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'02 Legacy Outback Wagon - Wintergreen Metallic - 4EAT - Electrical grounding mod, custom intake mod
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Discussion Starter #1 (Edited)
Okay folks; first I have to give props to MudRunner for doing this first, I just copied him. So here it goes.

Materials -

1 - 2" flexible couplings (there are 2 in the first pics, but that was before I made it just like MudRunner's)
1 - 2" to 3" flexible coupling
2 - 2" PVC 45 degree street elbows
1 - 2' pc. of 2" PVC pipe
1 - 3M 2pk '00' steel wool pads
1 - 11oz spray can of Plasti-dip coating



Tools I used -

1/4" drive socket wrench
1/4"x3" socket extension
8mm 1/4" drive standard depth socket
10mm 1/4" drive standard depth socket
Hacksaw
Tapemeasure

First I removed the factory air box tubing. Then I placed the 3" side of the 2" to 3' coupling into the 3" opening in the passenger side fenderwell. This was a tight fit, but works very well at holding the coupling in place. Then I placed the 2" coupling onto the air inlet portion of the air box. This was another tight fit, but produces a good seal. Next I placed one of the 2" PVC 45 degree street elbows into each of the openings. Then I measured the 2" PVC pipe and cut it to a 10" length. (My first cut of this pipe was too short). I could have made it a 10-1/4", but hind-sight is 20/20.
Once all off the pieces were put together, I removed them from the car, taped the ends, and sprayed it with the Plasti-dip. Once everything was dry, I re-installed it all in the car, and viola', one custom intake.





Once again I would like to thank MudRunner for doing this first!

Cheers all!

Bob

PS - All of these parts, even the extra 2" coupling that I will be returning, only cost $31.43 (tax included). So definitely not a high cost mod.
 

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2003, Subaru outback H6, ll bean Ed.
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107 Posts
you should post this on the " what did you do to your 2nd gen today"! but where is the filter or did you take that off and connect it with out one?
 

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'02 Legacy Outback Wagon - Wintergreen Metallic - 4EAT - Electrical grounding mod, custom intake mod
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19 Posts
Discussion Starter #3
athomas2k8 - the filter is still in the factory location, by the throttle body. Basically all this mod did was make for a more direct air path, and no resonators. It really seems to be helping with throttle response at all RPM ranges.
 

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2003, Subaru outback H6, ll bean Ed.
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107 Posts
o ok, so where exactly is the air being taken from now? since it goes into the fender, where does that lead?
 

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'02 Legacy Outback Wagon - Wintergreen Metallic - 4EAT - Electrical grounding mod, custom intake mod
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19 Posts
Discussion Starter #5
o ok, so where exactly is the air being taken from now? since it goes into the fender, where does that lead?
The air still comes from the front of the car, but just to the left of the bumper support (if you're looking at the car straight on). There is no tube going down into the fenderwell, hence not a high enough chance of getting anything into the intake over the factory setup. Think of the fenderwell as a 'heat shroud' like you would find on a high end K&N intake system. The air coming into the intake is coming from below and in front of the engine, therefore cooler air. :29:
 

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2003, Subaru outback H6, ll bean Ed.
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107 Posts
I just did thi last night, can't really feel to much of a difference yet since the hurricane jus passed nd the raid r all messy.. But their should be no harm if using this for a long time?
 

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'02 Legacy Outback Wagon - Wintergreen Metallic - 4EAT - Electrical grounding mod, custom intake mod
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19 Posts
Discussion Starter #8
I just did thi last night, can't really feel to much of a difference yet since the hurricane jus passed nd the raid r all messy.. But their should be no harm if using this for a long time?
Post some pics. Let's see it!
 

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2003, Subaru outback H6, ll bean Ed.
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107 Posts
i just realized these were all on 2.5s, i did this on my h6.. after doing this it feel like it has a cleaner shift when changing gears
 

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2018 and 2006 Outback Wagons
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73 Posts
Has anyone noticed an increase in intake or exhaust noise with this type of mod ?

I believe they design those resonators on the factory intake to reduce intake air noise. I equate reduced intake air noise with smoother airflow. So I would think taking them out would actually work against better engine performance.
 

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Off Topic

Darksyde,

The intake looks real good!! I have aquestion that is off this topic, what is up with the red ground cables, is that an upgrade to do to these subys??

Thank You
DZ
 

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2002 Outback Wagon 2.5L Auto Weather Package
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1,971 Posts
Has anyone noticed an increase in intake or exhaust noise with this type of mod ?

I believe they design those resonators on the factory intake to reduce intake air noise. I equate reduced intake air noise with smoother airflow. So I would think taking them out would actually work against better engine performance.
Sound is produced by air moving. The faster and higher the volume of air moving, the louder the sound generally is. Turbulence is also a factor.

With that in mind, consider that air moves fastest, with more total volume, and the least turbulence in a straight line with few distortions in its path. Every extra bend and turn slows the air flow, and every little side chamber cause some sort of turbulence that dampens air flow. Points of general constriction can also cause air to 'back up', inducing a sort of pulse or resonation. In most cars, that point is the throttle body or intake duct as it reaches the air cleaner plenum, or both. This constriction is what causes a sort of 'honk' sound in some vehicles at full throttle. Its basically a sign that you are running out of enough space to pass the air the engine wants. When it only happens at full throttle and fairly high RPMs, its not a really big deal. This situation is common on most decently engineered cars for the street. (They aren't race cars after all.)

Since it does occasionally happen on some cars, or often on others due to being engineered with economy and power limitation over outright performance, manufacturers use these 'intake mufflers' to induce a turbulence which is engineered to cancel such resonant intake noise. Put that all together and you'll realize you are sacrificing some flow (and hence power) for quiet and perhaps a touch better economy.

So less noise can mean less power. You have to know why the noise is being made. The best thing about the mods shown here is that you are providing a straighter, cleaner path for the air. You might experience that wide open throttle 'intake honk', but that's not indicating a loss of power.

Besides, it sounds cool! :cool:
 

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2005 OBW 2.5i, 2010 MB R350 Diesel, 1991 Toyota MR2 | suspension & braking enthusiast
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660 Posts
Has anyone noticed an increase in intake or exhaust noise with this type of mod ?

I believe they design those resonators on the factory intake to reduce intake air noise. I equate reduced intake air noise with smoother airflow. So I would think taking them out would actually work against better engine performance.
You are correct; you will indeed hear some booming around 2200RPM with the factory resonator removed on the 4-cylinder cars.

The airbox/plenum that holds the air-filter (up till 2004 non-california spec 4-cylinder cars) is the only performance tuned portion ahead of the intake manifold/throttle body. If you remove the plenum/airfilter and replace with a cone filter, for example, the whole tuning of the intake changes and you'll have a different torque peak. But any plumbing changes ahead of the plenum will result in negligible performance changes.

On 2004 California 4-cylinder, 2005+ 4-cylinder and all 6-cylinder cars, the air filter is located in a box right behind the headlight and there is a separate plenum or "chamber" attached to the throttle body. On these cars, I think you can get some gains by replacing/modifying the air filter box behind the headlight for better flow.

The 2006+ 2.5L has an updated intake manifold that I beleive improves flow. So if you want the ultimate performance, grab one of those from a wrecked car and swap it in. It should do a lot more than swapping around the plastic bits.

You can see the two styles of intake manifolds here:
http://opposedforces.com/parts/lega...d_supply_system_turbocharger/intake_manifold/
 

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2001 Subaru outback LL bean H6
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21 Posts
Quick question, I noticed you guys have the filters in a different location than I do. On my 01 H6 the filter is by the fender, any ideas of how to mod that?
 

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2005 OBW 2.5i, 2010 MB R350 Diesel, 1991 Toyota MR2 | suspension & braking enthusiast
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660 Posts
Quick question, I noticed you guys have the filters in a different location than I do. On my 01 H6 the filter is by the fender, any ideas of how to mod that?
Yes. There are two halves to your air filter box and a resonator underneath. You can remove the resonator and plug the hole with duct tape or something. You can also remove the side of the air box closest to the headlight and fasten the filter to the remaining half with some long zip-ties or clamps (You need the filter to seal properly otherwise you'll allow dust in)

This will change the sound of the intake and potentially increase airflow - especially if you remove the headlight :)

Other than that, there isn't a whole lot you can do.
 

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2005 OBW 2.5i, 2010 MB R350 Diesel, 1991 Toyota MR2 | suspension & braking enthusiast
Joined
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660 Posts
Quick question, I noticed you guys have the filters in a different location than I do. On my 01 H6 the filter is by the fender, any ideas of how to mod that?
Yes. There are two halves to your air filter box and a resonator underneath. You can remove the resonator and plug the hole with duct tape or something. You can also remove the side of the air box closest to the headlight and fasten the filter to the remaining half with some long zip-ties or clamps (You need the filter to seal properly otherwise you'll allow dust in)

This will change the sound of the intake and potentially increase airflow - well if you remove the headlight :)

Other than that, there isn't a whole lot you can do.
 

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2003, Subaru outback H6, ll bean Ed.
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107 Posts
sooo wait, i have a 2003 h6 and i did the same mod as the 2.5s did in the picture.. but before that i had already took the old square filter out and added some tubing along with a cone filter(short ram intake)... after seeing this thread i took off that cone filter and just plugged one long strechy tube from the throttle body all the way to one of the two holes on the inside fender which i though was the resonator. is this bad since i took of the filter and now its letting dust in? but one thing i hav noticed after doing this was a smoother air flow when the car changes gears.. before with the cone filter it felt like it was bogged down sounding and the car would kinda jump forward after shifting..if you kno what i mean
 

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2003, Subaru outback H6, ll bean Ed.
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107 Posts
this is how it looked with my cone filter except i took out that black box the filter is sitting on


 
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