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
COBB
COBB Tuning parts for turbocharged performance platforms are stocked at Black Ops Auto Works. Shop the Accessport ECU programmer, cold air intakes, cat back exhaust systems, and supporting hardware engineered for Subaru WRX and STI, Ford Focus ST and RS, Ford F-150 EcoBoost, Mazdaspeed3 and 6, Nissan GT-R, Porsche, BMW, and Volkswagen platforms. Every product is filterable by year, make, model, and trim so the correct part ships the first time. Black Ops Auto Works carries 372 COBB SKUs across tuning, intake, and exhaust categories. What This Brand Covers COBB Tuning built its reputation on the Accessport, one of the most widely used ECU flash tools in the aftermarket, and has expanded into intakes, exhausts, downpipes, and supporting hardware for a range of turbocharged platforms. The catalog centers on a defined group of import and Euro performance vehicles rather than a single brand family. Brand Focus COBB Tuning parts are engineered primarily for Subaru, Ford, Mazda, Nissan...
View COBB Products
Engine
Engine parts and engine bay upgrades for Dodge, Jeep, RAM, Chrysler, Chevrolet, Ford, Toyota, Nissan, Subaru, and Honda vehicles are stocked at Black Ops Auto Works. Shop oil catch cans, supercharger pulleys, thermostats, radiators, cooling parts, throttle bodies, intake manifolds, headers, ignition coils, spark plugs, sensors, gaskets, fuel pumps, valve covers, engine covers, billet cap covers, and full engine bay dress-up parts for HEMI, Hellcat, Trackhawk, Redeye, Demon, Scat Pack, RAM TRX, LS, LT, Coyote, EcoBoost, K-Series, and 2JZ builds. Every product is filterable by year, make, model, trim, engine, and drivetrain so the correct part ships the first time. Black Ops Auto Works carries 14,298 engine SKUs across performance, cooling, oil control, ignition, and appearance categories. What This Category Covers The Engine collection combines OEM-replacement engine service parts with performance aftermarket upgrades for supercharged, turbocharged, and naturally aspirated builds...
View Engine Products
Fuel Delivery
Fuel delivery parts for gas and diesel trucks, muscle cars, and import performance builds are stocked at Black Ops Auto Works. Shop fuel pumps, fuel pump modules, fuel rails, pressure regulators, fuel filters, fuel tanks, carburetors, flex fuel kits and sensors, fuel caps, and surge tanks for Ram Cummins, Ford Powerstroke, Dodge Charger and Challenger, Jeep, Chevrolet, Honda, Nissan, and Infiniti platforms. Every product is filterable by year, make, model, trim, engine, and drivetrain so the correct part ships the first time. Black Ops Auto Works carries 1,874 fuel delivery SKUs across pumps, hardware, and tank categories. What This Category Covers Fuel delivery parts move fuel from the tank to the engine at the pressure and volume the injectors or carburetor need. This collection spans in-tank and external fuel pumps, pump modules and hangers, fuel pressure regulators, fuel rails, filters, tanks, carburetors, flex fuel conversion kits, and the caps and misc components that comp...
View Fuel Delivery Products
Fuel Pressure Regulators
Fuel pressure regulators and fuel system control parts for LS, Coyote, Hemi, K-series, 2JZ, EJ and diesel builds are stocked at Black Ops Auto Works. Shop adjustable EFI regulators, rising-rate FPRs, return-style regulators, carburetor regulators, regulator and filter combinations, springs, gauges and fittings for naturally aspirated, boosted and E85-ready fuel systems. Every product is filterable by year, make, model, trim, engine, and drivetrain so the correct part ships the first time. Black Ops Auto Works carries 156 fuel pressure regulator SKUs across return systems, boost-referenced setups, carbureted applications, direct-mount EFI hardware and service parts. Fuel Pressure Regulator Basics Control pressure at the rail or carburetor A fuel pressure regulator controls fuel pressure delivered to injectors or a carburetor. In a return-style EFI system, excess fuel returns to the tank while the regulator maintains the chosen base pressure at the rail. Choose a regulator around ...
View Fuel Pressure Regulators Products


