SKU: 17910804209

AMS Performance Subaru WRX / STI EJ Intake Manifold - Reverse Rotation, Coated (AMS.31.08.0002-2)

Sale price$674.98 Regular price$749.98
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Description

AMS Performance Subaru WRX / STI EJ Intake Manifold - Reverse Rotation, Coated (AMS.31.08.0002-2)Stay Ahead Of Your Competition With The AMS Subaru WRX STI Intake Manifold! 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

Stay Ahead Of Your Competition With The AMS Subaru WRX / STI Intake Manifold!

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

Engineered To Be The Best

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.

By utilizing Solidworks© & CFD (computational fluid dynamics) software we started with an extremely large plenum size of 4.5L for the ultimate top-end power. We also designed CNC machined bellhorns which act as internal velocity stacks and allow for a broad power curve and high RPM horsepower capabilities. This allowed us to optimize massive 2.5″ tapered runners and matched cylinder port angles to minimize turbulence and maximize power output. The 13″ length of the runners allow for a smooth taper in cross section reduction, giving the AMS Subaru EJ Intake Manifold exceptional flow.

Unmatched power gains and excellent response

This AMS Subaru EJ Intake Manifold offers more than just top end power. This manifold gives you an amazingly wide power-band with a huge jump in power whenever you are in boost. This equates to greatly improved lap times on the road course and the confidence to leave any opponent in your dust when on the drag strip!

Be the guy to beat, order your AMS Subaru EJ WRX / STI Intake Manifold now! 

Applications

  • 02-05 Subaru WRX w/ EJ20 (Requires adapter to use WRX style drive by cable throttle body)
  • 06-07 Subaru WRX w/ EJ25
  • 08-14 Subaru WRX w/ EJ25 (Requires using STI style drive by wire throttle body)
  • 04-Current Subaru STI w/ EJ25 (2008+ STI may require mild clearancing of A/C compressor line)
  • Will fit various Legacy and Forester EJ25 applications with proper throttle body usage and custom fitting
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 17910804209

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4.2 ★★★★★
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Toby
Port Orchard, US
★★★★★ 3
Great quality, a bit frumpy
Just ok. Probably should have returned these as I feel a bit like a grandma when I wear them, So they hang in my closet. Not super flattering but nice quality and fabric. Thickness is perfect. Style just isn’t for me but comfy
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on September 27, 2025
S
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Sharpshopper
Whiting, US
★★★★★ 5
Amazing Fit For Tall Senior Slim Person!
Fit Type: 33" Inseam, Size: Medium, Color: Lake Green
I usually wear a size 8 or 10 or medium. But being 5 foot 11 and weigh 145, it’s very hard to find pants that fit. These in medium are great lightweight and long enough that they touch the floor in the back. Being older I have extra weight in my stomach and waist, but the waist is wide and not tight. It fits nice in the back also and the rise is long enough. Great summer pants for our hot weather in Florida. Even if they do pill some, I have a gadget that removes any pilling so not worried about that. I got the medium in the teal color which is not as bright but a nice color.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 4, 2026
M
Verified Purchase
Monee Loyalty
Draper, US
★★★★★ 1
Pilling
I loved these pants very much when I first purchased them the fit was amazing and the length was even better. Pants are very flattering. I wore them for the first time a few days ago only for a couple hours and pilling happened immediately! I am very annoyed at that fact because I purchased these pants at the end of March and I am not in my return window! I am Not a happy customer at all. Waste of money
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Reviewed in the United States on June 2, 2026
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Verified Purchase
CH
Charlottesville, US
★★★★★ 5
Bought again but note the material was different .
Fit Type: 33" Inseam, Size: Medium, Color: White
Love these pants . Good quality. Good material and made well. Bought a second pair but they are lighter weight material which is nice for the summer. Will buy again. First heavier white material did not shrink. Not sure about the most recent material as I haven’t washed them yet. Size true to fit
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Reviewed in the United States on May 30, 2026
A
Verified Purchase
Amazon Customer
Grantham, US
★★★★★ 5
Good length, nice and comfy!
Fit Type: 33" Inseam, Size: Medium, Color: Army Green
Update after wearing on international trip: I still love these pants, but something about the high waist doesn’t look great on me if I wear a shorter length or cropped top (usually what I wear with high waisted pants). The waistband is too wide, and it looks unflattering. I may try to get it altered (again) to have a thinner waistband, but not eager to spend any more on these than I already have. 😭 Original review: I love these pants….I really wanted a natural fiber pant that wasn’t ankle length (I’m 5’8”)! I do NOT like that so so so many pants (from some of my favorite name brands but especially here on Amazon also) are “high waters”. These are a tad long at 33” (they didn’t have the 31” in size M in the color I wanted), but I will get them hemmed. I am also long waisted and don’t usually like wide waistbands, but this waistband doesn’t bother me, and they look great on. They did not seem to shrink after washing, and I even put them in the dryer on low for about 10 minutes (I wasn’t brave enough to go longer), and they did not shrink much. I was hoping they might shrink a tad in length. They must run a tad large, since I am a bit heavy right now, but they aren’t too tight (like so much of my wardrobe is at the moment). They are very comfortable, and I’m glad to have some pants to wear when I travel.
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Reviewed in the United States on December 23, 2025

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