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Power Pack Flex Fuel Add-On (08-17 STI, 08-14 WRX)


  • $ 1,150.00

This is an add-on for our Stage 2 and Stage 2 Plus Power Packs that will allow you to seamlessly switch between pump gas and ethanol based fuels such as E85. E85 can be found at pumps all over the country and provides a cheap alternative to race gas. Depending on setup, simply switching to E85 with an appropriate tune will increase power by 50-100hp and as much as 130ft-lbs of torque as compared to pump gas alone. With this setup, you'll be able to pump regular gas, E85, or any mix of the two into your tank and the ECU calibration will automatically adjust to any ethanol content in the tank.

Running E85 and turning your Subaru into a true Flex Fuel vehicle requires a few key modifications. 


-- First we need to increase the fueling capacity. E85 requires approximately 30-40% more fuel flow than regular pump gas, so we need to increase the injector size to support this. For this, we go with the widely trusted injector company Injector Dynamics and their incredible ID1050x Injectors. These injectors offer unrivaled quality and consistency, allowing us to offer stock like idle and drivability while delivering enough fuel for up to 450hp! We also include plug and play adapters for a simple install without cutting wires. 

-- Now that we have enough fuel supply, we need a sensor that will detect the concentration of ethanol in the fuel and send that data to the ECU. For this purpose, we go with Cobb's Flex Fuel Kit. This is a complete plug and play solution enabling users to convert their supported Subaru WRX or STI to a Flex Fuel configuration. This is the easiest to use and most sophisticated Flex Fuel kit on the market. Utilizing OEM fuel and electronic connectors, the Ethanol Sensor Kit measures the ethanol content of fuel being fed to the motor. That data is then converted into a signal that the ECU can use for adjusting calibrations and to be displayed on a custom Accessport monitor.


** Please note that flex fuel setups generally require custom tuning. We offer local and remote tuning services for these purposes. Please contact us for additional information.

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