GrimmSpeed® (08-21) WRX/STI/Forrester/Legacy/Outback Cabin Panel Air Filter

Regular price$69.00
Shipping calculated at checkout.
  • In stock, ready to ship
  • Question? Call us at (888) 257-1077 🏁
  • Free Shipping USA (Exc. HI, AK, PR)
  • This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

    Compatible: (2.0L/2.5L)

    2008 - 2021 Subaru WRX

    2008 - 2018 Subaru WRX STI

    2009 - 2018 Subaru Forrester

    2013 - 2017 Subaru CrossTrek

    2005 - 2017 Subaru Legacy

    2005 - 2017 Subaru Outback




    Better Flow, More Power!

    At GrimmSpeed we know that not everyone is ready for one of our full aftermarket intake systems, but still wants a safe and easy way to increase power with no tuning required. We worked hard to develop a direct replacement, dry-element air filter for the stock airbox that not only decreases restriction, producing more torque and horsepower, but is also able to filter out particulates at the same level as the OEM filter to keep your engine safe.


    • Direct OE Replacement – Drops right into the OEM airbox for an easy install
    • Oil-Free Element – Dry-Con means more reliability and easier maintenance
    • Proven Performance: Designed in the Lab, Proven on the Dyno
      • Tested +9 TQ and +6 WHP – Safe, reliable power gains 
      • 62% Better Flow than OEM – More flow/less restriction, equals more power
      • 99.1% Efficiency – Filters at the same level as OEM
      • Long Service Life – Up to 20K mile service interval 
    • Serviceable/Reusable – Simple refresh using popular cleaning kits
    • No Tune Required – Simply drop in and enjoy more safe, reliable power!
    • 1 Year Warranty – Worry free, heavy-duty construction
    • 100% Made in the USA



    Filter design is a delicate balancing act, the overall goal of creating a good air filter is to find the ideal combination of flow, filtration efficiency and holding capacity. There IS a difference between simply making a unit that fits in a factory intake box and engineering a performance air filter.

    Some air filters are constructed with a cotton or synthetic media combined with an oil to increase filtering ability. This can increase flow, however it also means more difficult filter maintenance because of the need to properly re-oil the filter. We decided to use a dry-construction media, utilizing two different layers of synthetic material with varied filtering and flow abilities, resulting in very similar flow capability to the oiled media while maintaining the same filtering efficiency. Since other important variables in air filter design including the pleat pitch, count and depth can make or break the performance of a filter, extensive testing was required.

    We contracted a 3rd party OEM Test Lab using SAE-5011 OEM Air Filter Standards for our initial filter designs. All of these were the same size and fitment, but used varied filter media including pleat pitch, count, depth, material and construction. 

    The first data set explores pressure drop across the filter before and after saturation since it directly relates to the performance potential of the filter. Chart 1 shows that the pressure drop of all clean and dirty filters was very similar, identifying the filtering ability of each panel. The next data set focuses on the filtration ability in each filter; Chart 2 illustrates that filters A and B allowed far too much of the test dust to flow through, with filter C being the optimal candidate for additional performance-based testing. We took the general construction of this unit and modified it into 3 different pleat variations.


    Since ultimate performance of an air filter is based on its flow ability, we wanted to see how different pleat packs would compare to the OEM filter in terms of CFM through the filter as well as dust capacity. Chart 3 illustrates that as flow increases, capacity decreases. We see that the performance of the filters has substantially increased over the OEM unit, at the slight cost of reduction in dust capacity. Arguably the most important criteria of the filter is its ability to resist the flow of contaminants. The OEM filter was found to filter at 99.7%, with all three of our test filters scoring almost identically with 99.2% or above as illustrated in chart 4. All of these filters would be exceptional choices.



    After this very comprehensive testing, we were able to select a design that meets the GrimmSpeed standard and best balanced the ultimate flow potential with the dust holding capacity as illustrated in Chart 5. This filter maintains the same efficiency as OEM, but has an increase in CFM by 62%. The reduction in dust holding capacity is an acceptable middle ground between the filter choices and will still retain a lengthy maintenance interval.




    In order to properly evaluate the performance gains of The GrimmSpeed Dry-Con Air Filters, we did four wide open throttle pulls with the OEM air filter, then four more with our unit on a 2020 factory-tuned STI test car. The outlier run was thrown out and results were averaged as shown in Chart 6. We can see a solid 9 ft/lbs of torque difference and a consistent 6 whp gain from 5400rpm until redline with the GrimmSpeed filters. There is reduction in restriction in the top end that shows well here and has a direct relation to the performance of the air filter.




    The GrimmSpeed Dry-Con Air Filter flows an amazing 62% better than OEM, features a 99.2% efficiency and is easy to service without the added hassle of proper re-oiling. Through testing, we saw an increase of 9 ft/lbs of torque and 6 whp at the top end of the RPM range with no engine tuning involved.

    GrimmSpeed was founded in 2006 to provide customers with innovative and highly engineered aftermarket products. On a more personal level, we are a group of car enthusiasts in the lovely city of Minneapolis, Minnesota who are absolutely passionate about what we do. Our bread and butter started out anything Subaru. However, after growing our team and engineering expertise, we started developing products for Mitsubishi, Ford, MazdaSpeed, and Hyundai markets. We are a true garage start-up (single stall townhouse garage in Maplewood, MN) and we've been lucky enough over the years to be able to turn it into exactly the business we had dreamed of....actually, much more. We have a wide breadth of product offerings including: intercoolers, exhausts, intakes, gaskets, engine pulleys, phenolic spacers, boost controllers, and many more.

    Most of our decisions at GrimmSpeed are based on 3 basic principles:



    1. Innovation

    Our team knows that if they propose a project there has to be at least one new innovative feature. It may be a completely new idea or an innovation to a current product on the market. We truly love creating products that really work and make an impact on the enthusiast community.



    2. Keeping Jobs in Minnesota

    Lets face it, manufacturing in the US has been lost for a long time. It's sad because manufacturing is what this great country was founded on. Our goal is to do our part in bringing it back to the US. Lets show the rest of the world that we do still 'have it'. Almost all of our partners are right here in Minnesota, most of which are within an hour drive of us.  Its not always about the $$ and we are here to prove that.



    3. Customer Service You Deserve

    What flies for customer service these days just continues to astonish us. We don't have to tell you guys, I'm sure you are all well aware of some of the terrible customer service that goes on these days, especially in our industry. Our goals are to be honest with you, if something is going to be delayed, we aren't going to give you some made up date when it will be ready....we will tell you exactly the most current info we have. If you need help installing our products we will be there on the phone or email ready to help until you have figured out the issue. Last but not least, we will keep our word. If we say we are going to call you back, we actually will. 

    -Justin Grimm