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Everyone loves modding their Subies. I for one can’t leave any car I have owned stock. My previous Subie, an 04 WRX, had an 18G turbo and was tuned to just over 300 hp at the wheels (on a Mustang dyno). Stage II STI’s couldn’t keep up. So to keep from spending time in jail, I bought an 07 B9 Tribeca Limited 5 passenger in gray. Being that the B9 is a family hauler, no one makes anything fun for it. I had previously made a custom intake for my wife’s 06 Legacy 2.5i followed in suit from the guys on legacygt.com forum. I figured, “Why not the B9?”

The core of the intake is an eBay special. Look for an intake made for 95-01 Imprezas that looks like this.


With the engine cover off, this is what you’ll have.


You will reuse the hose clamps, the standoff/mount and rubber standoffs for the engine cover. You will need one more additional hose clamp (3”-3 ½”). Remove the standoff/mount for the engine cover using a 10mm socket. Remove the oil vent line on the driver’s side from the intake box. Lastly, loosen the hose clamps at the throttle body and at the air filter box. You can remove the intake in one piece. This is what you’ll have.


At this point, you can remove the two rubber standoffs on the intake box. You will reuse these to remount the standoff/mount for the cover. Don’t forget to remove the other hose clamps to use later.
 

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Now to fab up the intake tube purchased off of eBay. You will need to cut off the portion at the weld line. Cut on the side of the weld that we will use for the intake. That way we will have a smooth area to put on the 90 degree hose coupler.


Make sure to clean up all the edges with a file so there is nothing sharp and pieces to flake off. I took a drill bit and reamed out the only vent line fitting left on the tube. Not to enlarge the vent line fitting, but to clean up and enlarge the hole where it is welded to on the tube. Remember, high speed and light pressure since it is aluminum. You’ll see what I am talking about when you look at it. Make sure to thoroughly clean out the inside of the intake.

Next it’s time to hook up the oil vent line at the intake. You will need about 2 feet of ½” rubber tubing to extend the oil vent line. It will eventually be trimmed to fit. At the vent line fitting on the intake I used a ½” 90 degree nylon barbed coupler that I was able to directly fit over the vent line fitting. It was a pseudo interference fit and stayed on firmly when I pressed it down into place. It was a good sealed fit, but I additionally used electrical tape that is rubber and seals to itself without adhesive (I can’t recall the name at this time and will update it when I find it). You can use traditional vinyl electric tape if you wish. Make sure the 90 degree nylon fitting will point straight aft and that the hose will not be hitting on anything when the intake is in place. To connect it to the existing vent tubing you will need a ½” straight barbed hose coupler. Go ahead and install it into the OEM side of the oil vent line. You can buy these nylon couplers at the local home improvement store. I used ones purchased from McMaster-Carr online and are bought in bulk that I already had from previous projects. As for the 90 degree one, I’m not sure if the ones bought from the local stores will fit well over the oil vent fitting on the intake. If not, you could use some of the tubing from the intake kit from eBay and a straight coupler and hose clamp. But the eBay hose is not a real snug fit on the vent line fitting.
 

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Discussion Starter #3
To get the intake installed you will need to buy a 90 degree and straight silicone coupler both 3” in diameter. You can buy them inexpensively from here: http://www.siliconeintakes.com/. Loosely hook up the intake to the throttle body and air filter box.


Next, check to see how much you will need to trim off the ½” line to make it fit well. Once everything looks like it will fit, go ahead and tighten it all up and connect the oil vent lines together. You can secure the oil vent line to something with a zip tie to keep it from moving around too much. Make sure there is some clearance between the intake manifold and aluminum intake.


Last thing to do is reinstall the standoff/mount for the engine cover. Grab the standoff/mount and the rubber standoffs removed from the air box. Loosely mount one at a time with the original bolts so you don’t drop anything. Tighten up the two bolts snuggly (they don’t need to be real tight). Check and make sure there is good clearance between the standoff/mount and intake.


Now install the engine cover and call it done.


Start it up and make sure it is idling smooth and that you don’t get a CEL. A CEL would probably indicate a leak in the intake so check all your connections. To suck in a little more air and get a little more noise you can remove the resonator under the air filter box. Also, a K&N OEM replacement air filter will flow a little more air.
 

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Looks good, thanks. Been waiting for something like this. (I can't leave my cars stock either)

I was just going to remove the resonator and drop in a k&n. I take it that the oem intake is really restrictive with the airflow? Is that why you changed it? How hard do you think it will be to just remove the resonator?

(I dont actually have my Tribeca yet, but I am getting all my mods ready before hand.)

You should post some pics for us that don't want to change the hose but just want to remove the resonator, as that should be much easier. Unless its like my mazda where I had to remove the wheels, half the fender, and even the horn.
 

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Discussion Starter #5
The air filter box/resonator is very easy to remove. Remove ram inlet (two plastic screws). Remove one nut at the front top and a bolt at the bottom. Unplug the MAF and unclip the wire bundle from the box. The whole unit pulls right out. There is a white plastic screw type thing to remove at the connection between the two. Stick a flat blade screwdriver where the tang from the resonator goes into the relief of the air box. Lift it a bit, twist the resonator and pull it out. Done. Installation reverse of removal. Just don't forget to plug back in the MAF connector.
 

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How is the throttle response? Normally it's not a good idea to remove the air plenum behind the throttle body. It's there to supply a large volume of air when you tip the throttle. We sometimes called it a torque box back in the day. When I did my custom intakes on my scoobies I would leave that in an plumb to it.
 

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Discussion Starter #8
Peaty said:
How is the throttle response? Normally it's not a good idea to remove the air plenum behind the throttle body. It's there to supply a large volume of air when you tip the throttle. We sometimes called it a torque box back in the day. When I did my custom intakes on my scoobies I would leave that in an plumb to it.
I think the throttle response is good. The problem is that I modded it before I had time to really get to know the car. At times when I pop the throttle to take off it feels very responsive. I was kind of hoping others would try the mod to see how it works for them. But I guess the Tribeca crowd is a little less adventurous than the other Subie owners. :(
 

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It looks like the maf sensor housing from my 07' 2.5i would work to replace the b9's stock one. So that I could put a cone filter adapter on the end. Then that would allow for a nice free flowing cone filter.

Does this sound like it would work? Any pros or cons to this?

Of course this is using your idea of the intake pipe from ebay and all.

Look at the pic for the 2.5i intake and tell me that it wouldn't work just like it does on the 2.5i.

http://www.cosmoracing.com/productinfo.asp?cid=226&pid=1498
 

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Discussion Starter #10
4urxtc said:
It looks like the maf sensor housing from my 07' 2.5i would work to replace the b9's stock one. So that I could put a cone filter adapter on the end. Then that would allow for a nice free flowing cone filter.

Does this sound like it would work? Any pros or cons to this?

Of course this is using your idea of the intake pipe from ebay and all.

Look at the pic for the 2.5i intake and tell me that it wouldn't work just like it does on the 2.5i.

http://www.cosmoracing.com/productinfo.asp?cid=226&pid=1498
As long as the inner diameter of the MAF sensor is the same as the B9's, you should be fine. There might be subtle dimensional differences between the Legacy and B9, but there's only one way to find out.
 

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hawker800mech said:
I think the throttle response is good. The problem is that I modded it before I had time to really get to know the car. At times when I pop the throttle to take off it feels very responsive. I was kind of hoping others would try the mod to see how it works for them. But I guess the Tribeca crowd is a little less adventurous than the other Subie owners. :(
Very true, or just have less time to invest.

As much as I would like to get more time to modding, the lack of available products can be quite discouraging. I am watching this thread with a keen eye, however.

We are ending up waiting for someone to start, and test, and then slowly follow suit.

Hawk, I dub thee Tribe Explorer. Go where no one has gone....:patriot:
 

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hawker800mech said:
I think the throttle response is good. The problem is that I modded it before I had time to really get to know the car. At times when I pop the throttle to take off it feels very responsive. I was kind of hoping others would try the mod to see how it works for them. But I guess the Tribeca crowd is a little less adventurous than the other Subie owners. :(
1st of all Thanks!!! Not sure many people like you and me own Tribeca's! The first thing I said when I was driving it off the lot was, man I hope I can find a turbo kit for this thing! No luck yet, but thinking of an Turbo EJ20 swap...... but first I think I will try your route and see where it leads. Any luck finding a cat-back or header-back exhaust system yet?
 

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Discussion Starter #13
I've had my stock intake on for a few months. I put it on to see if I can get better mpg. The power shifted to the lower rpms which gets me better mpg by about 2 mpg on avg since I don't have to tip in the throttle as much. The custom intake has a real nice sound and pulls well all the way to redline. I think the custom intake gives it enough sound without needing an exhaust. I came from a 04 WRX with a straight through exhaust...I didn't want that much sound again. I'm sure a custom turbo can be done, but may cost a bit of cash. You would, I'm sure, need a custom programable ECU to replace the stock one. Those are at least a grand. It would be pretty cool, though.
 

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i custom fabbed an intake one entire piece of aluminum 45's and 90's all welded, found online a DENSO style MAF housing (used on Mazdas and Subarus) and finished off with a beautiful Cobb cone filter :) quite beautiful, amazing tone, a bit power loss under 3000rpm, but i cannot lie, the tone is mean and the power is a bit more. next im doing the magnaflow cats, deleting the collector pipe and doing 3inch to a 3inch Y-pipe, to magnaflow mufflers, and possibly stock tips. havent found any tips that caught my eye yet. hopefully with a reflash and a fuel pump i wont need to look for a turbo. Hawker and Tskuba, as for not having many Tribeca owners like you, you have one more! haha
 
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