DIY/Modified Splitter for 02 WRX scoop with 04 STi TMIC

[enginerd]

OK so I picked up a used USDM STi TMIC from an '04 because it was cheap, my OE WRX IC was shot, and I could get a part that actually says STi on it. Installation into '02 WRX Wagon was OK, have some slight hose fitment issues form the slightly adjusted mounting points on the IC (STi drive by wire throttle body is ~17mm bigger). The hoses are holding for now and I am looking for some longer replacements, but I have another small issue...

I have a stock WRX scoop and air splitter, which is really just a hole in a plate with a vertical fin to separate the turbo cooler slots from the IC flow. I think I have enough sheet metal in the stock splitter piece to cut out a larger opening for the much larger STi TMIC. I have ordered the STi rubber billow seal thingy and will do some cutting and drilling this weekend to make some custom DIY modifications.

Reasoning...I didn't really want to spend ~$200+ dollars on a JDM STi splitter and scoop, and I really don't like the look of the big scoops. If my mod. plan doesn't work I will have to go this aftermarket route. I'll try to take pics and post a write-up..if I'm successful.

[enginerd]

A look at the the new STi TMIC and Billow (below) compared to the stock WRX air splitter.



The new STi billow mounetd perfectly along one edge and I measured off the areas to cut out and new holes to drill.



Cutting out the 'excess' material.



Done with modifications of the splitter.



The whole engine bay after installation of modified splitter.



A look down the scoop after installation. The DIY worked out very well for less than $40 (for the new billow) and around 1 hour for removal, modification, and reinstallation.

[enginerd]

UPDATE: Added a couple layers of weather stripping between the splitter and the scoop to make it a little more air tight.

Also replaced turbo to y-pipe hose (2" x 90 deg) and TMIC to TB hose (2.75" x 3" cut down to about 2.3" long) with some great quality and inexpensive hoses from https://www.siliconeintakes.com/

FINAL:

Used STi TMIC w/ Solid one-piece Y-pipe $200
New STi Rubber Billow Seal thingy $40
Longer Hoses $40
3/4" thick x 1/2" wide x 10' long weather stripping $5

Stuffing an STi intercooler into a WRX...priceless

[soobiewagen]

Noticed gains?

Just for my own curiosity.

[enginerd]

Well I wish I had the time and money to do a proper testing of this product with a dyno. The real problem was that my old OE WRX intercooler was simply clogged with gravel, and had oil vapor inside all of the cooling fins. It simply wasn't functioning as well as a new one would. So simply fixing that issue did make an improvement to my air flow, and adding in a one-piece solid y-pipe helps the turbo spool quicker and smoother. I know one thing for sure...it never gets hot to the touch like my old WRX IC did so I'm assuming that I'm getting better cooling and lower intake temperatures.