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2002 Subaru Outback Limited - 2.5 L Boxer H4 - 5 Speed Manual
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Discussion Starter · #1 ·
Hi guys. I keep hearing that the Outback came stock with a CAI. Is this true? Does my 2002 Outback Limited come with one too? Could somebody explain to me exactly, then, what a CAI is and how it works in my OBW? Thanks!
 

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2002 Outback Wagon 2.5L Auto Weather Package
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A 'cold air intake' means you are drawing your engine's intake air from somewhere that is outside of the hot engine bay. The stock ducting on the H4 in the 2000-2004 Outback goes up to a spot just above the radiator core just behind the grille. That helps deliver cooler air, and cooler air is denser, and can make more power and keep engine operating temperatures cooler. How much cooler? Honestly, without a pretty prime induction system well into 'clean air', not all that much. Its better than nothing though. The stock intake ducting gets the air from a good place, but has a lot of excess mass in the form of the funny chambers attached between where the main 'horn' (the part that looks like a vacuum nozzle) and the air filter box. These are to make the intake quieter, but cause a slight dampening of airflow and are more mass which can absorb and induce heat into the intake. If you want to try to get a little more power, and don't mind or even like a little intake 'honk', you can use a couple of methods to eliminate those chambers.
 

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2002 Subaru Outback Limited - 2.5 L Boxer H4 - 5 Speed Manual
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Discussion Starter · #3 ·
A 'cold air intake' means you are drawing your engine's intake air from somewhere that is outside of the hot engine bay. The stock ducting on the H4 in the 2000-2004 Outback goes up to a spot just above the radiator core just behind the grille. That helps deliver cooler air, and cooler air is denser, and can make more power and keep engine operating temperatures cooler. How much cooler? Honestly, without a pretty prime induction system well into 'clean air', not all that much. Its better than nothing though. The stock intake ducting gets the air from a good place, but has a lot of excess mass in the form of the funny chambers attached between where the main 'horn' (the part that looks like a vacuum nozzle) and the air filter box. These are to make the intake quieter, but cause a slight dampening of airflow and are more mass which can absorb and induce heat into the intake. If you want to try to get a little more power, and don't mind or even like a little intake 'honk', you can use a couple of methods to eliminate those chambers.
Thanks for the explanation! So, technically it is a cold air intake? Also - I do like a louder intake, haha! I'd love to know how to do this
 

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2000 Outback limited
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Those chambers also act as water dumps. Since the intake is right there in the front of the car is is easy to get water in the intake during crossings.
 

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2000 Outback limited
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Do you mean river crossings like off roading?
Yes. I guess heavy rains and large puddles as well.

For a summer I lived in a very rural area of California working for th eforest service. One the main road, there were a couple of fords. It crossed river at a very wide and shallow spot. The ford was paved concret, and it was the "main highway". Always thought that was cool and odd.
 

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2002 Subaru Outback Limited - 2.5 L Boxer H4 - 5 Speed Manual
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Discussion Starter · #7 ·
Very cool. So, I shouldn't remove these chambers then? I don't really go into any wet areas with this Subie but I guess you never know. I would like to make that intake louder, though
 

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Meh.
I has wagons.
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2002 Outback Wagon 2.5L Auto Weather Package
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Those chambers do not normally have drains, and they aren't for capturing water. They are just for dampening intake 'honk'. There's no risk in removing them really, especially if you just take care to seal up the openings when you're done. Of course, if you do something like the thread above suggests, you will actually lose the 'factory' cold air. The design in that thread is fed from the fender, which isn't 'hot', but isn't pointed directly into the airflow like the factory setup is.

Consider the designs pictured in this post from the thread above.
 

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Meh.
I has wagons.
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Bah. Meant to have that in my previous post as well.

Edit time!
 

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Meh.
I has wagons.
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12,372 Posts
Bah. Meant to have that in my previous post as well.

Edit time!
 

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2002 Subaru Outback Limited - 2.5 L Boxer H4 - 5 Speed Manual
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Discussion Starter · #13 ·
I made mine a few months ago, but just got around to painting it today.

Exactly what I am looking to do dude! Do you have a write up posted?
 

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Looks like the same basic parts as the fender exit idea, but without the 2"-3" coupler and a second 2" coupler to connect to the stock 'snorkel'. That looks like a great way to go, and glad to see it works as well as I thought it might. Now I guess I'm safe to go buy parts and do one myself.
 

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01 VDC, 05 R Sedan, 06 BAJA EJ257
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Here is an easy solution you can try before buying a lot of plumbing. This way you can determine if you notice a difference, besides the suction noise.

Simply jack up the car, remove the inner fender liner, disconnect and remove the silencer leaving the air tube, Filter box for 3.0, in place at the fender opening, reinstall the liner and start the car. This will eliminate 5 turns the air would normally make as well as allow for a cooler air mass from the fender area only as the ram is heated by thermal energy emitting from the radiator and you will not be relying on it for flow anyway. The tube will still get heat from the engine raising the air temperature, but not as high as the air heats up after passing over the ram. The less resistance the air encounters the better. Just eliminating the turns is an improvement in air flow and the speed/ease the intake can pull it in. You will hear a difference, maybe feel it on acceleration. If it comes out the way you like, then get the plumbing and spend the time assembling it. Can't hurt.
 

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Discussion Starter · #16 ·
I'm not sure I understand man? There is nothing connected to my fender from the air tube. I removed the entire air intake up to the air filter without ever getting into the fender. Are we talking about the same gen?
 

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2001 Outback 2.5 with 5 Speed
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Exactly what I am looking to do dude! Do you have a write up posted?
No write up, but like someone else said, I basically used the idea behind that fender intake, but omitted the 2" to 3" flexible coupling as it wasn't needed. then I just turned the 2nd 45* PVC elbow towards the stock front piece, and used the extra 2" coupler to connect it. It took a few times to get the angles lined up right, but it works well. Its crazy how much louder it is from like 2k to 3/4k.


http://www.subaruoutback.org/forums...rmance/38195-02-outback-wagon-intake-mod.html
 

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01 VDC, 05 R Sedan, 06 BAJA EJ257
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My bad. Your resonator is in the tube. On some designs, the air resonator is mounted in the passenger fender area.

Installing an aftermarket inlet will allow for faster air flow, not much, due to the inside of the tube being smooth instead of acordian which allows for a slight ripple in flow.
 

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Discussion Starter · #19 ·
My bad. Your resonator is in the tube. On some designs, the air resonator is mounted in the passenger fender area.

Installing an aftermarket inlet will allow for faster air flow, not much, due to the inside of the tube being smooth instead of acordian which allows for a slight ripple in flow.
It's all good dude! Thanks for the help, I'll look into doing something
 

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I was actually looking at and thinking about the rubber 'accordion' boot on the stock intake ducting. It occurred to me that's really there because it allows flexibility for when the engine shifts on its mounts under torque load. I don't know if the folks that have done the mods have had any issues with their ducts rubbing or coming loose as a result of this engine motion, but I was thinking that stock boot might fit nicely right in the middle of where the PVC run is in the aforementioned mods. I might try this once I get the bits to make my intake mod.
 
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