The "Catch Can" Explained - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Apex Motorsports · 08-22-2011, 08:36 PM

The "Catch Can" Explained

Added Aug 22, 2011, Under: Engine,General Automotive

Modern engines feature a variety of emission control devices and systems to reduce the toxic gases released into the atmosphere. One of these is called the Positive Crankcase Ventilation (PCV) system. During the combustion process a small amount of gases leak or “blow-by” the piston rings and create a positive pressure in the crankcase. The PCV system vents these gases along with oil mist from the crankcase and routes it back into the intake manifold so it can be burned off. The problem is, over time the excess oil vapor collects along the inside of the intake tract and forms a “gunk”. This can lead to a variety of issues including carbon build up, retarded timing, detonation, and power loss.

An oil-air separator is an aftermarket device that will condense and collect the oil vapor before it has a chance to reach the intake system. As the gases and oil vapor enter the can they typically pass through a screening mechanism that gives the oil vapor something to adhere to. As the droplets form they drop harmlessly into the bottom of the reservoir so that they can later be drained. The other gases are allowed to pass through so that they can be burned of as intended. These devices are often referred to as “catch cans”, though that term is truly more accurate when describing a fluid overflow tank designed to just capture leaking or overflowing fluids.

When it comes to selecting a catch can you will get what you pay for. Cheap catch cans (less than $100) are plentiful but they are often little more than an empty can with two ports. These will capture a small amount of oil but the vast majority passes straight through. Be sure that the can is designed to be opened so that it can be periodically drained and cleaned.

BullF-16 · 08-22-2011, 09:28 PM

I just put this same can on my car. Elite engineering? In only a week and a hundred miles i checked inside and saw the inside of the collector reservoir had a coating of oil all over the inside and just a drop or so of oil at the bottom.

LS7 427 · 08-22-2011, 10:36 PM

Excellent explanation Chase.

Also, I might add, an absolute must for any roots style forced induction application as the residuals enter back into the intake prior to the super charger.

jcmG8 · 08-22-2011, 10:40 PM

For those who dare to learn the details -> HERE

BigRed585Lbs · 08-23-2011, 06:45 AM

EXCELLENT! Should be a "sticky" if it isn't all ready.

Thanks to jcmG8!

08-22-2011, 08:36 PM	#1
Apex Motorsports Drives: 2000 Camaro SS Join Date: Feb 2010 Location: Louisville, Ky. Posts: 25,179	The "Catch Can" Explained The "Catch Can" Explained Added Aug 22, 2011, Under: Engine,General Automotive Modern engines feature a variety of emission control devices and systems to reduce the toxic gases released into the atmosphere. One of these is called the Positive Crankcase Ventilation (PCV) system. During the combustion process a small amount of gases leak or “blow-by” the piston rings and create a positive pressure in the crankcase. The PCV system vents these gases along with oil mist from the crankcase and routes it back into the intake manifold so it can be burned off. The problem is, over time the excess oil vapor collects along the inside of the intake tract and forms a “gunk”. This can lead to a variety of issues including carbon build up, retarded timing, detonation, and power loss. An oil-air separator is an aftermarket device that will condense and collect the oil vapor before it has a chance to reach the intake system. As the gases and oil vapor enter the can they typically pass through a screening mechanism that gives the oil vapor something to adhere to. As the droplets form they drop harmlessly into the bottom of the reservoir so that they can later be drained. The other gases are allowed to pass through so that they can be burned of as intended. These devices are often referred to as “catch cans”, though that term is truly more accurate when describing a fluid overflow tank designed to just capture leaking or overflowing fluids. When it comes to selecting a catch can you will get what you pay for. Cheap catch cans (less than $100) are plentiful but they are often little more than an empty can with two ports. These will capture a small amount of oil but the vast majority passes straight through. Be sure that the can is designed to be opened so that it can be periodically drained and cleaned.

08-22-2011, 10:36 PM	#3
LS7 427 10.11 @ 136.32 Drives: Black & Yellow 2SS/RS LPE LS7 427 Join Date: Mar 2010 Location: Redcliff, Alberta Posts: 957 View My Garage	Excellent explanation Chase. Also, I might add, an absolute must for any roots style forced induction application as the residuals enter back into the intake prior to the super charger. __________________ My Build Journal Built, Tuned and Maintained By........

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08-22-2011, 09:28 PM	#2
BullF-16 USAF retired! Thank God! Drives: 2011 1SS, 1LT red,1LT/RS SGM 98Z28 Join Date: Jul 2011 Location: North Texas Posts: 2,799	I just put this same can on my car. Elite engineering? In only a week and a hundred miles i checked inside and saw the inside of the collector reservoir had a coating of oil all over the inside and just a drop or so of oil at the bottom.

08-22-2011, 10:40 PM	#4
jcmG8 Drives: G8GT Join Date: Jan 2011 Location: Vermont Posts: 90	For those who dare to learn the details -> HERE

08-23-2011, 06:45 AM	#5
BigRed585Lbs Drives: Sierra and Tahoe Join Date: Jul 2010 Location: By Marion, MS Posts: 1,324 View My Garage	EXCELLENT! Should be a "sticky" if it isn't all ready. Thanks to jcmG8!