NexGen Flex Fuel is here.  Today we are extremely excited to release NexGen Flex Fuel support for our Subaru platform here at COBB, covering USDM 2008-2021 WRX STI.  This release consists of an all new NexGen Flex Fuel Ethanol Content Sensor Kit, Stage Power Packages with supporting Off The Shelf Maps, and support in Accesstuner Pro for custom tuning.  COBB NexGen Stage 2 + Flex Fuel Stage Power Packages and Off The Shelf Maps have undergone and passed third party emissions / reasonable basis testing and are currently available in 49 states as we continue to seek a CARB EO.

NexGen Flex Fuel Components

The below NexGen Flex Fuel components are compatible with all supported 2008-2014 STIs.

At the heart of NexGen Flex Fuel is our all new module and harness solution.  This module takes signal from the ethanol content sensor placed in your car’s fuel line and converts it into something that the ECU can then comprehend and utilize to make calibration changes on the fly to account for any change in ethanol concentration.

NexGen Stage 2  to Nexgen Stage 2+ Flex Fuel Upgrade Package

This upgrade package is all that is necessary for those who are already taking advantage of our 50-State Legal NexGen Stage 2 Power Package.  With the supporting fuel system already handled within that package, all that is needed in order utilize our supporting Off The Shelf Map are the two sensor kits below for ethanol content and fuel pressure.

NexGen Flex Fuel Ethanol Sensor Kit

Fuel Pressure Sensor Kit

NexGen Flex Fuel Module + Harness Kit

For those who were utilizing our previous Flex Fuel components, this upgrade package is all you would need in order to move into the NexGen product line.  Your existing COBB fuel rails, lines, and ethanol content sensor configuration can be retained.  This kit includes the bare necessities; an all new NexGen module and plug-and-play harness.

2008-2014 STI Flex Fuel Packages

NexGen Stage 2 + Flex Fuel Power Package

A new NexGen Stage 2 + Flex Fuel Power Package is now available for 2008-2014 STIs.  At the core of this package is our 50-State Legal NexGen Stage 2 Power Package.  The airflow and fuel system upgrades in that package in addition to the NexGen Flex Fuel hardware are required in order to take advantage of our SEMA Certified NexGen Stage 2 + Flex Fuel Off The Shelf (OTS) Map.

Stage 1 to NexGen Stage 2 + Flex Fuel Power Package Upgrade

Stage 1+ to NexGen Stage2 + Flex Fuel Power Package Upgrade

For customers who may already have an Accessport or Accessport and Intake, they can choose one of our “upgrade” power packages, which include all of the fuel system upgrades, turbo inlet hose, spark plugs, and NexGen Flex Fuel components.

Power Gains

Supporting COBB Off The Shelf Maps can be downloaded from the Maps section of our website after configuring your applicable vehicle.  For additional information on COBB OTS Maps, see the Map Notes Page.

Vehicles utilizing the complete NexGen Stage 2 + Flex Fuel power package and accompanying OTS Map can expect to see gains as displayed below.

2015-2021 STI Flex Fuel Packages

Introducing NexGen Stage 2 + Flex Fuel Power Packages!  These power packages are based upon our 50-state legal NexGen Stage 2 Power Packages, simply adding NexGen Flex Fuel into the mix by way of our all new ethanol content sensor kit and fuel pressure sensor kit.  For 2015-2021 STI there are three flavors of the package, the difference being which intake is included.  All three of these Power Packages are supported by COBB Off The Shelf Maps.

NexGen Stage 2 + Flex Fuel Power Package 2015-2018 STI (SF Intake)

NexGen Stage 2 + Flex Fuel Power Package 2019-2021 STI, 2018 STI Type RA (SF Intake)

NexGen Stage 2 + Flex Fuel Redline Carbon Fiber Power Package 2015-2021 STI, 2018 STI Type RA

Power Package Upgrade Kits

If you are already utilizing a COBB Stage Power Package and want to move into a NexGen Flex Fuel Power Package, we have you covered!  The packages below are available for vehicles that are currently in a Stage 1 or Stage 1+ (intake) configuration.

From current Stage 1 (Accessport re-used)

Stage 1 to NexGen Stage 2 + Flex Fuel 2015-2018 STI Power Package Upgrade

Stage 1 to NexGen Stage 2 + Flex Fuel 2019-2021 STI, 2018 STI Type RA Power Package Upgrade

Stage 1 to NexGen Stage 2 + Flex Fuel w/ Redline Carbon Fiber Intake Power Package Upgrade

From current Stage 1 + Intake (Accessport + Intake re-used)

Stage 1 + to NexGen Stage 2 + Flex Fuel Power Package Upgrade

Off The Shelf Maps and Power Gains

These map files are only available to be downloaded from the Maps section of the COBB website.  Download Flex Fuel Off The Shelf Maps HERE.

NexGen Stage2 1050x + Flex 91

NexGen Stage2 1050x + Flex 91 HWG

NexGen Stage2 1050x + Flex 91 LWG

NexGen Stage2 1050x + Flex 93

NexGen Stage2 1050x + Flex 93 HWG

NexGen Stage2 1050x + Flex 93 LWG

NexGen Stage2 1050x + Flex ACN91

NexGen Stage2 1050x + Flex ACN91 HWG

NexGen Stage2 1050x + Flex ACN91 LWG

This dyno graph shows the ranges of horsepower and torque that you can expect to experience when using the COBB NexGen Stage 2 + Flex Fuel Power Package and accompanying OTS map. Using 93 octane with up to E10, our development car made a peak of 307 whp and 338 wtq., exactly what you’d expect to make on a normal NexGen Stage 2 Power Package. Then, without changing a single part on the car and using the exact same tune, we bumped the ethanol percentage in the tank up to E65 where the car made a peak of 332whp and 373wtq.  With a full tank of E85, we topped out at 336whp and 379wtq!  As you can see, the majority of the gain occurred by simply getting the car to that E65-ish range and the extra 20 points of ethanol content did not produce an overwhelming difference in power.

Looking for more specifics about our Off The Shelf Maps? Head over to the Map Notes Pages linked below.

Map Notes for 2019-2021 STI, 2018 STI Type RA

Map Notes for 2015-2018 STI

These map files are only available to be downloaded from the Maps section of the COBB website.  Download Flex Fuel Off The Shelf Maps HERE.

Custom Tuning Support

Subaru Accesstuner Pro HL has also been updated to support NexGen Flex Fuel hardware.  COBB Protuners can create custom calibrations for emissions compliant vehicles that are utilizing our NexGen Flex Fuel Ethanol Sensor Kit and 5-pin Fuel Pressure Sensor Kit.

Find your preferred COBB Protuner HERE.