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GrimmSpeed Air Oil Separator (Part Number: )
GrimmSpeed Air Oil Separator (Part Number: )
GrimmSpeed Air Oil Separator (Part Number: )
GrimmSpeed Air Oil Separator (Part Number: )
GrimmSpeed Air Oil Separator (Part Number: )
GrimmSpeed Air Oil Separator (Part Number: )
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GrimmSpeed Air Oil Separator (Part Number: )
GrimmSpeed Air Oil Separator (Part Number: )
GrimmSpeed Air Oil Separator (Part Number: )
GrimmSpeed Air Oil Separator
Subaru WRX 2008-2014 / Legacy GT 2005-2012
Read 10 Reviews | 13 Q&As
Part # 078016

In stock! Ships same day

Features & Product Details

The Grimmspeed Air-Oil Separator (AOS) is one of RallySport Direct's highly sought after items. Grimspeed uses a unique patent pending design which allows you to maintain your PCV valve while separating oil from the air in both the heads and crankcase. These boxer engines have inherent issues with harmful oil and vapors getting into the intake system of your vehicle which can cause issues like having an effect on the octane rating with your gas, and after long periods of use and mileage can cause buildup on your valves.

This particular air-oil separator takes the place of an oil catch can, or a tank which is convenient to eliminate the need to empty the catch can. This is a subtle installation that replaces your factory oil filler cap.

New lines, fittings, and zip ties will be included to make this catch can system ready for the installation. 

Note that this particular unit will come in the anodized black finish for protection against corrosion, and to add a nice touch to the theme of your engine bay. 


Brand: GrimmSpeed
Color: Black
Installation Hardware Included: Yes
Material: Aluminum
Mfgr. Warranty: Lifetime
Condition: New Product
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



10 Reviews
4.6 out of 5 Stars
5 Stars
4 Stars
3 Stars
2 Stars
1 Stars
Customer Photos and Videos
GrimmSpeed Air Oil Separator ( Part Number: 078016)
GrimmSpeed Air Oil Separator ( Part Number: 078016)
GrimmSpeed Air Oil Separator ( Part Number: 078016)
great product 1 year ago
5out of 5stars

Chose this because of the stealthy look inside engine bay. Works great. No more oil in the intake tube!
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great product but... 3 years ago
3out of 5stars

got this AOS for my birthday and finally got the chance to install it. while installing it and looking through the install manual and videos. definitely would not recommend following it to the tee... if you have a 2011-2014 wrx. instructions made no sense for the system to breath properly. if you look at all the components they are plugging up and how the system is suppose to work, it makes not sense. do follow the first few instructions (taking off the intercooler). disconnect the left cylinder head vent hose and connect it to the T spliter provided. cut a small hose and connect the T back to the white connector that you just disconnected, and the last T goes to the AOS on the most outer. dont disconnect the right side hose in front of the turbo cause that hose actually goes all the way to the white connector you disconnected and connected to the T splitter. you do not need to disconnect the connector behind the intake manifold, but you do need to disconnect the hose under the intake manifold off the black connector but DO NOT PLUG up the hose. instead of plugging it you will need to route a hose from the AOS middle connection to that hose. this hose goes to your intake system (suppose to be clean air coming from the AOS). on the black connector that you disconnected from the intake hose under the intake manifold, you will want to pivot it upwards or towards the firewall. connect the hose to the black connector and route it to the last port on the AOS. then you button it up.
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Awesome 4 years ago
5out of 5stars

Product show up fast. Install way easy. A must for wrx. Thx rsd
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Great Product 5 years ago
5out of 5stars

Like this product, looks great, and it could be just me, but motor seems to run a little bit smoother than before. Install took over 3 hours though, ensuring every connection was the proper one. Had to use two different resources to complete the job, used a 2008 WRX install Youtube video and the Grimmspeed PDF.....used the video primarily until about 3/4 of the way in, then used the PDF to finish the job. Took my time, swapping oil routing hoses to the engine block is NOT something to rush. But, glad I got it installed, no CELs afterward, engine running like a champ, 2014 WRX.
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1 of 1 people found the following review helpful
Works perfectly! 5 years ago
5out of 5stars

Almost 8 months later and my turbo side is DRY! Works just as stated!
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  • Q: Grimmspeed Air Oil Separator  NinjaGil3 months ago

    Will this AOS Grimmspeed work on higher horsepower like between 400hp to 700hp? or do I need something bigger like the IAG or Perrin AOS?
    • 0 of 0 people found the following answer helpful

      A:  We would not recommend this for higher horsepower builds. You would want to go something like the IAG AOS.

      Luis L. @ RallySport Direct 3 months ago  
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  • Q: Installation  Kuroi7 months ago

    Does the installation change if you have a DIT setup?
    • 0 of 0 people found the following answer helpful

      A:  This AOS is actually not confirmed for the 15+ models. Install will be somewhat similar, but make sure to use the instructions from the specific kit that you end up using, as it can vary a little from kit to kit.

      Marcus E. @ RallySport Direct 6 months ago  
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  • Q: Would this work on a 2006 wrx, obviously with a different hose setup?  Ian10 months ago

    Is there any difference between this model and the model for the 02-07 wrx besides the items it comes with?
    • 0 of 0 people found the following answer helpful

      A:  The Air Oil Separator is the same but the lines and fittings are different. There is a Grimmspeed AOS kit that is made specifically for 02-07 and STI models. Model # GRM 078006

      Karsten B. @ RallySport Direct 9 months ago  
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  • Q: 2014 Forester XT  Michael Hill2 years ago

    I am having difficulty finding an AOS for my wife's Forester XT and I was wondering if this one would work? As far as I can tell they would just need to have the same oil cap threads per inch and pitch which I think they do.
    • 0 of 0 people found the following answer helpful

      A:  Unfortunately we cannot confirm this to work with your wife's XT. I would do some additional research and see if anyone has found a modification to make these work.

      Tyler A. @ RallySport Direct 2 years ago  
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  • Q: How to fill in oil?  sammygress253484 years ago

    since this takes place of oem oil cap how do you refill oil back into the engine? Does the AOS come apart?

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