AMS Performance Intake Manifold 2004-2021 STI

The AMS Subaru Intake Manifold was designed to outperform the competition. We referenced many modern design examples and engineering studies to bring you the best intake manifold available for the Subaru EJ20 and EJ25 WRX & STI. After extensive testing we ended up with a manifold that makes more power than anything else currently available on the market!

Benefits

• 4.5 Liter Plenum Volume
• 13” Equal Length Intake Runners (Measured from Face of Bellhorn to End of Runner)
• 2.5” (63.5mm) Intake Runner Diameter (ID of Bellhorn)
• Bellhorn OD 3.8” (96.7mm)
• Increased Port Size at Cylinder Heads Allow Matching to Larger Hand Ported or CNC Ported Cylinder Heads
• Available in Standard or Reversed Configuration
• Throttle Body Opening Accepts Larger Throttle Bodies up to 2.625” (66.675mm) or 70mm with mild porting
• Available in 4 Configurations (Standard, Standard Coated, Reversed, and Reversed Coated

Product Notes

• Due to the large variety of rotated turbo kits on the market, we cannot guarantee fitment with every brand. Depending on the turbo location and sizing, interference with the cylinder 3 intake runner is possible.
• Some port matching may be required when used in conjunction with CNC or hand ported cylinder heads.
• The intake manifold is available with a standard or optional reverse throttle body orientation, allowing for more direct intercooler pipe routing.
• 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, but cable throttle bodies can be used with custom fitting and flange adapter.
• Standard configuration intercooler piping will need mild custom fabrication due to placement of throttle body.
• Reversed configuration requires the relocation of the alternator and removal of the A/C compressor. Installation is not a direct bolt on and will require custom intercooler piping.
• The intake manifold is designed to use a common Subaru aftermarket top feed injector size. (48mm overall length / 11mm inlet – standard Subaru rail size / 14mm outlet) We recommend the use of Injector Dynamics brand injectors.
• Standard Subaru style injectors cannot be used. (Side Feeds, Stock STI Style Injectors)
• Not compatible with side feed to top feed conversion rails
• Requires aftermarket rails and lines, will not fit with stock
• Not compatible with top mount intercoolers.
• Not directly compatible with mounting the factory upper coolant reservoir. Custom bracketry will need to be fabricated to mount.
• The bottom of the center plenum features four 1/8″ and one 1/4″ NPT ports for vacuum accessories.
• 2008+ STI may require mild clearancing of A/C compressor line

For the Subaru EJ Intake Manifold the plan was simple, take our years of engineering experience and design the best intake manifold available. Designed, prototyped, and tested in house by our team of Engineers, the AMS Subaru EJ Intake Manifold was created to be the best unit available on the market. By casting this manifold it is not only stronger, but it allowed us to optimize the power output by giving us the freedom to sculpt the interior geometry for maximum efficiency and airflow.