This is something I've been wanting to do ever since I first removed the IC and had a look at how small, restrictive and convoluted the OEM Y really is. Kartboy (www.kartboy.com) (Tom) was nice enough to give me a WRX Silicon IC Y that he had laying around the shop collecting dust. I thought I'd give it a try. Other than having to push the hose on a little further in on spot the install is pretty simple. I can't say what brand the hose is, I assume it's a Samco but there's no lettering on it so I cant' be sure. However, it was from a WRX IC so any silicone Y that fits that will work I should think. To find a good selection of have a look here:

http://www.kastleskorner.com

To do the mod you first have to remove the IC. Have a look at this link to see how to do that:

http://www.scoobymods.com/forums/showthread.php?s=&postid=7909#post7909

Be super careful and try not to touch the IC's fins at all. No matter how careful I am I always manage to bend a few :( . With some time and a toothpick you can get them back into shape (sort of)

Once the IC is off remove the existing hose. That can be tricky. Undo the hose clamps and wiggle up and down while pulling one of the ends off the pipe. I found it easier to get the shorter one off first then the longer side. Be careful to not hit the fins when you are doing this. It takes a little work but it will come off.

Next have a look at the pics below. You can see that one of the ends has to be pushed on slightly past the bump in the fitting. This makes it so the end that hooks up to the turbo lines up properly. Re-installing the IC is the same as in the link above with the added fun of having to hold the turbo ends hose clamp in place while making it tight. This can be a challenge as the spot is not easy to get at. To make this a little easier, have the screw to the clamp on the back side (as per the pic below). That way you can get a screwdriver or nut driver on it easier. A word about tightening the hose clamps. Don't go crazy tight, you will cut into the hose material if you do. Nice and snug is good enough. After I drive around I'll post some impressions of the mod.

I happened to have a red Samco Throttle body to IC hose. I installed it mostly because it looks good. I'm sure that's all it does :) As far as the Recirc hose, I haven't found a Si one that will fit but I'm not worried as I think that would only look good and not effect performance either.

Peaty 3/27/04

OEM IC and Y

3

4

Under side looks like this

Hook up by the turbo, note the how the clamp is positioned

Done

For the heck of it I took a pic to show what it looks like inside the IC. Pretty cool

Andrew M. asked:

I've always been curious about this mod.. what does it do?


The current "Y" has pretty small in ID, even smaller than the one on the WRX (I have the OEM WRX Y too) and it's not smooth inside at all. In fact it's very bumpy in spots sort of like an accordion. I need to take a pic of the pipe w/o the foam on it to illustrate this. This makes the flow into the IC pretty turbulent and slower rather than laminar. A smoother larger opening will get more air into the motor quicker. I've seen claims of an HP increase of 5-8 BHP depending on who's doing the selling. I take things like that with a grain of salt. I'm sure it does something for HP but I'm not sure how much. It should keep the intake temps a little cooler since the velocity will increase some. Also the OEM plastic pipe can be problematic over time. The plastic as it ages will get brittle, they have been known to crack and leak over time. It's max temp is around 135°C whereas Silicone hoses are good to around 220°C. So it's also a preventative maintenance thing too. They can handle more boost pressure too.

This is what the OEM WRX Y looks like. It's very similar to the Forester XT's. The XT's has some foam wrapped around it and it's ID is a little smaller. It's far from smooth looking inside though.