Cincy
05-01-2009, 01:41 PM
BY l88m22vette
Ok, so I think I've read about enough "what is a catch can?" threads/posts, and I figured it was time for one specific source of information about what a catch can does and how to install one on your 1.8T.
What a catch can does:
-- A catch can is a container which "blow-by" from the engine passes through. Blow-by is properly known as crankcase ventilation, and is pressurized air from inside the engine that is a by-product of boost. Turbo engines are not perfectly sealed and so a tiny amount of boost gets into the "other" engine spaces, such the crank area or within the valve cover. This pressure needs to be vented and the vented air carries oil particles, moisture, and other stuff you do not want in your engine; you send the air through a catch can in order to separate the oil/moisture/particulate from the actual intake air.
-- Catch cans separate the oil/moisture/particulate from the air by forcing the heavier-than-air materials to condense and collect in can rather than go into your intake. VW/Audi used a PCV valve (check valve, aka hockeypuck) to deal with the blow-by, but this is not the best solution. A catch can replaces this and the PCV system entirely; the connections come from the as-mentioned areas (block breather, valve cover breather). A catch can can either connect back to the TIP or you can simply use a filter with it (venting); I argue that putting it back into the intake is more responsible, and vented catch cans are known to smell bad because of the emissions being vented.
Diagram (based on my type of catch can):
http://i162.photobucket.com/albums/t279/l88m22vette/Catchcandiagram.jpg
DIY
I mounted my catch can to the battery box and ran hose to a steel elbow on one catch can inlet from the block breather; the other barbed inlet barb connects to my valve cover breather port. Many others use AN fittings, quick-connects, etc. but it ultimately comes down to how much you want to spend.
Basic installation:
1. Remove the intake manifold (search or buy a Bentley) so you can get to the block breather elbow.
2. Remove the hose but leave the elbow in the block breather adapter
3. Remove the black kinked hose/PCV valve assembly attached to the valve cover
4. Run a hose from the block breather elbow to one catch can inlet and run hose from the valve cover port to the other.
5. Connect the catch can vent to the TIP (if using an intake set-up) or put a filter on the catch can and use a vac plug on the TIP.
--> You will need to figure out draining, where to mount the can, and connection hardware.
Catch can where-to
http://i162.photobucket.com/albums/t279/l88m22vette/Catchcanwhere-to.jpg
Catch can I used and based diagram on (bought on eBay, fully aluminum, already tapped and came with a filter):
http://i162.photobucket.com/albums/t279/l88m22vette/DSCF0645.jpg
Ok, so I think I've read about enough "what is a catch can?" threads/posts, and I figured it was time for one specific source of information about what a catch can does and how to install one on your 1.8T.
What a catch can does:
-- A catch can is a container which "blow-by" from the engine passes through. Blow-by is properly known as crankcase ventilation, and is pressurized air from inside the engine that is a by-product of boost. Turbo engines are not perfectly sealed and so a tiny amount of boost gets into the "other" engine spaces, such the crank area or within the valve cover. This pressure needs to be vented and the vented air carries oil particles, moisture, and other stuff you do not want in your engine; you send the air through a catch can in order to separate the oil/moisture/particulate from the actual intake air.
-- Catch cans separate the oil/moisture/particulate from the air by forcing the heavier-than-air materials to condense and collect in can rather than go into your intake. VW/Audi used a PCV valve (check valve, aka hockeypuck) to deal with the blow-by, but this is not the best solution. A catch can replaces this and the PCV system entirely; the connections come from the as-mentioned areas (block breather, valve cover breather). A catch can can either connect back to the TIP or you can simply use a filter with it (venting); I argue that putting it back into the intake is more responsible, and vented catch cans are known to smell bad because of the emissions being vented.
Diagram (based on my type of catch can):
http://i162.photobucket.com/albums/t279/l88m22vette/Catchcandiagram.jpg
DIY
I mounted my catch can to the battery box and ran hose to a steel elbow on one catch can inlet from the block breather; the other barbed inlet barb connects to my valve cover breather port. Many others use AN fittings, quick-connects, etc. but it ultimately comes down to how much you want to spend.
Basic installation:
1. Remove the intake manifold (search or buy a Bentley) so you can get to the block breather elbow.
2. Remove the hose but leave the elbow in the block breather adapter
3. Remove the black kinked hose/PCV valve assembly attached to the valve cover
4. Run a hose from the block breather elbow to one catch can inlet and run hose from the valve cover port to the other.
5. Connect the catch can vent to the TIP (if using an intake set-up) or put a filter on the catch can and use a vac plug on the TIP.
--> You will need to figure out draining, where to mount the can, and connection hardware.
Catch can where-to
http://i162.photobucket.com/albums/t279/l88m22vette/Catchcanwhere-to.jpg
Catch can I used and based diagram on (bought on eBay, fully aluminum, already tapped and came with a filter):
http://i162.photobucket.com/albums/t279/l88m22vette/DSCF0645.jpg