Supported Vehicles:

• Model year 2008-2014 STI (North American, ADM Spec)

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Fuel Requirements:

Each map lists the minimum required octane. A higher octane fuel can be used safely on a map designed for lower octane. DO NOT use maps designed for higher octane with lower octane fuels. Top Tier gasoline should be used where available.

• Maps designated with "93" are for use with 93 octane fuel (98 RON) or better.

• Maps designated with "91" are for use with 91 octane fuel (95 RON) or better.

• Maps designated with “ACN91” are for use with 91 octane fuel found in Arizona, California, and Nevada or better.

These maps are designed for E10 fuel (fuel with 10% ethanol content). For those who only have access to E0 fuel (fuel with 0% ethanol) it is recommended to use the "91" octane version of the maps and datalog the car to ensure your fuel is performing to the necessary level. This is especially important for those using Canadian 94 octane E0 fuel. 

Stage 1 & 2

Hard Parts Configuration

C.A.R.B Note

The above calibrations (Stage1, Stage1+FF, NexGen Stage2 1050x) are legal for use on Emissions Controlled Vehicles in all 50 states when used in accordance with the manufacturer's application guide because it and the parts have a California Air Resources Board (CARB) Executive Order (EO) number: 

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• D-660-16

• D-660-17

• D-660-99

For additional information on CARB EO availability or the actual letter. Please check out our page CARB EO numbers for COBB Subaru Products

NexGen Stage2+Flex Fuel

NexGen Stage2+FF Gains

NexGen Stage2+Flex Fuel

• Intake Requirements:

  • COBB SF Intake+Airbox 715300

  • COBB Turbo Inlet 712450

  • COBB Throttle Body Coupler 712455

• Exhaust Requirements:

  • Stock Downpipe

  • Catback Exhaust

    • Factory Cat-Back

    • COBB Stainless Catback 515122

    • COBB Titanium Catback 515140

• Subaru Spark Plugs 2018 Type RA/2019+ STI spec. D44700

• Fuel System Upgrades

  • COBB NexGen Flex Fuel Kit (2 parts) 315260, 315670

  • COBB Fuel Pressure Sensor Kit 315650

  • COBB 1050x Injectors 312150

  • COBB Billet Fuel Rails 343150

  • COBB Fuel Line Kit 343250

  • COBB Fuel Pressure Regulator Kit 315250

  • AEM In-Tank Fuel Pump 315450

• Boost Targets

  • ACN91 (Arizona California Nevada 91Octane): ~18psi peak boost pressure tapering down as you approach the redline, +/- 1.5psi.

  • 91 Octane 95 RON Minimum: ~19psi peak boost pressure tapering down as you approach the redline, +/- 1.5psi.

  • 93 Octane 98 RON Minimum: ~19psi peak boost pressure tapering down as you approach the redline, +/- 1.5psi.

Non-Performance Maps

Monitoring Boost Levels: 

The best way to determine if you are hitting target boost is to watch the TD Boost Error parameter. This parameter is your target boost (including altitude and temperature compensations) minus your actual boost (negative values mean you are over the target by the amount while positive values mean you are under). Ideally you want this value to be between 0 and 1.0 at wide open throttle (WOT), but -1.0 to 1.0 is acceptable assuming that you don’t have any significant knock corrections. Overboosting is more likely to occur in higher gears and with colder outside temperatures, so be sure to verify boost levels during these conditions.

High Altitude: 

A quick note for those of you that live at higher altitudes. It is common for turbocharged cars at higher altitudes to run less boost pressure due to lower air pressure and air density. Your turbocharger has to work harder to compress a less dense air mass compared to the same turbocharger at sea level. This must be factored in when determining if your turbocharger is running the proper amount of boost pressure and not being pushed beyond its efficiency range. 

Example: If you live in Denver at 5280 ft and are trying to run a peak boost pressure of 15 psi, your turbocharger has to work the equivalent of making ~17.5 psi at sea level.

There are barometric compensations within the factory ECU that lower boost targets as you climb in altitude in an effort to keep the turbocharger in its optimal range. The COBB performance maps utilize these compensations and therefore, it is perfectly normal for the final boost target to be lower than what is listed for your map. 

Boost Select: 

All maps designated with “Boost Select” in the map name have a driver-controlled boost target controlled through the SI-Drive system available on the 2008+ STI. From the factory, SI-Drive will modify throttle settings and change the relation between what is done with the accelerator pedal and how the throttle blade reacts; [S#] being the most aggressive throttle settings, [S] being less aggressive, and [I] being very conservative.  What we have done is take that functionality a step further.  The “Boost Select” maps have selectable boost targets by toggling between [S#], [S], and [I].  [S#] will target the highest boost level, [S] will be a medium boost level, and [I] will be the lowest boost level (wastegate spring pressure) with conservative throttle mapping.  You can find the specific boost targets for [S#], [S], and [I] in the Map Version Notes above.

Revision Notes: