DIY Custom Intake (Hybrid CAI)

[99gtlimited]

So I've finally completed my intake system, after many different set-ups, i've come up with one i'm finally happy with and happy to share with all of you.

Time From Concept To Installed Product: ~ 3 hours

So here's the basic idea: (preface)

I used the stock airbox (1) with a K&N drop-in filter in conjunction with piping from a Weapon R SRI (2) (although the ebay intakes would work just fine). I used a 2.75" coupler (3) to link the TB and intake piping, and a 3" coupler (4) to link the piping with the MAF. You have to drill a hole in the larger coupler to insert a 90 degree elbow with a 3/4" line that runs to the IAC. The other two bungs on the intake should go to the PCV and the Valve covers (i used a T joint (5) to link the valve cover lines and run them to the intake piping)

This is what it looked like with the the Hybrid intake set-up and a snorkus removed with the factory fender plug installed.
https://sl-i.net/FORUM/images/imported/2008/11/IMG_3889-1.jpg

WARNING: DO THIS AT YOUR OWN RISK!!

0.If you haven't already removed the snorkus, you need to do it before you can make this intake. (you need to remove the fender liner to get to it properly and remove it)

With that out of the way you should see this: a lot of room behind the foglight
https://sl-i.net/FORUM/images/imported/2008/11/IMG_3886-1.jpg

1. With the car safely off the ground and the front right wheel off (passenger side) you can see the inside of your airbox through the hole where the snorkus attached to the airbox.

https://sl-i.net/FORUM/images/imported/2008/11/IMG_3892-1.jpg

With your cutting tool of choice, cut the top part of the snorkus off at the elbow where it connects to the airbox (we're gonna use this connection)
https://sl-i.net/FORUM/images/imported/2008/11/IMG_3900-1.jpg

2. Now that you've cut the end off, you need to file the edges so there are no major burrs or sharp points. We're gonna connect this tube to a piece of 3" diameter PVC piping that will be aimed down behind the foglight to draw air much colder than that drawn in from the engine bay. I used about 10" of the PVC. I bought a 2' piece of 3" OD PVC for ~$3 and a 3" bracket to hold it for ~$2, so all in all the cold air part of this mod only cost me $5!

{test fitting the elbow
https://sl-i.net/FORUM/images/imported/2008/11/IMG_3888-1.jpg

elbow joint and PVC piping
https://sl-i.net/FORUM/images/imported/2008/11/IMG_3893-1.jpg

I put some mesh over the end of the tube to prevent it from sucking up anything that may make it's way back there.
https://sl-i.net/FORUM/images/imported/2008/11/IMG_3894-1.jpg

3. Next part is modding the bracket to support the tubing. I used a 3" round bracket to hold the tube (#2) and connected it to a hard steel piece i broke off the end of the round bracket for lateral support (#1) and hung it with plumbers tape for vertical support and shock absorbtion.

the round bracket shown with the two separate pieces used
https://sl-i.net/FORUM/images/imported/2008/11/IMG_3895-1.jpg

4. Once you've got it all cut to size you have to fit the plumbers tape on the round bracket to help support the tube in the fender well.

https://sl-i.net/FORUM/images/imported/2008/11/IMG_3897-1.jpg

I used a small nut and bolt to fix the plumbers tape to a hole between the airbox and the fender plug hole.
https://sl-i.net/FORUM/images/imported/2008/11/IMG_3898-1.jpg

5. Now you can install your fender plug and get back underneath the car. I attached the more rigid bracket to a part of the frame near the bumper using a nut on the bolt of the round bracket and a nut and bolt into the frame. (#1)

https://sl-i.net/FORUM/images/imported/2008/11/IMG_3902-1.jpg

6.Heres what you should see now: a pipe ready to get air from that empty space behind the foglight

https://sl-i.net/FORUM/images/imported/2008/11/IMG_3899-1.jpg

7. Now you put the fender liners back in (if you so choose, the airflow to the filter will be better without the liner but for those of us who are concerned about puddles i would put it back in. (you can always take it back out come summer time!)

https://sl-i.net/FORUM/images/imported/2008/11/IMG_3901-1.jpg

8. Sit back and marvel at your accomplishment! you just make one of the more worthless parts ever on a subaru into something that makes your car unique!

[Huffer]

Excellent writeup. I did a similar thing with some white PVC piping a few years back to my Impreza.

[99gtlimited]

yeah, i've had this idea for a while, glad to finally get it to work out. I'll post my initial feelings about it once i get some driving done.

[xXGTBspecXx]

im doing the same thing with my car. well except im using flex tube to get a demonic whistle noise.(like when you blow into a flexy straw)

[99gtlimited]

i really didn't want that noise

[99gtlimited]

Initial Thoughts: Wow! the torque from 1500-3000rpm has improved quite a bit, along with throttle response. The car also makes a somewhat loud "growl" as is creeps up the RPM's (mostly above 3K). I do have a few planned additions to this mod that will help get rid of any vibration caused by the piping or bracing. I plan on getting some rubber grommets to use as sound deadening washers so the piping will still be firmly held in place but will not create any rattle as engine speed increases. I'll pose pics of that update when i get it done.

Other than that, I am extremely please with this $5 mod and i can really tell the difference in how much more my motor likes cold(er) air.

This mod is definetely worth it even to those with full stock intake systems, simply for intake charge temp being lowered. No numbers to support it, but i'm just going off common sense and feel of the car. (maybe someone with a scanguage can try this out and see if there is much difference with intake air temp)

[99gtlimited]

currently working on a new prototype to help reduce the vibration in the fender well. Luckily i have a second snorkus to cut up! I'll post pics when i'm done showing the improvements made to help "rattle proof" this intake.

I'm still in love with the way this intake seems to make my car pull better, it's just driving me nuts with it rattling when i'm cruising at low speed and RPM ( 25-40mph in 3rd and 4th gear (1800-2500 rpm)

The new design will include the factory mount used on the upper part of the snorkus in conjunction with a slightly modified version of the lower bracket.

[99gtlimited]

UPDATE: here is a pic of the new tube i fabricated, notice it includes the top mounting bolt from the factory snorkus.

https://sl-i.net/FORUM/images/imported/2008/12/IMG_3924-1.jpg

I plan to shorten this as the 10" length of PVC piping seems a bit too long as it likes to rattle and make noise in the fender well. I'm thinking of making it about 4-6" to keep the cold air aspect and minimizing the possibility that this intake will keep rattling. This thing is awesome, still very happy with my $5 addition to my intake, it really makes a difference! I'll add one more update with a pic of the final product installed in the car. Hope someone else is adventurous enough to try this out.

[TheAngryPidgeon]

i really didn't want that noise

Wow. I just rofl'd for a good 3 minutes.

[abest521]

and duct tape works ok and doesnt fall off when it gets wet?

[99gtlimited]

just make sure you don't use crap duct tape and you're fine. Most good tape won't degrade with small amounts of heat or water. The tape isn't really holding too much up either, just the screen on the end of the tube, there's glue holding the two pieces together, and the tape just helps it seal fully. I wouldn't suggest using this without the fender liner if there is a chance it will see a puddle, so the water thing should be a non-issue.

[abest521]

ok cool thnx. gunna do this real soon

[Huffer]

You could also use JB weld and then paint the pipe to help seal it.

Or if you get real fancy you can plastic weld.

[Nightkast1111]

Installed today, followed the directions step by step ( was a big help ) works great can really feel it pick up, thanks for a great DIY instructions, will post pics

[99gtlimited]

awesome.. do eeeeeeeeet!!!

[GTDrifter]

what you can also do is get the older L model intakes (the ones without silencers) and after the sensor just some intercooler piping through the fender into a cone filter

[httrdd]

Cool man I have a Wepon-R intake on mine now that is craving more cold air. From dead start it accelerates slow, but from a 2-5mph roll it will chirp tires. Could be a fuel thing too.

[95USsubaru]

im doing this tomorrow!

[d1giPhux]

Anyone know where to get the 3" coupler tubing? Only pieces I can find at auto places are like 3" diameter x 2.5" length.. i need something more like 3-4" length. Anyone have any clue where to get these for cheap?

[95USsubaru]

ace, home depot, places like that OR you can make your own muhahahahahahah!!!!!

[d1giPhux]

how could I go about making my own? not really sure where to get silicone tubing and such. I might have to do that.. because I need a piece thats like 3.5"-4" long, and the 3" interior diameter.

[99gtlimited]

For the big coupler, I got mine at a plumbing store, Pretty sure home depot will have something like that. it's originally made to fit PVC pipes together and came with 2 hose clamps already on it.

Silicone tubing is easy to find on ebay, just make sure you get the right diameter (10mm or 3/8'' ID), and don't buy too much, shouldn't need more than 5 or 6 feet really.

The combination of this intake with my new exhaust sounds freaking awesome!

[chris_2.5gt]

anybody know of any material that can be used to make the intake tubing? I was thinking of making it out of pvc piping and I was curious if that would hold up to the heat in the engine bay ok?

[99gtlimited]

I wouldn't use PVC in the engine bay to be honest, at least not on the engine itself. PVC contains chlorine, which makes it fire-retardant, but could also do damage to your engine if it heated up and off gassed into the intake system. Generally I'd stay away from plastic in areas where it's gonna touch, or be near to the engine.


I would stick to metal. I don't think it's worth trying to fabricate yourself, I would just get one of the eBay intakes and modify it to fit properly, much less of a hassle and won't cost much (if any) more than making your own.

[d1giPhux]

Nice.. I'll have to check the plumbing store.. I'm just not really sure what diameter I'm going to need for the following:

Throttle Body > Intake

Intake > Filter box

I'm assuming 3" silicone tubing / plumbing tubing will work.. is that 3" interior diameter, or outside diameter?

[99gtlimited]

3" ID from piping to MAF, I used 1 2.75" ID coupler for the throttle body to piping connection (got it on eBay).

[d1giPhux]

Cool.. thanks man. I just wanna get it right before I go out somewhere and blow some money on expensive rubber fittings. Damn things are like $10 bux a piece no doubt.. I gotta check home despot.. we'll see if they have any. Did you look in the PVC section.. or plumbing section? What were they near?

[99gtlimited]

i didn't get mine there, but I'm pretty sure I've seen them in the plumbing section. Just ask a worker to help you find a 3" ID rubber coupler that's ~4" long. I'm sure they'll have it for under $10. Since the intake piping isn't 3", you'll need to tighten that side down more extra, or do what I did and add an extra coupler inside to provide a good seal without deforming the 3" coupler too severly.

[d1giPhux]

We'll I'm using non-stock intake piping anyways.. which is 3".. so that should work.. hopefully. What is the ID of the stock intake tubing.. 2.75 like the throttle body? Technically it would be nice to find a step up piece.. like 2.75" > 3" ID tube.

[99gtlimited]

yeah I have a 2.75" on the TB.

a step would be best, or you can shim a 3" to fit i guess.

[d1giPhux]

yup.. so went by home depot, and advance auto.. no such luck.

Home depot has the perfect STYLE of tube.. but they only sell them in 2" and 3".. not ID.

Basically they are made to fit a 2" or 3" pipe..

The 3" one has an ID of 3.5", and the 2" has an ID of 2.5".. sucks. So i basically need a 2.5" one.. which they don't sell.

So yeah.. back on the search. Any other types of places i could find? Sucks i don't just need like a 2" length section.. or else all the auto stores pretty much have them.. dammit!

[99gtlimited]

too bad...

check out ebay seller : siliconeintakes
that's where i got my TB coupler and 10mm silicone tubing, wide selection of silicone couplers and tubing for reasonable prices.

[d1giPhux]

Nice.. which type do you need? The 10mm?.. and what is the TB coupler spec one? 2.75 > 3" ID?

edit..

see.. i need something like this:

2.75" ID x 3" Length
3" ID Straight Pipe 4" Length.

[B's Legacy Wagon]

If your looking for some piping just dawned on me why not try a muffler/midas shop they might have metal pipes you could use. they do so much exhausts and maybe they got a pipe bender to get the custom curves you need not to mention it might be nice and shiny.

[99gtlimited]

Nice.. which type do you need? The 10mm?.. and what is the TB coupler spec one? 2.75 > 3" ID?

edit..

see.. i need something like this:

2.75" ID x 3" Length
3" ID Straight Pipe 4" Length.

did you ever find a coupler? i may be able to find one and ship it to you if it really comes to that...

[95USsubaru]

If your looking for some piping just dawned on me why not try a muffler/midas shop they might have metal pipes you could use. they do so much exhausts and maybe they got a pipe bender to get the custom curves you need not to mention it might be nice and shiny.


+1 but i donno how shiny it would be haha.

[TGX4776]

how wet does it get behind the fog? Not very i'd imagine? Thinking about placing the filter down there behind the fog light.

[hanzz]

so im new to the scubi thing..i picked up a legacy OB as my first car and it needs a little more juice...so i was thinking of doing an intake but im on a budget...i've scanned the forums and have seen mention of an ebay intake but can't seem to find anything besides basic silicone tubing...can anyone show a link of the intake? also...what was the intended function of the snorkus?

[TGX4776]

http://www.cosmoracing.com/productlist.asp?cid=150

direct fit no modification

[hanzz]

sweet...thanks!