Does the Air/Oil Separator Kit for GD fit the 2015 to 2021 STI?

Yes. GrimmSpeed lists the Air/Oil Separator Kit for GD WRX models across every EJ257 STI from 2004 through 2021, covering the GD, GR / GV and VA chassis. The 2004 to 2008 SG Forester XT and the 2004 to 2006 Baja XT are also on the fitment list.

Can I run the GrimmSpeed AOS with a front mount intercooler?

Yes. The GrimmSpeed install guide covers front mount intercooler cars: instead of connecting to the OEM head breather hardline, the bottom right port runs to the existing tee for the head breathers. Top mount cars follow the standard routing, which includes a connection at the intercooler hard pipe.

Is the factory PCV valve kept with this separator?

Yes. The GrimmSpeed recommended installation retains the factory PCV valve. The separator sits at the oil fill and joins the existing breather hoses using three supplied hose fittings, two connectors, a cap and 8.5 ft of hose, so no extra plumbing needs to be bought.

Does the GrimmSpeed separator need to be drained?

No. GrimmSpeed calls the design maintenance free: it coalesces oil out of the ventilation air without mesh media, and there is no catch can to check or empty and no oil to replace afterwards. The only service parts are its O-ring seals.

Is this AOS suitable for a built EJ257?

Not necessarily. GrimmSpeed states the separator is designed to combat factory amounts of blow-by and may not work on a built motor or an engine with abnormal oil consumption. A built EJ257 running much more boost generally produces more crankcase pressure than this unit was sized for.

Description

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BP PRICING DIFFERENCE

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Description

GrimmSpeed Air/Oil Separator Kit for GD Subaru WRX, GD, GR / GV and VA STI, SG Forester XT, and Baja XT

The GrimmSpeed Air/Oil Separator Kit for GD Subaru WRX and every EJ257 STI from the 2004 GD through the 2021 VA, plus the SG Forester XT and Baja XT, strips oil from crankcase and head ventilation air so it is not fed back through the turbo inlet. Its billet aluminum body screws into the oil fill tube with the factory PCV valve left in circuit, so owners tired of draining a catch can get a part that looks after itself. GrimmSpeed sizes it for stock blow-by; an oil-burning or built engine may need a different solution.

Features

No catch can to drain or refill
Billet aluminum construction, fully machined, black or red anodized
O-ring seals the owner can replace
Retains the stock PCV valve in the recommended layout

What’s Included

GrimmSpeed billet air/oil separator
AOS hose fittings (x3)
1/2 in to 1/2 in hose connectors (x2)
1/2 in hose cap
8.5 ft of 1/2 in fuel hose
Zip ties (x8)

Applications

Subaru Baja XT: 2004-2006 | 2.5L EJ255
Subaru Forester XT: SG | 2004-2008 | 2.5L EJ255
Subaru WRX: GD | 2002-2007 | 2.0L EJ205 / 2.5L EJ255
Subaru WRX STI: GD, GR / GV, VA | 2004-2021 | 2.5L EJ257

Notes

Intended for factory amounts of blow-by; GrimmSpeed cautions that a built motor, or one with abnormal oil consumption, may not suit this separator
The Air/Oil Separator Kit for GD and later STI models screws loosely into the oil fill tube and is aimed toward the 11 o’clock position before the hoses are connected
On a car with a front mount intercooler, GrimmSpeed routes the bottom right port to the existing head breather tee instead of the OEM head breather hardline
This GrimmSpeed AOS does not fit the 2008-2014 WRX, 2005-2009 Legacy GT or Outback XT, or the 2009-2013 Forester XT, which use their own GrimmSpeed version

Frequently Asked Questions

Does the Air/Oil Separator Kit for GD fit the 2015 to 2021 STI? Yes. GrimmSpeed lists the Air/Oil Separator Kit for GD WRX models across every EJ257 STI from 2004 through 2021, covering the GD, GR / GV and VA chassis. The 2004 to 2008 SG Forester XT and the 2004 to 2006 Baja XT are also on the fitment list.
Can I run the GrimmSpeed AOS with a front mount intercooler? Yes. The GrimmSpeed install guide covers front mount intercooler cars: instead of connecting to the OEM head breather hardline, the bottom right port runs to the existing tee for the head breathers. Top mount cars follow the standard routing, which includes a connection at the intercooler hard pipe.
Is the factory PCV valve kept with this separator? Yes. The GrimmSpeed recommended installation retains the factory PCV valve. The separator sits at the oil fill and joins the existing breather hoses using three supplied hose fittings, two connectors, a cap and 8.5 ft of hose, so no extra plumbing needs to be bought.
Does the GrimmSpeed separator need to be drained? No. GrimmSpeed calls the design maintenance free: it coalesces oil out of the ventilation air without mesh media, and there is no catch can to check or empty and no oil to replace afterwards. The only service parts are its O-ring seals.
Is this AOS suitable for a built EJ257? Not necessarily. GrimmSpeed states the separator is designed to combat factory amounts of blow-by and may not work on a built motor or an engine with abnormal oil consumption. A built EJ257 running much more boost generally produces more crankcase pressure than this unit was sized for.

About GrimmSpeed

GrimmSpeed began in 2006 in a single-stall garage in Maplewood, Minnesota, porting and polishing Subaru manifolds. After building parts for several other makes, the company narrowed its focus back to Subaru, and its range now covers intercoolers, charge pipes, intakes, bypass valves, headers, up-pipes, catback exhausts, turbochargers, brake caliper kits, drivetrain mounts and titanium engine bay parts for the WRX, STI, Forester XT, Legacy GT, Ascent and BRZ, along with the Toyota 86 and GR86. GrimmSpeed engineers and manufactures as much of that range as it can in-house, and its front mount intercoolers are welded and inspected by hand in the USA.

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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GrimmSpeed Air/Oil Separator Kit for GD Subaru WRX, GD, GR / GV and VA STI, SG Forester XT, and Baja XT

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GrimmSpeed Air/Oil Separator Kit for GD Subaru WRX, GD, GR / GV and VA STI, SG Forester XT, and Baja XT

Features

What’s Included

Applications

Notes

Frequently Asked Questions

About GrimmSpeed

Reviews