$60

[Rdkill]

Ok, this is what I did to my 08 S, on the account that only one company makes one for this model (That I could find) and its $250...plus I wanted to keep a stock look and not flash my chrome CAI all over the place. It costs about $40 for me (didnt get a K&N, $75 or so if you go with K&N). First off, heres what you need...

1. Several feet of 2'' ABS Pipe (Home Depot) *Melting temp of around 230F...no worries as long as its not touching engine or radiator, which it doesnt in my setup.
2. (2) 90 Degree joints (Home Depot)
3. (1) 2'' to 4'' adaptor (varies with air filter selection)
4. Appropiate Glue..
5. Something to cut the pipe with.
6. White out (yes you need it...)
7. Tools (duh)
8. Air Filter (duh)

Ok here we go...first you need to pop the hood and pull out that crudy stock intake.


To do this..you need to unscrew the fusebox and take out the battery...


Now take the air filter out of the air box and remove the nuts inside it to lift it out of place. (Dont have to completely remove it) Remove the stock intake.


Now we need to locate our hole where we can get cold air, this can be found just behind the headlight and can easily be seen with the stock intake removed.


Now its time to get under your car...hopefully you dont have it lowered or you wont fit (I barely can get my head under). Once under look infront of the left wheel, there is a plastic wheel well cover, we need to get this out of the way. Luckily its flexible so it doesnt need to be completely removed. Locate the bolts shown and remove the one plastic clip. Then Pull down and to the right of the car and it should slide out enough for you to see inside.


Now you need to cut the pipe to fit...my dimensions are below, yours may be different, check to see and always cut a little longer than you think you need.


The filter is going to go like this in the car...


Check your angles, slide peices together and check the fit...if its good CAREFULLY remove the intake and use white out to mark the angles for the peices. NOTE: For me, the only way to get it in position was to insert it from UNDER the car.



Well if it looks like it fits DONT GLUE IT YET. First attach the expansion pipe as well and put the intake in place, then attach your air filter to make sure your have enough clearance to put the wheel panel back on.




Hold your breath and glue the peices together. Check the fit again and if you did it right, it should still fit. Put the fliter on, and go topside. Slide the 90* pipe into the stock air box (I had to sand the pipe a little to get a good snug fit) If it fits, mount the airbox. I also drilled a little hole in the intake tube and the airbox to put a screw through to hold it snug. Press the intake into the air box and go back under the car.

Now put the air filter on and replace the wheel guard, be sure to slide it into the "slot" on the side. Did it work?


Mount the fuse box, put the battery in and take a look...


Finally...fire it up , I noticed a slight difference in sound though not as deep as it could be due to the pipe diameter.

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Advanced
* You could route your custom CAI right from the intake hose, if you used large enough pipe, and drilled a hole for the MAF. This would require complete removal of the aair box of course.
* Feel free to make this out of metal pipe if you wish (autozone has the stuff) Just mark it and weld it yourself if you can, or take it to a shop to have it done for you.
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Hope you enjoyed this, if I left anything out, let me know.

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I am also currently doing custom under dash LED neons for a friend, if anyone is interested, I can post a tutorial for those too.
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Congrats on your new custom CAI.

[JasonA]

Nice job, and good pics. Even if you retain the stock air filter, this is a good way to get some slightly cooler air from under the car.

[JasonA]

Hey, just as a point of discussion, I checked my lower filter box and it has some holes in the bottom of it, likely to drain any water/condensation. So if your filter is upstream of that, you are ingesting unfiltered air into the engine through those holes. It's not a LOT of air to be sure, but you may want to double-check yours and seal it off.

I went and removed the air snorkel on mine tonight. Later, I may fab up an air tube like yours. I'll keep the stock Denso filter in it, but I like the idea of getting cooler air from down below.

[mikered30]

Watch out for large puddles.

[Rdkill]

No problem with water so far and I've driven it in the rain a few times. The "splash guard" does quite well in covering the filter. It can only get air from the side. Plus the water would have to go almost straight up, I'd worry more about a "mist" like when on the freeway after it rains. Inside of the pipe is perfectly clean so far though, about 800 miles on this setup.

I also noticed the holes...just a dab of silicon would fix that, although I dont think it makes too much of a difference.

[FinalGear]

+ 2 for OLD SCHOOK.....

[JasonA]

I did this today on mine. I used a 90-degree elbow at the top, a length of 2" ABS plastic pipe, then a 60-degree elbow. With the angle of my pipe, the lower 60-degree elbow puts the air "inlet" at the bottom perfectly perpendicular with the ground.

I am keeping the stock Denso filter in the box. I'm just using this to get some cooler air from the bumper area, rather than from behind the headlight as Toyota had it. I doubt I'll see any difference, but it's fun to tweak anyway (especially for less than 10 bucks)!

To the original poster, I would absolutely plug up those holes in the air box. You can pretty clearly see increased silicon in a used oil analysis just from a loose-fitting filter (from dirt and pollen getting passed), let alone holes in the air box. Considering how easy it'll be to plug 'em, I'd go ahead and do that.

Thanks again for the great idea, and the great pics.

I may play with it further to do a "ram air" thing with the fog light cover. I may see if can find an extra one from somewhere, cut a hole in it, finish it nice, and plumb my pipe to this hole.

[Rdkill]

Thanks for the replys guys, Ill plug those holes tomorrow, the ram air idea sounds cool too but I cant do it do to the fact that I have a fog light there . Post some pics if you get it working.

[JasonA]

My Lowe's store had threaded 2" ABS fittings, so I think I may install a threaded fitting on the end of my pipe as it is now. Then I can connect another part of the system later, and be able to take it back apart rather than cementing the whole thing. What I have now is cemented, and I can just BARELY snake it in there. I had to attach it to the air box with three set screws, so the whole upper half of the system (which is all I have now) is "1 piece".

I'll fool around with it some more in the coming days. I'll post some pics when I can.

[JasonA]

Okay, here's what I got.

I have a 2-3" adapter (just like you have on your filter) acting as my intake collector. From the front:



Now, from below...from the collector back, I have a short 1" section of pipe, into a broad 90-degree elbow. Then about 5-6" of pipe to the 60-degree elbow where the pipe turns toward the air filter box:



Here's where my system ended yesterday, with the lower 60-degree elbow. This view is from above:



Now...what to do about the "ram air" part? I want to find a panel from a fog light projector, like what's shown below. I don't want to simply cut a big hole in my fog light delete plug; that'll look ghetto. That projector light has a real nice finished hole in it, which would be PERFECT...without the actual projector of course. I found this pic in a for-sale ad on another Corolla forum, so I'll contact that person and see if they'd sell me a pair of just the plates, without the fog lights.

[Rdkill]

That looks pretty good, seems you get a lot more room to work with when you dont have to attach a huge air filter like I did. That fog cover is really nice too, smooth opening and would look clean on the outside.

[TrdSpeed140]

now you're gonna have to be EXTRA careful about water gettin in there

[JasonA]

Originally Posted by TrdSpeed140

now you're gonna have to be EXTRA careful about water gettin in there

I've got a "ram air" thing like that on my Dakota also. Works just fine. Water has a LONG path to take to get up into the air box to begin with...once it gets there, there are drain holes in the air box to let water out.

I've actually changed it a bit. I have the air intake collector turned about 45 degrees toward the center of the car, to pull air from the front of the radiator area, so I can put the fog light delete panel back in. So now there isn't a direct opening to rain, and puddle water can't really get to where the collector is, for all the under-body plastic cover panels there are. I may just leave it that way, but it'll depend on what I hear from the guy on the other board about the fog light panels. If I do go this route, I may cut some "slits" in the bottom of the lower 90-degree elbow parallel to the flow. Looking at it head-on, they would look like vertical cut lines in the back of the elbow. That would sieve the bulk of any water right out the back/bottom of the elbow.

[TrdSpeed140]

good thinkin'. maybe you should just go ahead and buy the fog lights as they are since they're so sexy lookin'

[JasonA]

Originally Posted by TrdSpeed140

good thinkin'. maybe you should just go ahead and buy the fog lights as they are since they're so sexy lookin'

Maybe. And they weren't all that expensive either ($150 for the pair).

Anyway, it's a cold and dry week, so this morning before I left for work I snatched the fog cover back off, turned the intake forward, and went to work. I can't really tell a difference over what I started with, which was just routing the pipe into that blank area behind the fog light area (basically, where rdkill has the filter). So I may just finish it off like that, and put the fog plate back on. I think the opening is small enough where I don't really get any "ram air" effect.

I don't know...I'll play with it some more. It's going to be bone dry all week, so I may just leave it there and see if I notice any more difference over time.