The Original Air/Oil Separator

The Original Air/Oil Separator

Closed-Loop Maintenance-Free Protects your engine from pre-detonation and oil loss The Crawford Performance Air/Oil Separator (AOS) routes oil back to where it's supposed to be.  Forced-Induction (Turbo) motors, especially the horizontally-opposed motors used by Subaru, typically burn and consume oil especially during higher RPMs.  This was overtly apparent at the track where Quirt Crawford began to ponder how to remedy this potentially costly and damaging issue.  Tested and proven with multiple race teams and street applications, Crawford released the first ever Air/Oil Separator in 2006 creating a new industry in the automotive world.  Early prototypes were effective except in icy winter climates where condensation formed inside the device.  Later versions compensated for cold climates by equalizing the temperatures between the AOS and the engine block.  Crawford AOSs are closed-loop and maintenance-free unlike the old-school catch cans that are still in use. HOW DOES IT WORK? In the stock engine configuration, the crankcase is vented to the intake system in three different places.  Each of these vents have a baffle system built within the motor to minimize the transfer of oil to the intake, but oil still makes its way into the combustion chambers especially during periods of high performance and pressure.  When the oil enters the combustion chambers, it effectively lowers the octane of the fuel, which leads to pre-detonation.  Continued oil consumption will reduce the volume of oil in your engine enough to raise the operating temperature.  This will cause the oil to break down more quickly thus reducing its lubrication effectiveness. Our Air/Oil Separator effectively removes the oil from the air coming out of the engine’s ventilation system via a two stage process: - The first step in the process is a large volumetric swirl pot that uses centrifugal force to remove the oil from the air.  The air is then passed through a second chamber (see second step below), and extracted through the top of the AOS.  Gravity then sends the remaining oil down the walls of the swirl pot and collects in the bottom of the AOS.  At this point the separated oil sitting on the bottom of the AOS is returned to a baffled chamber in the center of the engine block. - The second step involves a second chamber located within the first chamber.  As the separated air moves up inside the AOS, it must enter the second chamber before it can vent out the top of the AOS.  The function of the secondary chamber is to remove any residual oil that may have made its way up the swirl pot.  The secondary chamber also has a drain to return any separated oil back to the engine. Our Version 2 AOS incorporates the coolant line that runs from the turbo to the engine that is re-routed through the AOS.  This effectively equalizes the temperature between the AOS and the engine to effectively minimize condensation which can occur within any AOS.  Any vaporized water leaving the motor makes its way through the AOS in vapor form, rather than condensing back into a liquid.  The Version 3 AOS for BRZ and FR-S motors and 2008-present EJ motors takes advantage of ambient engine heat while it is mounted on the block as opposed to open spaces around the edges of the engine compartment.  This V3 is simpler and quicker to install and uses fewer extra parts. See FAQ for even more information. **CLICK HERE FOR INSTALL INSTRUCTIONS**

The Original Air/Oil Separator

The Original Air/Oil Separator

Closed-Loop Maintenance-Free Protects your engine from pre-detonation and oil loss The Crawford Performance Air/Oil Separator (AOS) routes oil back to where it's supposed to be.  Forced-Induction (Turbo) motors, especially the horizontally-opposed motors used by Subaru, typically burn and consume oil especially during higher RPMs.  This was overtly apparent at the track where Quirt Crawford began to ponder how to remedy this potentially costly and damaging issue.  Tested and proven with multiple race teams and street applications, Crawford released the first ever Air/Oil Separator in 2006 creating a new industry in the automotive world.  Early prototypes were effective except in icy winter climates where condensation formed inside the device.  Later versions compensated for cold climates by equalizing the temperatures between the AOS and the engine block.  Crawford AOSs are closed-loop and maintenance-free unlike the old-school catch cans that are still in use. HOW DOES IT WORK? In the stock engine configuration, the crankcase is vented to the intake system in three different places.  Each of these vents have a baffle system built within the motor to minimize the transfer of oil to the intake, but oil still makes its way into the combustion chambers especially during periods of high performance and pressure.  When the oil enters the combustion chambers, it effectively lowers the octane of the fuel, which leads to pre-detonation.  Continued oil consumption will reduce the volume of oil in your engine enough to raise the operating temperature.  This will cause the oil to break down more quickly thus reducing its lubrication effectiveness. Our Air/Oil Separator effectively removes the oil from the air coming out of the engine’s ventilation system via a two stage process: - The first step in the process is a large volumetric swirl pot that uses centrifugal force to remove the oil from the air.  The air is then passed through a second chamber (see second step below), and extracted through the top of the AOS.  Gravity then sends the remaining oil down the walls of the swirl pot and collects in the bottom of the AOS.  At this point the separated oil sitting on the bottom of the AOS is returned to a baffled chamber in the center of the engine block. - The second step involves a second chamber located within the first chamber.  As the separated air moves up inside the AOS, it must enter the second chamber before it can vent out the top of the AOS.  The function of the secondary chamber is to remove any residual oil that may have made its way up the swirl pot.  The secondary chamber also has a drain to return any separated oil back to the engine. Our Version 2 AOS incorporates the coolant line that runs from the turbo to the engine that is re-routed through the AOS.  This effectively equalizes the temperature between the AOS and the engine to effectively minimize condensation which can occur within any AOS.  Any vaporized water leaving the motor makes its way through the AOS in vapor form, rather than condensing back into a liquid.  The Version 3 AOS for BRZ and FR-S motors and 2008-present EJ motors takes advantage of ambient engine heat while it is mounted on the block as opposed to open spaces around the edges of the engine compartment.  This V3 is simpler and quicker to install and uses fewer extra parts. See FAQ for even more information. **CLICK HERE FOR INSTALL INSTRUCTIONS**