• Brian Keene

Stock ECU vs Standalone ECU in your Subaru

Updated: Jan 7

Haltech Elite ECU Custom Wiring

UPDATE AS OF JANUARY 2021. Unfortunately iWire is no longer building harnesses for standalone ECUs to focus on stock ECU applications. Below is still good information if you are looking into this subject.

When starting any Subaru powered project one of the first questions in your planning should be, "What ECU should I use?" The ECU or Engine Control Unit functions as the brain for your engine. The ECU optimizes the engine performance based on information from a wide variety sensors as well as requests from the driver. With such a complex job, it is critically important to start your project with the ECU.

iWire recommends using the Stock ECU in your project whenever possible. Subaru, more specifically the ECU manufacturer for most Japanese manufacturers Denso, has spent a lot of time and money (more than any aftermarket company could dream of) on developing a product that will work under just about any situation and keep the engine running happily and reliably which is why we recommend it. However, it is not a possibility for all swaps. Sometimes the OEM ECU isn't an option because it is not compatible with the car that it is going into. While in other cases there are certain features that only a standalone can provide. Read below to see which Subaru swaps most commonly need a standalone ECU.

Subaru Swaps that Can Not Use the Stock ECU:

  • 6 Cylinder (H6) swaps

  • CANBUS engine into Non CANBUS car (example: 2009 engine into 1993 chassis)

  • ​Non tunable from factory cars (example: Early JDM Models or Non Turbo Applications)

  • Non CANBUS engine into CANBUS car (example: 2002 WRX into 2010 Chassis)

If you are not sure if your swap needs a standalone ECU - Contact Us!

Which Standalone ECUs Does iWire Recommend?

  • Haltech

  • AEM

  • Emtron

  • Adaptronic

  • Motec

We use these brands because not only do they make quality products with a user friendly interface and have good customer support. We stake our reputation on every build we do so we only use reliable ECU's.


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