Subaru Fuel Rail and Injector Upgrade Options
By DeatschWerks | Published: 2026-10-20
Category: Buying Guides
Choose the right DeatschWerks fuel rail and injector kit for your Subaru. Compare 750cc to 2200cc injectors and top feed vs conversion kits.
Quick answer
For a bolt-on fuel rail upgrade on 2002-2014 WRX or 2007-2015 STI, choose a DeatschWerks top feed kit with 750cc or 1200cc injectors. For 2004-2006 STI or Legacy GT that came with side feed injectors, pick a conversion kit with 1500cc or 2200cc injectors depending on your power target.
Top feed vs side feed: know your base setup
Subaru engines use two different injector styles depending on the model year. 2002-2014 WRX and 2007-2015 STI came with top feed injectors from the factory. 2004-2006 STI and Legacy GT used side feed injectors.
If your car is a side feed model, you cannot simply swap injectors. You need a conversion fuel rail kit that replaces the entire fuel rail and injector assembly to switch to a top feed configuration. DeatschWerks offers dedicated conversion kits for these years.
Top feed kits are a direct upgrade for cars that already have top feed rails. They include new rails and injectors that bolt in without modifying the fuel system layout.
Injector size and power goals
The injector flow rate (cc/min) determines how much fuel the engine can deliver. Larger injectors support higher horsepower but may sacrifice idle quality if oversized for your setup.
750cc injectors are a good match for stage 2 or mild turbo upgrades on a WRX or STI, supporting roughly 350-400 whp on pump gas. 1200cc injectors are common for larger turbos and E85 builds, supporting 450-550 whp.
1500cc and 2200cc injectors are intended for high-horsepower builds, often with aftermarket engine management. The 1500cc kit is a popular choice for 2004-2006 STI owners targeting 500+ whp. The 2200cc kit is for serious race setups exceeding 600 whp.
Conversion kit considerations
DeatschWerks conversion kits for 2004-2006 STI and Legacy GT include everything needed to switch from side feed to top feed: new fuel rails, injectors, and necessary hardware. This eliminates the need for adapters or custom fabrication.
The 1500cc and 2200cc conversion kits use the same rail design, so the choice comes down to injector flow. If you are unsure which size you need, start with the 1500cc kit—it offers headroom for most built engines without the idle trade-offs of 2200cc injectors.
Decision rules
- Identify your injector type: Check your Subaru model year: 2002-2014 WRX and 2007-2015 STI use top feed. 2004-2006 STI and Legacy GT use side feed. If you have side feed, you need a conversion kit, not a standard upgrade kit.
- Match injector size to power target: 750cc for up to ~400 whp, 1200cc for 450-550 whp, 1500cc for 500+ whp, 2200cc for 600+ whp. Oversizing can hurt idle quality. Choose the smallest injector that meets your power goal for best drivability.
- Choose between upgrade and conversion: If your car already has top feed, pick a top feed upgrade kit. If it has side feed, pick a conversion kit that matches your injector size. Conversion kits are model-specific—verify fitment for 2004-2006 STI or Legacy GT only.
Product facts
- Subaru upgrade fuel rails and 1200cc injectors: Subaru top feed fuel rail upgrade kit with 1200cc injectors for MPFI WRX 2002-2014, STI 2007-2015, and Legacy GT 2007-2012 This kit is a direct upgrade for top feed cars, giving you 1200cc flow without changing the fuel system layout.
Subaru upgrade fuel rails and 1200cc injectors - Subaru conversion fuel rails and 1500cc injectors: DeatschWerks conversion kit replaces side feed components with top feed fuel rails and 1500cc injectors for 2004-2006 Subaru STI and Legacy GT If you own a 2004-2006 STI with side feed injectors, this is the complete solution to upgrade to a top feed system with high flow capacity.
Subaru conversion fuel rails and 1500cc injectors
Fit guidance
Best for
- Owners of 2002-2014 WRX or 2007-2015 STI wanting a direct top feed upgrade with 750cc or 1200cc injectors
- Owners of 2004-2006 STI or Legacy GT needing a side feed to top feed conversion with 1500cc or 2200cc injectors
Not for
- Cars outside the listed model years without adapter kits or custom fabrication
- Mild street builds that do not need aftermarket engine management to control larger injectors
