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AMS EJ25 Intake Manifold - Subaru Models (inc. 2002-2014 WRX / 2004+ STI)
AMS EJ25 Intake Manifold - Subaru Models (inc. 2002-2014 WRX / 2004+ STI)
AMS EJ25 Intake Manifold - Subaru Models (inc. 2002-2014 WRX / 2004+ STI)
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AMS EJ25 Intake Manifold

Subaru Models (inc. 2002-2014 WRX / 2004+ STI)


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Features & Product Details

RallySport Direct proudly carries performance products brought by you by the record holders at AMS Performance. 

Here, you are looking at the AMS Performance EJ25 Intake Manifold. This manifold has been designed for those looking for the right intake manifold to accommodate big horsepower setups. AMS utilized computational fluid dynamics software and the result is a larger plenum size of 4.5L for more top-end power, along with CNC machined bellhorns which act as internal velocity stacks which will allow for a broader power curve and high RPM horsepower capabilities. 


  • 4.5-liter plenum volume
  • 13" Equal length intake runners measured from the face of bellhorn to end of the runner
  • 2.5" (63.5mm) intake runner diameter
  • Bellhorn OD 3.8" (96.7mm)
  • TGV housing replaced with long runner design
  • Increased port size at cylinder heads allow matching to larger hand ported or CNC ported cylinder heads
  • Throttle body opening accepts larger throttle bodies up to 2.625" (66,675mm) or 70mm with mild porting
  • This version intake manifold is available with a standard orientation
  • Bottom of the center plenum features 4-1/8" and 1-1/4" NPT spots for vacuum accessories
  • Uncoated, textured ted, gold, bronze, black, and blue colors available


  • Some port matching of the manifold may be required when used in conjunction with CNC or hand ported cylinder heads
  • Larger throttle bodies can be used with proper modifications (up to 70mm with minor porting, larger throttle bodies may also require adapter flanges)
  • The intake manifold is flanged for 04+ STI drive by wire throttle bodies, other models (such as 08-14 WRX) require a change to the STI style throttle body
  • Cable throttle bodies (such as 02-05 WRX) can be used with custom fitting and flange adapter
  • Standard configuration intercooler piping will need mild custom fabrication due to placement of throttle body
  • Designed to use common Subaru AFTERMARKET top feed injector size (48mm overall length / 11mm inlet-standard Subaru rail size / 14mm outlet)
  • Not compatible with OEM subaru injectors
  • Not compatible with stock fuel rails or lines, requires aftermarket top feed rails and lines
  • Not compatible with top mount intercoolers
  • Not compatible with hard pipe stock location turbo inlets, requires silicone inlet
  • Not directly compatible with mounting the factory upper coolant reservoir


    Brand: AMS
    Finish: Powder Coated
    Installation Hardware Included: No
    Material: Aluminum
    Mfgr. Warranty: No Warranty
    Condition: New Product
    Return Policy:



    1 Reviews
    5 out of 5 Stars
    5 Stars
    4 Stars
    3 Stars
    2 Stars
    1 Stars
    Customer Photos and Videos
    AMS EJ25 Intake Manifold ( Part Number:  31.08.0001)
    Beautiful  2 years ago
    5out of 5stars
    Stars and Cars
    I bought this manifold to help add more air flow to my build, also to spice things up under the hood. And has surpassed all my expectations in those regards. Not having separate TGV housing and gaskets make for a simpler all around look. It goes without saying this also eliminates a potential failure point although oem isn’t pron to issues in that area. There is a vacuum npt fighting on the top of the driver side runner above cylinder 4 for the brake booster. I was not aware of this when I purchased but this made switching over that much easier. The npt ports on the bottom of the manifold are in the perfect location to hide the ugly lines for the boost controller, regulator etc. With a beautiful powder coating and a shaved look, you cannot go wrong with this manifold. I would how ever suggest you to be ready to pick up a few other items to make it work. I ran into a few fitment issues with the other parts I was running such as my front mount. You cannot run this with the stock bypass valve location on the ets piping kit. You also much have aftermarket fuel rails and need to find or make a bracket for the coolant overflow tank. I’m sure I have missed things but I can say this was money well spent.
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    • Q: Fuel injector fitment  Clafond96 3 years ago

      Do the iag 2600cc injectors in the kit iag-afd-261 fit in this intake manifold
    • Q: Adapter for cable throttle?  crankyfart3 years ago

      Do you guys sell the adapter or flange that is required for using this intake manifold with a cable throttle?
    • Q: AMS Manifold height  trevspice444993 years ago

      Can you tell me what the overall height of the AMS manifold is? I'm trying to figure out whether it's tall than the Process West with tgvs. Thanks.
    • Q: vacuum  Subie_sibs_3 years ago

      was wondering what vacuum lines are deleted with this would it be worth buying a 3" turbo inlet
      • 0 of 0 people found the following answer helpful

        A:  you should be able to keep all of your vacuum systems, now the solenoids and lines may not be able to be mounted up like stock, but with the ports on the bottom of the manifold, there should be no reason you would have to delete any of those. In regards to the inlet, it really depends on the turbo you are wanting to run and how much power you want to make. If you're going with a large frame turbo, I think the 3inch inlet is worth it for the added air flow. Thanks!

        Rick C. @ RallySport Direct 3 years ago  
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    • Q: Retain AC?  2010 White STI3 years ago

      Are you able to retain working air conditioning?
      • 0 of 0 people found the following answer helpful

        A:  I am not aware of this disabling the AC.

        Brady R @ RallySport Direct 3 years ago  
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      • 0 of 0 people found the following answer helpful

        A:  On my 2015 I had no issues with the AC lines. If I remember correctly I mildly bent one out of the way for more clearance.

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