GrimmSpeed Air Oil Separator Red

Part #: GRM 078006R
MSRP: $314.99
( 20 reviews )



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Return Policy | Shipping


This product is covered by our
RallySport Guarantee
No questions asked 30 day return policy


Brand: Grimmspeed
Color: Red
Installation Hardware Included: Yes
Material: Aluminum
Mfgr. Warranty: 2 Years
Return Policy:

RallySport Guarantee - 30 Days

Items that are covered under the RallySport Guarantee offer a 30 day no questions asked return policy.

RallySport Guarantee items may be returned within 30 days of the original invoice date and must include all the original parts and contents for a refund.

The RallySport Guarantee does not apply to products that have been modified, damaged, misused or abused. All returns require an RMA (Return Merchandise Authorization) Number, and freight charges are strictly non-refundable. For more information regarding our freight refund policy, please refer to our return policy page found HERE.
RallySport Guarantee


Subaru Impreza
WRX STI 2004, 2005, 2006, 2007WRX STI Limited 2007WRX STI Hatchback 2008, 2009, 2010, 2011, 2012, 2013, 2014WRX STI Special Edition Hatchback 2010WRX STI Limited Sedan 2011, 2012, 2013, 2014WRX STI Limited Hatchback 2011, 2012, 2013, 2014WRX STI Sedan 2011, 2012, 2013, 2014WRX 2002, 2003, 2004, 2005, 2006, 2007WRX TR 2006, 2007WRX Limited 2006, 2007
Subaru Forester
XT 2004, 2005XT Premium 2005XT Limited 2006, 2007, 2008Sports 2.5 XT 2008
Subaru WRX STI
Base 2015

An Air/Oil (AOS) Separator has one job, remove the oil from the engine ventilation system so the oil does not get sent through the intake system. The GrimmSpeed AOS has a unique patent pending design that allows you to maintain your PCV Valve while separating the oil out of the crankcase and head ventilation air!

Removing oil out of your intake system will result in a more efficient engine. An Air Oil Separator takes the place of an oil catch can or tank, resulting in you not having to empty your oil catch can. As well as being very subtle and not noticeable.

Another benefit to this unique design is the compact and clean look; making this ideal for someone who wants to keep it looking stock under the hood.

REVIEWS ( 20 )



It works.
justme142176680 5 months ago
This product is very well built and it solves several issues in a stock WRX. My wife's 2011 STI is sporting one solving the old oil in the intercooler issue as well as a lean condition caused by the stock crank case breather setup emulsifying the oil and winter time moisture clogging the whole system. Looks cool, works great, worth every penny believe it or not. Grimmspeed is awesome if you weren't already aware.

Works great on our 2015 STI!
Rick C. 9 months ago
Works just like it should. It keeps our intake and intercooler free from oil and looks great while doing so!

2015 STI
wcrdroid22106 11 months ago
I installed this product on my 2015 STI several thousand miles ago. I installed it with clear reinforced PVC hoses so I could monitor its function. After 2000 miles of a combination of daily driving and really hard mountain driving, I noticed the center hose had a coating of oil on it (no pooling). I am not sure if this was due to the hard driving (hard right handed turns under boost), or if it had anything to do with my car being slightly over-filled with oil. I replaced the center hose with a new piece of clear hose and so far have no significant oil in the center hose after approximately 1500 miles (hose is almost completely clear with maybe a drop of oil in the bottom of the hose). My engine has consumed nearly 1/2 a quart of oil in 1500 miles, but it isn't going through the center hose of the AOS. The product is definitely doing what it is designed to do as the 2 lines going in are coated with oil, and the one going out is clean. I would recommend for daily driver, just be mindful of your boost levels when making sustained high-G right turns. I definitely recommend installing with clear lines to monitor oil in lines.

Nice, clean install on 2015 STI
15_STI 12 months ago
Currently running the Grimmspeed AOS on my 2015 STI. Firstly, the service from Rally Sport Direct was excellent. Super fast shipping to Australia. The AOS itself is a quality product, as always, from Grimmspeed. Very easy to install and if you take a bit of time to plan the path for the hoses, it looks very nice and tidy when you finish. Couldn't be happier with this maintenance free AOS solution :)
Verified Purchase
Loved it
pjn826 1 year ago
Bought this the same day I bought my 16g turbo. Had smoke coming out of the exhaust, then I slapped this on and smoke went away and my car is running perfect. Highly recommend this. Looks really nice under the hood also. GrimmSpeed did a really nice job once again.


  • AnswerQ: Instructions for fmic  xsaint7741060 3 months ago

    Are there directions for a fmic

    • A: If you have a FMIC, the instructions are identical except the bottom right port on the AOS will not go to the oem head breather hardline, it will go to your existing “T” for the head breathers.

      Brady R. 3 months ago

  • AnswerQ: what is the difference between this and Perrin/Crawford based AOS systems?  Evren 5 months ago

    if you could shed some light that would be great on my order decision. Thanks

    • A: This system routes blow by back to the oil feed tube, it is also unbaffled and not recommended due to the location for heavy track use. The Crawford and Perrin AOS systems are coolant cooled and work very well for track applications. This is a simple AOS that doesn't break the bank and is much easier to install than the other two.

      5 months ago

  • AnswerQ: tune  Tyson DesRoches 7 months ago

    does this require a tune?

    • A: Tuning will not be needed for any AOS system, as it does not effect the ECU or tuning calibrations.

      Brady R. 6 months ago

  • AnswerQ: fitment differences  TremendousWRX 9 months ago

    Is there any fitment differences between this AOS and the AOS specified for the 2008+WRX aside from hoses and connectors? I am wondering if I can buy this one, and buy some 1/2 inch fuel hoses and connectors, and swap it between the two cars.

    • A: This AOS body is the same as the other model and the only differences are the hoses and connectors. You could use this AOS on a 2008+ WRX if you sourced your own fittings and hoses.

      Zach G. 9 months ago

  • AnswerQ: supplied hose size  shiroikage 1 year ago

    What size is the hose supplied with the AOS? would you have the hoses in red to purchase along with the kit?

    • A: The hose supplied in this kit is 1/2. We currently do not offer the hose in any other colors than black. -Matt H.

      Grimm Speed 1 year ago