View Full Version : Catch Can Contents Summer vs Winter

08-02-11, 12:50 PM
I am about to change my can setup to a dual catch can so I can tap the fresh and the foul air lines.

These engines are a heck of alot cleaner than the Hemi 6.1ltr.

Below are pictures of 1,000 miles of collection in the winter vs summer.
I tapped only the valley port (foul air) line

Winter average temps were 25 degrees F
Summer average temp was 80 degrees

winter with condensation

summer with less/no condensation


08-02-11, 01:22 PM
I am not up-to-speed with my knowledge of how catch cans work and where they are located; but, can I assume that, since I don't have a catch can, my engine is ingesting that oily crap in your pictures?

08-02-11, 01:28 PM
The short answer is yes.

Better explanation:

An oil catch can is used in turbo applications, or high-performance race applications where excessive blow-by (leakage past the piston rings) of air and fuel vapor occurs. This creates a positive pressure in the crankcase. Engine manufactures have placed a valve on the engine block which releases this pressure. This valve is known as a PCV (Positive Crankcase Ventilation) valve. During engine operation, blow-by gases, as well as oil mist from the rotating components of the engine, pass through the PCV valve and are routed back into the intake for the engine to burn off. However, some of the oil mist and other products settle along the engine intake and over time form a "gunk." The oil catch can collects the oil mist and condenses the fuel vapors while allowing "cleaner" gases to be passed back into the intake. Typically the blow-by gasses are passed through a wire mesh, which give the vapor droplets something to adhere to. Since the oil catch cans condense the vapor portion of the gasses, they will need to be drained periodically of all the oil, fuel and other contaminants.

08-02-11, 01:30 PM
thanks for the pic cb. i had the same question as lftw8s. when my tuner pulled my sc..he pointed out that our sc take on a lot of oil. does this catch the same oil that goes in the sc?

08-02-11, 01:36 PM
Not sure Hlantin.... Maybe someone can answer.

08-02-11, 02:47 PM
It's all the same oil since we only have the one reservoir; the oil pan. Depending upon where turbos are mounted, they might need an additional pump and lines, but it all goes back to the same oil pan eventually.

08-02-11, 04:13 PM
I think I will remove the can during the winter.