Will the COBB Tuning Air/Oil Separator for VA Subaru fit a WRX STI?

No. COBB confirms the Air/Oil Separator for VA Subaru WRX models only, covering 2015 to 2021 USDM sedans with the manual gearbox or the CVT. It is built around the three crankcase vent ports of the FA engine, and the WRX STI from those years is not on the confirmed application list.

Is this separator legal to run in California?

Yes. COBB lists it as legal for sale and use on emissions-controlled vehicles in all 50 states when installed according to the application guide, because it carries California Air Resources Board Executive Order numbers. The source record shows D-660-25 and D-660-45, so it suits owners who face smog inspections.

Does an air oil separator need a tune or an Accessport?

No. COBB lists no tuning requirement, because the part manages crankcase vapors rather than changing fueling, boost or timing. It works on a stock WRX as well as a tuned one, and COBB notes that the larger holding capacity lets an engine make more power before the can risks overfilling.

What does the coolant connection on the separator do?

The back plate routes engine coolant through the unit so the whole can runs at roughly engine temperature. COBB explains that the heat evaporates water collecting inside, so less moisture mixes with the trapped oil. A built-in bleeder valve lets you purge air from that coolant circuit after installation.

Why choose the COBB Tuning Air/Oil Separator for VA Subaru over a basic catch can?

The COBB Tuning Air/Oil Separator for VA Subaru gives each FA engine vent port its own inlet, which COBB says clears crankcase pressure faster and lowers system pressure. A snail-shaped base swirls vapor for better drainage, and the unit adds integrated ORB ports, a coolant-heated body and about 1 liter of capacity.

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Description

COBB Tuning Air/Oil Separator for VA Subaru WRX

COBB Tuning’s Air/Oil Separator for VA Subaru WRX models answers a problem every direct-injected FA20 owner eventually meets: oil mist from the crankcase finding its way back into the intake. Developed with IAG Performance, it gives each of the three engine vent ports a dedicated inlet into a cast aluminum can of roughly 1 liter, heated by engine coolant so water boils off instead of emulsifying with the oil. It carries CARB EO numbers, so it is 50-state legal. It is sensible insurance on a stock sedan and earns its keep fastest on a tuned WRX with more boost and more blow-by.

Design and Performance

The FA engine vents crankcase pressure through three ports, one on each cylinder head and one on top of the block, and this unit plumbs each of them separately. COBB says that clears pressure faster and lowers overall system pressure. A snail-shaped base turns incoming vapor into a swirl so oil drops out and drains to the bottom, which keeps it from lowering effective octane or adding to carbon buildup on the intake side.

Features

Approximately 1 liter holding capacity from a 4 in OD by 5.75 in tall body
Three dedicated inlets, one for each FA engine crankcase vent port
Snail-shaped base that swirls incoming vapor for better oil drainage
Coolant-heated back plate to evaporate collected water
Integrated coolant bleeder valve
Integrated ORB ports
Compact cast aluminum tank with wrinkle black powder coat
Bespoke COBB anodized caps and laser-etched COBB logo
Developed in partnership with IAG Performance

Applications

Subaru WRX: VA | 2015-2021 | Sedan, 6MT and CVT, USDM

Notes

The Air/Oil Separator for VA Subaru WRX is not confirmed for the WRX STI or for 2022 and newer VB models
50-state legal with CARB EO D-660-25 and D-660-45 when installed per the application guide
No tune or Accessport is required for this part

Frequently Asked Questions

Will the COBB Tuning Air/Oil Separator for VA Subaru fit a WRX STI? No. COBB confirms the Air/Oil Separator for VA Subaru WRX models only, covering 2015 to 2021 USDM sedans with the manual gearbox or the CVT. It is built around the three crankcase vent ports of the FA engine, and the WRX STI from those years is not on the confirmed application list.
Is this separator legal to run in California? Yes. COBB lists it as legal for sale and use on emissions-controlled vehicles in all 50 states when installed according to the application guide, because it carries California Air Resources Board Executive Order numbers. The source record shows D-660-25 and D-660-45, so it suits owners who face smog inspections.
Does an air oil separator need a tune or an Accessport? No. COBB lists no tuning requirement, because the part manages crankcase vapors rather than changing fueling, boost or timing. It works on a stock WRX as well as a tuned one, and COBB notes that the larger holding capacity lets an engine make more power before the can risks overfilling.
What does the coolant connection on the separator do? The back plate routes engine coolant through the unit so the whole can runs at roughly engine temperature. COBB explains that the heat evaporates water collecting inside, so less moisture mixes with the trapped oil. A built-in bleeder valve lets you purge air from that coolant circuit after installation.
Why choose the COBB Tuning Air/Oil Separator for VA Subaru over a basic catch can? The COBB Tuning Air/Oil Separator for VA Subaru gives each FA engine vent port its own inlet, which COBB says clears crankcase pressure faster and lowers system pressure. A snail-shaped base swirls vapor for better drainage, and the unit adds integrated ORB ports, a coolant-heated body and about 1 liter of capacity.

About COBB Tuning

COBB Tuning was founded by Trey Cobb in 1999 in Rockwall, Texas, as a Subaru performance shop in the back of his father’s tire shop, and is now headquartered in Austin, Texas. In 2004 COBB introduced the Accessport, a handheld ECU tuning device that flashes COBB’s off-the-shelf maps or a custom tune and doubles as a real-time gauge and datalogger. The range has since grown from Subaru to Ford, Volkswagen, Audi, Porsche, Nissan, Honda, Mazda, Mitsubishi and Toyota platforms, with intakes, intercoolers, exhausts and flex fuel kits engineered alongside the tuning, and many COBB parts carry California Air Resources Board Executive Order numbers for use in all 50 states.

Additional Information

The Bulletproof Automotive website contains many thousands of products purchased in multiple different currencies. All of the prices are entered manually and accurately at the time of entry. Due to the consistently fluctuating international exchange rates, at times prices may not be able to be honored at their original intended rate. We apologize for any inconvenience this may cause, unfortunately our website is unable to compensate dynamically for what can at times be volatile changes in the cost of items due to currency values fluctuating, changes in prices from suppliers, changes in shipping and import duties, and other factors. Rest assured that any order you place on line will be at zero risk to you in this area. If in the event your order cannot be fulfilled at the original intended website price we will offer you a 100% refund, no questions asked. We will continue to do our best to maintain updated prices and we will always continue to offer our price match guarantees as well to ensure our prices are always the best for you. In short, prices may change without notice. It is always advised to give us a call prior to placing your order online to confirm availability and to confirm current pricing.

Shipping Policy

Items that are in stock in the US, either at Bulletproof’s warehouse or at a supplier’s warehouse, are generally delivered within 7-10 days. Special order items from overseas take considerably longer. As a courtesy Bulletproof offers delivery estimates to our customers which take into consideration manufacturer availability and shipping schedule. These estimates represent our best guess based on previous orders from the manufacturer and do not in any way imply a guaranteed delivery window. Many manufacturers work in a “just in time” inventory system and often take 2-20+ weeks to produce an item once an order is submitted. All deliverable items are then sent to our Japanese warehouse. Bulletproof ships a minimum of one full ocean freight container every month from Japan, oftentimes more than one a month. Ocean freight takes an average of 4 weeks. Typically it breaks down to one week in Japan for paperwork and customs, two weeks by boat and one week in US customs/clearance. Due to the wide number of variables between manufacturer and shipping schedules, delivery estimates are simply just that – estimates. We attempt to estimate conservatively and we usually deliver faster than our estimates suggest. It is not Bulletproof’s policy to guarantee delivery time of any special order item, this is impossible for us to do. By ordering you acknowledge that there is no required delivery ETA and an order may not be canceled or altered due to manufacturing or shipping delays, all ETA’s are provided as a best guess only. Please review the full Terms & Conditions here.

BP Pricing Difference

We do pricing a little differently on our JDM brands and we believe in making things simple and clear. No hidden fees or surcharges. Every price you see includes the shipping cost to our office in Los Angeles, California and all the associated taxes/duties/fees for bringing the products into the US. The only shipping you ever pay is from our facility in the US to your location. Be wary of resellers that don’t include the cost of international shipping in their pricing on JDM parts. While we believe we’ll always have the lowest all-in price on JDM products, we offer a price match guarantee for all authentic parts purchased from authorized dealers as well. For many international customers, it’s much more affordable to ship from the USA than from Japan directly, as the air freight and ocean freight costs are typically much less. However, for customers looking to ship directly from Japan outside of North America, or domestically in Japan, we can provide pricing specifically for that scenario. Please do not hesitate to contact us with any pricing questions or concerns. Please email us at sales@bulletproofautomotive.com with any inquiries.

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COBB Tuning Air/Oil Separator for VA Subaru WRX [843615]

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COBB Tuning Air/Oil Separator for VA Subaru WRX

Design and Performance

Features

Applications

Notes

Frequently Asked Questions

About COBB Tuning

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