GrimmSpeed (AOS) Air/Oil Separator - 02-07 Impreza WRX, 04-14 Impreza WRX STI, and 15+ WRX STI

Regular price $299.00 USD Sale price $299.00 USD Regular price $299.00 USD
Anodized Finish Black
Special order - Ships in 8+ weeks
SKU: grm078006
Product Description
The Grimmspeed AOS (Air Oil Seperator) is a compact upgrade that does the job of combating the factory's blow-by problem; this is a common problem in Subaru EJ25 motors and can cause the dreaded ring land issue.

Most systems implement a complex and cumbersome system with an actual oil catch tank, the Grimmspeed system is a much simpler inline kit that replaces the oil cap*. This kit basically keeps oil away from the engine's ventilation system, this way you'll have a cleaner air intake system without oil going through it.

As a result, you will experience the following:
  1. Consistent oil octane
  2. Reduced chances of engine knock (detonation)
  3. Reduced oil consumption
  4. Cleaner emissions and MPG

  • Subaru Impreza WRX [GD/GG] (2002, 2003, 2004, 2005, 2006, 2007)
  • Subaru Impreza WRX STi [GDB] (2004, 2005, 2006, 2007
  • Subaru Impreza WRX STi [GRB/GVB] (2008, 2009, 2010, 2011, 2012, 2013, 2014)
  • Subaru WRX STI [VAB] (2015, 2016, 2017, 2018)
*Recommended for OEM, Stage 1, or Stage 2 builds. For Stage 3 and High Horse power builds a AOS with catch tank is recommended


Compact system
Helps ensure engine longevity
Ideal for OEM, Stage 1, and Stage 2 builds
Available in 3 finishes
Made of Anodized Aluminum for looks and endurance
A must have for all EJ25 Turbo Motors

Extended Information

Type: Air Oil Separator
Catch Tank: Not included
Design: In line with PCV system
Finish: Black, Blue, or Red
Material: Aluminum

To provide faster delivery and turn around time; Kami Speed ships products out from different warehouses throughout the United States. Usually averaging 1-4 business days for processing prior to shipping.

Depending on the package, we ship using different carriers according to the item's location, content, and size.

Freight truck & international items, will require up to 7 business days to ship due to size and logistics.

All orders made after 3:00pm ET will be shipped or processed the next business day.

Unless otherwise noted as "In Stock" or exact ETA. Special Order items have an ETA of 5+ weeks.

Orders over $500 will ship insured and over $1,000 with signature and insurance in order to guarantee delivery. Orders over $1000 may not be able to ship to a different address not listed as the billing address or confirm payment address from the form of payment used. Orders with suite numbers, different billing, or apartment numbers will require signature if valued over $100.

All international orders outside of the USA are subject to duties and taxes fees per your countries jurisdiction and determined by customs.
Kami Speed serves the right to ship using an alternative method if we see it fit, in order to expedite shipping and reduce your rate depending on product value.

Processing and logistics on in stock international orders can take up to 7 business days to process & ship.

In stock, non special order items can be returned within 30 days of the product arriving to your house or place of work.
Returns will NOT be accepted on Clearance Items, Final Sales, Special Orders, Opened, Installed, Incomplete, or Otherwise Used Products. In order to initiate a return, an RMA number must be requested and approved via e-mail. All returns will be subject to a 20% restocking fee minus complete shipping cost (roundtrip).

Any processed orders that have not shipped will incur a 6% cancelation refund fee unless the product was not available to ship within a timely manner. No fee will be incurred if used as store credit.

For complete details on our return policy, please see our Help and FAQ link under HELPFUL INFO.

WARNING: Operating, servicing and maintaining a passenger vehicle or off-highway motor vehicle can expose you to chemicals including engine exhaust, carbon monoxide, phthalates, and lead, which are known to the State of California to cause cancer and birth defects or other reproductive harm. To minimize exposure, avoid breathing exhaust, do not idle the engine except as necessary, service your vehicle in a well-ventilated area and wear gloves or wash your hands frequently when servicing your vehicle. For more information go to

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