SUBARU NEXGEN FLEX FUEL ETHANOL SENSOR KIT STI 2008-2021

Part Details:

The COBB NexGen Flex Fuel Ethanol Sensor Kit is the core component required to add true flex fuel capability to supported Subaru STI models from 2008–2021. This plug-and-play solution provides precise ethanol content data to the ECU, allowing properly calibrated vehicles to automatically adapt to changing fuel blends, including ethanol-based fuels.

Designed for straightforward installation and long-term reliability, the kit combines OEM-quality sensors with vehicle-specific hardware and a dedicated NexGen control module. Once installed, ethanol content data is processed by the NexGen module and delivered directly to the ECU for use with Accessport-based NexGen Flex Fuel calibrations.

How It Works

Fuel is routed through an ethanol content sensor mounted on a custom powder-coated aluminum bracket. The sensor continuously measures ethanol percentage before the data is processed by the NexGen Flex Fuel module. This information allows the engine management system to dynamically adjust fueling strategies based on the detected fuel blend—eliminating the need to manually change maps when switching fuels.

Key Features

• Designed specifically for Subaru STI models from 2008–2021

• OEM-quality ethanol content sensor for accurate and consistent readings

• NexGen Flex Fuel Module to process and transmit ethanol data to the ECU

• Plug-and-play wiring harness using OE-style connectors for clean installation

• Pre-configured fuel line integration, compatible with COBB fuel system components

• Billet adapter included for seamless connection with COBB fuel rail line kits

• Engineered for reliability, drivability, and tuner-friendly data accuracy

Why Add a NexGen Ethanol Sensor Kit?

Ethanol blends can unlock significant performance potential, but only when the ECU has accurate fuel composition data. This kit provides the foundation for safe and effective flex fuel tuning by ensuring the engine management system always knows what fuel is being used. It’s an essential upgrade for STI owners planning to run ethanol blends or seeking greater flexibility from their fuel system.

Recommended Supporting Fuel Components

• Fuel Injectors – higher ethanol content often requires increased fuel flow to maintain proper air-fuel ratios.
• Fuel Pumps – support the additional fuel volume needed for ethanol and higher power levels.
• Fuel Pressure Regulators – help maintain consistent fuel pressure across varying ethanol blends.
• Fuel Delivery Components – explore supporting fuel system parts designed to work together.

Learn more about COBB Tuning performance solutions and supporting components