Home > How-to > How To: NRG Catch Can in a 2005 Subaru STi

How To: NRG Catch Can in a 2005 Subaru STi

A catch can is a small container, that collects oil blown out of the PCV valve or valve cover intake hose (blow-by). The idea is to keep the oil out of the intake, which helps keep the intercooler running at maximum efficiency. This is because there is less oil vapor condensing on the inside of the intercooler. It is necessary to periodically empty the catch can to prevent it from overflowing. Some cans provide a drain for this purpose.

Catch can install and extra supplies used:
5′ PCV hose – Auto Zone
(x1) 3/4″ hose clamp – Home Depot
(x2) #14 x 1/2″ self drilling zinc hex head screws – Home Depot

  1. Optional. Remove intercooler and flush with paint thinner (or gasoline if you are rich). Proceed until liquid is clean (or to your liking).
    I had a some oil inside my intercooler after 20,000 miles of driving.
  2. Bend included bracket at straight end. You may need to test fit the catch can with the bracket screwed on to see how much bending is needed.
  3. Mark holes to be drilled on passenger side strut tower. Use pointed center punch and hammer in center of mark to prevent the drill bit from dancing around when drilling. Use a 13/64″ drill bit to make two holes.
  4. Insert the #14 screw into each hole and start screwing it in to start the threading of the hole. Make sure that the screws do not touch your front strut and springs. You may need to shorten the screw.
  5. Assemble catch can. I flipped the top so the hose barbs are toward the front of the car. I used the larger of the included hose barbs. Use teflon tape on any threads.
  6. Mount the catch can. Reinstall the intercooler if you removed it.
  7. Remove angled OEM hose from where it connects to the intake and bottom hard line of the intercooler. Connect PCV hose to nipple where OEM hose was. Cut hose to desired length to catch can.
  8. Connect rest of PCV hose to intake nipple. Secure with hose clamp. Cut to desired length.
  9. Secure with zip ties. You are all done!


Try inserting a green scouring pad inside to create turbulence so that the oil vapor condenses into liquid form inside the can.

June 2, 2007

I cleaned my catch can after about 9,000 miles and this is what I found inside.

August 31, 2010

The witness tube on the side became dark and brittle. It eventually cracked. I ended up just plugging the holes with two bolts and teflon tape. There was some sludge at the bottom of the can. It was about 3/4″ high.

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