AMS EJ25 Subaru Intake Manifold Uncoated Subaru 2002-2014 WRX / 2004-2021 STI


SKU AMS.31.08.0001

The AMS Performance EJ25 Intake 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
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