well i have been wanting to make one for a long time, so this afternoon i got off my lazy rear and made one. I always had a feeling that the 04-05 WRX scoop brought in plenty of air, it just needed to be directed in the right way and onto a proper intercooler. Already have the Spearco TMIC so I was set.
First i got some galvanized thin steel ducting. Aluminum would've been nice, but i couldn't find what i wanted. This was free
Got a few tools. Metal bender, point-punch, tin snips, and not pictured is also a sawzall with metal cutting blade, pop rivet gun, drill, bits, etc.
Then i traced and cut out the base piece. Mocked it up to the scoop to get the right fitment to drill the holes.
Then i purchased some all-weather stripping for garage doors (rubber and vinyl construction). Cut some curved pieces to fit up in the scoop to direct the air onto the scoop. I also cut some flanges to attach the weather stripping. I pop riveted it all together, and mocked it up again to be sure of fitment. Found that i need a few more pop rivets in a few places.
Heres how well the final product seals onto the TMIC.
You might notice i did NOT cut a hole for air to get to the turbo charger. I also wound up making a secondary heat shield to place around the first one, and honestly i don't think a tiny bit of air coming in from the scoop is going to do much to cool off a turbo beneath two heat shields.
Also without this hole in the splitter, the scoop will not loose pressure through that hole, forcing more of it through the TMIC (this is just an educated guess. I could be wrong)
If your wanting to make your own heres some tips.
1. Take your time to make sure all the holes line up. A drill press works nicely for making the holes.
2. Be careful! I cut myself at least 3 times with that stuff. Not bad, but it can be pretty sharp.
3. Seal between the scoop and the splitter as well. This will help keep a higher pressure above the TMIC. Which should force more air through it.
Also just to see how it worked, i just got back from a couple hard WOT runs and placed my hand on the scoop. It was nice and cool to the touch, but more importantly its nice and cool all over, not just in a spot or two like the stock splitter used to make it. and its 83 and blaring sun outside.
Ideally, in the future, I will use AutoCAD3D to design one that truly has optimal airflow. And make it look a little prettier. This is kinda rough, but it gets the job done quite well. Aftermarket splitters are another option, but im not gonna pay 100+$ for something that doesn't even make use of my entire intercooler. Now all 18"x6" of the TMIC gets used! woot!