It is finally time for us to release our air oil separator kit for the FRS/BRZ. Below is some information regarding the kit and options, please feel free to ask any questions.
We are approximately 2 weeks away from having our first production run ready for purchase.
Our air oil separator design began 5 years ago, before Velox Motorsports even existed. It has been an area of study I have personally worked on for this timeframe and it has gone through 5 design revisions and 2 complete redesigns. Various versions have been on our shop car for over 15k miles, FT-86 SpeedFactory’s Time Attack build, and a local high horsepower build as well. We have finally consistently captured ALL oil entering the AOS and the outlet tubes are bone dry consistently as well.
Assembled unit
Coalescent filters installed
Sonic cleaned stainless mesh, nestled in its final resting place in the AOS
Coolant passage port uncovered
Coolant banjo bolts installed.
Production raw units
3D printed prototype
CAD photos
Installed photos
Overall Goals of the Air Oil Separator
-Ensure no oil/oil vapor makes its way out of the unit.
-Allow an optional drain-back system back into the engine for service free function.
-Allow the use of coolant to heat the air oil separator up to engine bay temps to reduce condensation build up.
-Have a system that can be installed without a tune and in a variety of formats.
How do we ensure no oil/oil vapor exit the unit?
-We use (4) coalescent filters, on both inlet and outlet
-Coalescent filters are designed specifically for removing oil/oil vapor from air.
-These coalescent filters can flow 57 SCFM while filtering particles down to 5 micron.
-We have found that oil vapor, which engines produce at times, is 3 microns, so further filtering is required.
-The unit has internal baffles which causes more of the oil to separate out of the airflow.
-The unit then has stainless steel mesh to further filter out any remaining oil vapor.
Optional Drain Back System
-By using our drain back system, the AOS can be used for years of service free life. No need to drain, open it up, or do anything but drive the car!
-This is optional, only those that want this function can purchase this add-on. The AOS works as a typical drain style unit out of the box.
Drain system, including 1-way check valve that threads into our rear cam block off plate.
Installed on car from the bottom.
Optional Coolant Heater
-As hot air/oil/water enter a cold aluminum unit, condensation forms on the walls. This causes the nasty slurry/foaming sludge some catch cans experience.
-With our simple to add coolant kit, you can run engine coolant through the back side of the can, heating it up to the engine’s temperature, greatly reducing this phenomenon.
-This is a larger issue in cold climates, not so much an issue in hotter climates.
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Back side, showing coolant passage
Components, not shown is the coolant line that will be supplied as well.
System Install
-By utilizing the OEM PCV valve, one can install it without a need for a tune or anything other than a plug and play install.
-By using the supplied ½” barb adapters, you can run both outlets to a vacuum source of your choice (exhaust scavenge or intake tube) to pull a slight vacuum in the crankcase.
-It is also able to be used as a venting to atmosphere unit; but, the whole idea with this unit is to pull a slight vacuum on your crankcase while ensuring no oil leaves the AOS itself.
Other neat features
-The bottom fitting is M16x1.5. This allows a Subaru Fumoto drain valve to be installed if one does not wish to automatically drain it back to the engine or use the supplied -6AN drain.
-(3) of the (4) fittings on the AOS are mil-spec o-ring bosses to ensure leak free seal.
-Hardware throughout is stainless steel
-Coalescent filters are replaceable, though we haven’t needed to change them to date or anticipate a need to change them.
-AOS is sealed with O-Rings throughout and pressure tested during assembly.
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Mil-spec ORB feature
Development
-Initial Design
Very first design, this was after ~1-1.5k miles of street driving NA.
Revised first design
This was our complete redesign unit. We found that during hard driving, extremely small amounts of oil would make its way past the two coalescent filters. Significantly more oil would be trapped in the AOS itself but we wanted no oil at all making its way out of the can. You can see the baffles we added in the photo below to help solve this. We also added a stainless mesh at the bottom of the can as well.
Won't dumping oil back in, be bad for the engine?
According to Black-Stone, everything looks good.
Oil Used: Amsoil 0w-30
Oil Cooler Used: OEM Forester
Life of Oil: This was the oil I put into the car when I put the turbo kit on, so it has been in the car for about 12 months straight and 7000 miles.
-Primarily it has ran ethanol, with a few half tanks of 91 octane.
-20-30 dyno pulls at north of 300whp.
-Half-mile racing event where it went 137MPH a dozen times.
-Typically ran at 10PSI which puts me at low 300whp.
-AOS hooked up the whole time, with auto-drain back kit installed as well.
Pretty happy with the results, I see no reason to be worried about running ethanol and the drain back valve with an AOS setup.
Thanks,
Eric