SKU: B315250 | UPC: 700424676378
COBB Adjustable Fuel Pressure Regulator Kit 2008-2021 Subaru STI (w/ COBB Fuel Rails)
The COBB 315250 Adjustable Fuel Pressure Regulator Kit delivers precise fuel control for 2008-2021 Subaru WRX STI equipped with COBB Top-Feed Fuel Rails (315400 or 315500). Featuring a genuine Aeromotive 13129 regulator with 30-70 psi base pressure adjustment and true 1:1 manifold reference, it supports E85, flex fuel setups, larger injectors, and high-horsepower EJ257 builds up to 1000+ hp. Pre-assembled with CNC bracket and -6 AN line for straightforward installation.
Key Features
- Aeromotive 13129 Regulator: Fully adjustable 30-70 psi with 1:1 rising rate for accurate fuel delivery across all RPM and boost levels
- CNC Billet Firewall Bracket: Black anodized 6061 aluminum for secure, low-profile mounting on STI firewall
- Pre-Assembled -6 AN PTFE Line: Stainless braided with crimped fittings for reliable, leak-free fuel flow
- Designed for COBB Fuel Rails: Required companion to 315400 (08-14 STI) or 315500 (15-21 STI) top-feed rails
- Made in USA: Lifetime warranty against defects with COBB engineering standards
Product Notes
- Required for COBB Fuel Rails as factory regulator location is deleted
- Not compatible with OEM fuel rails (use COBB 315200 FPR for stock rails)
- In stock and ships in official COBB retail box
Installation Notes
- Professional installation recommended.
- 45-60 minute install: mount bracket to firewall, route pre-assembled line from rail to regulator
- Accessport tuning required after pressure adjustment; includes adjustment tool
This Part Fits
| Year | Make | Model | Submodel |
|---|---|---|---|
| 2008-2021 | Subaru | WRX STI | – |
Why Choose COBB Tuning?
- 1 name in Subaru performance for over 20 years
- Engineered and manufactured in the USA
- Proven on every 600-1000+ hp EJ257 build worldwide
Frequently Asked Questions
- Q: Do I need this with COBB fuel rails?
A: Yes, required for 2008-2021 STI as COBB top-feed rails (315400/315500) delete factory regulator location. - Q: Does it work on 2015+ STI?
A: Yes, fits all 2008-2021 WRX STI with EJ257 engine and COBB rails; not for FA20 WRX. - Q: How do I adjust pressure?
A: Fully adjustable on the fly with included tool; set 30-70 psi base for E85 or power builds, then tune with Accessport.
Shipping & Handling
- Method: UPS/FedEx Ground
- Availability: In stock – ships same or next business day
- Packaging: Official COBB retail box (10″ x 8″ x 4″)
- Weight: 2.0 lbs
