Cobb NexGen Flex Fuel Ethanol Sensor Kit – 2011-2014 Subaru WRX

Cobb NexGen Flex Fuel Ethanol Sensor Kit — 2011-2014 Subaru WRX

The Cobb CAN Flex Fuel Kit for the 2011-2014 Subaru WRX installs the CAN-based ethanol content sensor and fuel pressure sensor in the fuel delivery system, enabling the Cobb CAN Flex Fuel OTS maps to dynamically adjust the Accessport calibration based on measured fuel composition. Requires an Accessport V3 with CAN Flex Fuel OTS maps loaded.

DETAILS

• Platform: 2011-2014 Subaru WRX
• CAN-based ethanol sensor: measures actual ethanol content in real time
• Enables Accessport CAN Flex Fuel OTS maps for dynamic calibration
• Works with E10 through E85 and any blend in between
• Requires Accessport V3 with CAN Flex Fuel map capability

How Flex Fuel Works on Subaru

Cobb’s CAN Flex Fuel system uses an ethanol content sensor installed in the fuel line to measure the actual ethanol percentage of whatever fuel is in the tank at any given time — whether it is straight pump E85 (typically 70-85% ethanol), E30, E40, any custom blend, or straight 93-octane gasoline. This measurement is sent to the Accessport via the CAN bus, and the Accessport ECU map adjusts fueling, ignition timing, and boost targets automatically based on the real ethanol content — not based on which OTS map slot the driver selects, but based on what the sensor actually reads. This means an owner can run any blend of ethanol and gasoline without switching maps or worrying about whether the current map matches the fuel. The ECU dynamically adjusts for the fuel being used.

CAN System, OTS Maps, and Ethanol Blends

Ethanol provides two performance advantages over gasoline that the flex fuel system exploits. First, ethanol has a much higher effective octane rating than pump gasoline — this allows more aggressive ignition timing advance without risk of detonation. Second, ethanol has a high latent heat of vaporization — it absorbs a significant amount of heat when it evaporates in the intake manifold and combustion chamber, cooling the intake charge and further reducing knock tendency. Together, these properties allow the flex fuel OTS maps to target meaningfully higher boost levels and more aggressive timing than the equivalent 93-octane gasoline maps. The real-world result is a substantial power increase on E30 or higher ethanol blends over what the same engine produces on 93 octane. The flex fuel system makes this power increase accessible without requiring the driver to maintain a specific fuel blend or manually switch calibrations — the system adapts automatically to whatever is in the tank.

What’s in the Box

• CAN flex fuel ethanol sensor
• Fuel line fittings and hardware
• Installation instructions

Why Choose Cobb Tuning

Cobb Tuning has been developing performance software and hardware for turbocharged enthusiast vehicles since 1999. Founded in Austin, Texas, Cobb built its reputation on the Accessport and expanded into a full catalog of hardware engineered to complement it. Every OTS map is developed in-house on real vehicles, and every hardware product is validated as part of a complete system — not sourced and sold in isolation. That integrated approach is why Cobb produces consistent, reliable results across the builds we see every day.

The RallySport Take

The Cobb CAN Flex Fuel system for the 2011-2014 Subaru WRX gives Accessport-equipped owners the ability to run any ethanol blend — from 93 octane through E30, E50, and full E85 — with the Accessport automatically adjusting the calibration for the measured fuel composition. The ethanol sensor reads the blend in real time, and the CAN bus communicates that reading to the Accessport ECU map continuously. The driver does not need to know or track the exact ethanol percentage — the system handles it. Requires an Accessport V3 with the appropriate CAN Flex Fuel OTS maps for the platform.

Fitment

Year	Make	Model	Notes
2011-2014	Subaru	WRX	EJ255/FA20DIT — requires Accessport with CAN FF maps