SKU: 12273579771

AOS-R KIT, 2015+ SUBARU WRX, INCLUDES 20-0255

Sale price$199.32 Regular price$221.47
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Ships within 48 hours · Estimated delivery Aug 15 - Aug 20

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Description

AOS-R KIT, 2015+ SUBARU WRX, INCLUDES 20-0255This kit is compatible with the following vehicles that use the FA20F engine (left hand drive models only): 2015+ Subaru WRX 14 18 Subaru Forester XT High powered modified Subaru engines tend to generate excessive blow by oil and gasses. In these cases, an ordinary small catch can may quickly fill with oil and not be adequate. Like the Radium Engineering Subaru Dual Catch Can Kit, the AOS (Air Oil Separator) kit is responsible for keeping blow by oil

This kit is compatible with the following vehicles that use the FA20F engine (left-hand drive models only):

2015+ Subaru WRX
14-18 Subaru Forester XT

High-powered modified Subaru engines tend to generate excessive blow-by oil and gasses. In these cases, an ordinary small catch can may quickly fill with oil and not be adequate. Like the Radium Engineering Subaru Dual Catch Can Kit, the AOS (Air Oil Separator) kit is responsible for keeping blow-by oil and other pollutants out of the intake pipe, manifold, turbocharger, and intercooler during all engine loads. The main difference is that an AOS system returns what is collected back into the oil pan so there is no servicing required. The built-in heater keeps water from condensing in the AOS. And because water is more dense than oil, there is an integrated water trap found around the bottom perimeter of the can. This prevents water from descending into the oil pan if ever present. Furthermore, because the water is trapped against the heater, it will eventually boil and evaporate out of the system.

Same theories apply for this application. However, the direct-injected Subaru FA20F engine in particular has an inherent problem since there are no port injectors to clean the backside of the intake valves.

The AOS is constructed of CNC machined sections that screw together and are sealed with O-rings. The AOS can be completely disassembled for cleaning or servicing.

Benefits
-Effectively raises the fuel octane and increases engine performance with cleaner inlet air
-Prevents oil buildup in the intake or intercooler system walls, throttle body, intake manifold, etc.
-Lowers hydrocarbon emissions

2015+ Subaru WRX Installation
The Radium Engineering AOS kit installs on the LH side of the engine bay, near the brake master cylinder. The outlet (side port) of the AOS is plumbed back to the turbo inlet pipe, creating a completely sealed system.

The AOS mounts to the Radium Brake Master Cylinder Brace. This brace is REQUIRED for installation.

The PCV valve is replaced by a custom machined straight-through adapter fitting, shown below. Oil collected in the AOS drains out the bottom fitting and back into the engine block through this fitting.
Kit Contents
-Machined aluminum Radium Engineering Air/Oil Separator
-Specially designed mounting bracket
-All necessary SAE J30R7 rated PCV/Emissions hose
-Coolant hoses and fittings
-PCV delete fitting
-All necessary aluminum fittings and hose-ends
-Stainless steel mounting hardware
-20-0255 Master Cylinder Brace (20-0258-00 only)

Measurements
AOS Height: 6.94" (top of dipstick to bottom of AOS)
AOS Diameter: 3.45" Round
AOS Capacity: 20.3 oz (600mL)

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 12273579771

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Verified Purchase
Amazon Customer
Natrona Heights, US
★★★★★ 5
Just right for a small dog
Pattern Name: Half Ears, Size: 25 Count (Pack of 1)
Perfect for my 9 lb mini schnauzer. It's her #1 favorite treat. Keeps her busy for a long time (a few hours). Great quality. Bag lasts a long time. Have purchased multiple times.
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Reviewed in the United States on May 28, 2026
K
Verified Purchase
Karla Browner
Boise, US
★★★★★ 5
Great product and value for the money
Pattern Name: Half Ears, Size: 4 Pound (Pack of 1)
Dog loves these. I only feed her natural food and treats. These are very healthy. She's a strong healthy 2 year old puppy. Will be buying again soon. It is a great product for the money. They are chewed up in minutes because she loves them. They do have a bit of an odor but it's not overbearing.
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Reviewed in the United States on April 2, 2026
K
Verified Purchase
Kristina
Massapequa, US
★★★★★ 5
A great natural treat option, my dog approves
Pattern Name: Full Ears, Size: 8 Count, Pattern Name: Full Ears, Size: 8 Count
Ingredients: Natural pig ears 👍, they smell smoky (my dog loves it, I don’t mind it), most of the time they are a decent size. My dog is half American bully and a heavy chewer so these are a great option for him. The quality is always good, and the bags I get are always fresh. These are a good treat for him when I have to sneak out for a bit or when I am leaving for work in the morning. I have purchased these several times. I also appreciate the eco friendly bag :)
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Reviewed in the United States on February 23, 2026
T
Verified Purchase
Tannika Jones
Louisville, US
★★★★★ 4
Dog Treats
Pattern Name: Full Ears, Size: 8 Count
The pit bull and shiba inu love them.
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Reviewed in the United States on March 4, 2026
F
Verified Purchase
Freestorm
Dallas, US
★★★★★ 5
Great Natural Chew Dogs Love, but Can Be a Bit Messy
Pattern Name: Half Ears, Size: 25 Count (Pack of 1)
These pig ears are a big hit with dogs and keep them busy for a good while. They’re made from a single ingredient, which is a nice plus if you’re looking for something more natural. They help with chewing and can support dental health by reducing plaque while your dog works on them. That said, they can be a little greasy and have a smell, which is pretty normal for pig ears. Also, they may not last as long for heavy chewers. Overall, a tasty and natural treat most dogs will love, just expect a little mess.
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Reviewed in the United States on April 12, 2026

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