Free shipping on all orders over $249

Flex Fuel E-Tune (Accessport) – 2015-2021 WRX

Flex Fuel E-Tune (Accessport) – 2015-2021 WRX

(1 customer review)


A Cobb NexGen or equivalent kit and upgraded in tank fuel pump are required for flex fuel.

Once purchased we will send you a confirmation email with a link to our online pre-tune form. With the pre-tune form we make sure you have all the correct modifications to meet your power goals.

Once filled out we will email you to get the E-Tuning process started.


By purchasing this product, you acknowledge that this is a digital file sent via email, so there are no refunds and no warranties. You have also read How E-Tunes Work and have gone over the Pre-Tune Checklist.



Check out our Mods Guide to see dyno graphs of power outputs and for a good mod path for future modifications.

Pump Gas Typical Gains

  • 270-300+ hp to the wheels!
  • +65 hp (36%) increase in horsepower over stock
  • +50 ft/lbs (24%) increase in torque over stock

Ethanol (E60) Typical Gains

  • 350+ hp to the wheels!
  • +120 hp (67%) increase in horsepower over stock
  • +80 ft/lbs (38%) increase in torque over stock

Check out our Ethanol Calculator for help blending your fuels (pump gas and E85) when fueling your car at the gas station.

All of our E-Tunes utilize the latest Cobb Custom Features (CCF) maps to give you the best driving experience. Some of the features we set up on all tunes are:

  • Remove the stock “rev hang”
  • Full time closed loop fuelingWe tune every car with full-time closed loop fueling. That means the front O2 sensor controls the AFR under full throttle ensuring the AFR is always spot on.
  • Smoother boost for more linear power delivery
  • Boost by GearAll MT tunes have boost by gear. This helps your car hit close to boost target in all gears.
  • High Gear Over-Boost ProtectionWe employ over-boost protection in 4th-6th to limit boost below defined rpms. An example is if someone goes WOT in too high a gear at too low an rpm, boost is limited to wastegate pressure to keep engine loads low and reduce the risk of engine damage.
  • User adjustable Launch Control and Flat Foot Shift

If you have any questions about E-Tuning you can call us at 763-316-5882 or email us at


Pre Tune Checklist

Tuning DOES NOT fix mechanical issues or misfires. Tuning is for vehicles that are already in good running condition.  Tuning is for making aftermarket parts work properly together.


Fuel Related Pre Tune Checks

  • Do you have the fuel octane you want to be tuned on in your tank? – It is critical you have the fuel you want to be tuned on in your fuel tank when you come in for the tune. We can only tune your car for the fuel that is in the fuel tank. If you tune on 93 octane you will make more hp but you can damage your engine if you boost with 91 or 92 octane in your vehicle. If you want to be able to run 91, 92, or 93 then you will want to tune your vehicle with 91 octane in it.
  • Do you have nonoxygenated 91, a.k.a. no ethanol 91, ethanol-free 91 in your fuel tank? – We do NOT  recommend running 91 non oxy or non ethanol fuel (see images below for examples). We have found turbocharged Subaru’s do not like this fuel and it acts like a much lower octane in real life testing. We will tune your car on that fuel and you will make substantially less hp. If you decide to come back with a better fuel you will have to pay for a tune adjustment (e-tune hourly rate). If you only have access to 91 non oxy, we have found an aftermarket intercooler can help keep the power where it’s supposed to be.
    • We have found that most Kwik trips in Minnesota have nonoxygenated 91 and the pump is not always labeled non oxy, so we recommend staying away from them for pump gas.
  • Is your MAF (mass air flow) sensor dirty?– We recommend cleaning your MAF with MAF cleaner before your tune. If we tune your car with a dirty or bad MAF, if you ever decide to clean or replace it your tune will likely be off and you will need a new tune (we DO NOT recommend using aftermarket MAF sensors, even if it’s the same brand as the OEM they can read differently than stock and typically don’t last as long. Always buy OEM from the dealer)
  • Does your front O2 sensor operate correctly?– If your front O2 sensor is not working we can NOT tune your car. (we DO NOT recommend using aftermarket O2 sensors, even if it’s the same brand as the OEM they can read differently than stock and typically don’t last as long. Always buy OEM from the dealer)
  • Check or replace your fuel filter
  • Check/set fuel pressure. (If you installed an aftermarket adjustable fuel pressure regulator you need to set it. All aftermarket fuel injectors are flow rated at 43.5psi. That is the recommended base pressure for you to use. Always set base pressure with a warm engine and the vacuum line disconnected from the fpr and plugged.)
    • Stock Fuel Pressure from the Manufacture
    • All turbo EJ Subarus- 41-46psi
    • 2015-2021 WRX- 49-58psi
    • BRZ/FRS/86- 51-72psi


non oxy vs 91

Boost Related Pre Tune Checks

  • Verify no boost/vacuum leaks. If you recently installed a front mount intercooler / piping or had your engine apart a boost/vacuum leak test is a must!
  • Clean or replace your air filter
  • If tuning 02-14 WRX/04-07 STI models for over 22 PSI an aftermarket MAP (manifold absolute pressure) sensor is required
  • If tuning 08-2021 STI models for over 26 PSI an aftermarket MAP (manifold absolute pressure) sensor is required
  • If tuning EVO X models for over 30-32 PSI an aftermarket MAP (manifold absolute pressure) sensor is required
  • If tuning EVO 8 / 9 models with Speed Density an aftermarket MAP (manifold absolute pressure) sensor is required
  • If tuning BRZ/FRS/86 with added forced induction an aftermarket MAP (manifold absolute pressure) sensor is required


Engine Mechanical Related Pre Tune Checks

  • Perform a compression test– knowing the health of your engine before the dyno tune is critical to make sure you get the most out of your tune. Compression should be within 10% on all cylinders.
  • How many miles are on your spark plugs? If you don’t know the history of your spark plugs please replace them beforehand. 
  • We CANNOT tune with misfires
  • Do you have any oil, coolant, or transmission fluid leaks.– All leaks should be addressed before your e-tune. 
  • When is the last time you changed your engine oil?–  We recommend having fresh engine oil to help prevent engine failure at higher RPMs. Mobil 1 and Royal Purple are NOT recommended in turbo Subaru engines.
    • For the EJ engines, we recommend Rotell T6 5w40, Motul 8100 X-cess 5w40, Motul 6100 Synergie 10w40 (good for E85), or Motul 300v 5w40, 15w50.
    • For the FA’s we recommend Motul 8100 X-clean efe 5w30.
  • Does your car overheat at idle or under load?– Your cooling system should be properly burped and be able to keep your car form overheating at idle or when driving.
  • Do you have any exhaust leaks?– exhaust leaks can cause the AFR sensor to read inaccurate and potentially cause the tune to be incorrect.
  • Do you have any check engine lights on?– Your car should NOT have any check engine lights on when you come in for the tune.
  • Walnut blasting is recommended every 25,000-50,000 miles (2015-2021 WRX and 2014-2018 FXT only)


Vehicle General Maintenance and readiness to strap on the Dyno Pre Tune Checks

  • Are your tires properly inflated?– Make sure tires are fully inflated to the correct pressure (30-40psi recommend) 
  • Does your car drive strait down the road?– Your car should have a proper wheel alignment. 
  • Is your clutch up to the task of holding more power?– Make sure your clutch is not slipping and able to handle the torque for the upgraded mods
  • Does your battery and charging system operate correctly?If the battery dies while flashing a tune on the car it can brick the ECU, leaving you with a car that will not run. If your car has to be jumped every time to start it needs a new battery in order to be tuned.
  • How old are your Transmission, Rear Diff, and Transfer Case(where applicable) fluids?– make sure these fluids are fresh and full . 


How E-Tunes Work

What is a E-Tune

The short answer is we provide you a tune via email. The long answer includes you getting to have some fun in your car. Have you ever wondered how E-Tunes work? The following information will provide you will all the ins and outs of how E-Tunes work. With this knowledge, you can confidently purchase an E-tune and start getting more smiles per gallon. Once you purchase an E-Tune we will email you your first revision along with detailed instructions to complete the E-Tune. The instructions include everything from loading the tune to your Accessport to performing data logs. All you have to do is send us data logs, we then review them and send you a new revision. Rinse and repeat until the tune is complete.

E-Tuning is a great way to get a custom tune without getting on a dyno. A dyno simulates road load. Since it does that we can accomplish a tune without putting your car on the dyno with the logs you send us. E-Tuning does not replace dyno tuning and is not a less expensive option than dyno tuning. A dyno tune will always get you the most power and the best driving tune. With that said an E-Tune will still get you a well-performing and reliable tune. If you don’t live near a dyno facility an E-Tune is a great choice.

Running the Cobb OTS maps can be a great option for some people, the only downfall is they require Cobb only parts. If you have/want to run different brand parts or once you are modified beyond their staged tune specifications you need a custom tune. Since all of our E-Tunes are custom to each car, we can get you a smooth running and well performing tune for your exact mods. We have years of experience dyno tuning the 2015+ WRX and know exactly what to do when tuning to give you the best driving car.

How E-Tunes Work/Typical Work Flow 

  • Purchase your E-Tune
  • Fill out the online form, received with E-Tune purchase, with mods list and we will send you the first revision.
  • Flash tune revision/perform logs
  • Email the logs to
  • We will review the logs, typically within a few hours up to 48 hours, make the needed changes to the tune and send a new revision
  • Send more logs and receive more revisions. This usually takes 5-10 revisions for a single fuel tune, more for flex fuel.
  • Once the tune is complete, we will send you a virtual dyno graph that gives you approximate horsepower and torque figures

What is needed from you to complete an E-Tune:

  • Working computer/laptop
  • Good internet connection to email logs and receive revisions
  • Good running car with no mechanical issues
  • A good flat section of road for the WOT (wide open throttle) portion of the tune. This is best so all the pulls have similar loads on the engine

Things to understand about E-Tuning

Tuning DOES NOT fix mechanical issues or misfires. Tuning is designed for vehicles that are already in good running condition and designed to make aftermarket parts work properly together. If you are booking a tune because your car is running poorly that will need to be addressed before we can start the tuning process. Check out our Pre-Tune Checklist for more information.

If we run into mechanical issues while tuning, the tuning will be paused until mechanical issues are fixed. We tune these cars all day on the dyno and know when parts are performing as expected. 9 times out of 10 when we have issues, it’s a mechanical issue and not related to the tune at all. If after a few revisions the car isn’t responding as it should it will be up to you to either diagnose and repair the problem or bring the car to a reputable shop that knows how to diagnose and fix issues on these cars. We can only help you so far over the internet.

E-Tuning revisions and log reviews are done Mon-Fri 8:00 am-4:00 pm (CST). E-Tuning is not available on the weekends. You are welcome to perform your logs in the evenings or weekends and email them to us. We will review them as soon as possible during our open hours and send new revisions. Depending on the time of year and how busy we are, you may receive your tune revisions in a few hours up to 48 hours after the data logs are sent.

Emissions Compliance Up-Dates:

Times are changing. To keep the aftermarket performance industry alive and following Cobb’s “Project Green Speed”, we can not disable any check engine lights while Tuning. That means we cant tune your car if you have TGV or EGR Deletes. If you have any questions or are unsure if we can tune your car, please contact us at

We CAN still tune E85, Upgraded Turbos, Fuel Injectors, Fuel Pumps, Intercoolers and more. These updates really only remove the ability to turn off check engine lights and flex fuel. We already off a new version of flex fuel, that works with the latest Cobb Green Speed updates, for the 2015+ WRX and more models are soon to follow! Check our Blog for the latest updates.

Cobb Tuning Project Green Speed Updates.

Project Green Speed 3/31/2021

Project Green Speed update 1/31/2022

Project Green Speed update 3/16/2022

Project Green Speed update 4/18/2022 – Removal of Flex Fuel & DTC suppression

Project Green Speed FAQ for 4/18/2022 update


1 review for Flex Fuel E-Tune (Accessport) – 2015-2021 WRX

  1. Alvin Phan

    Cannot say enough kind words for JM Auto and Devin who tuned my car. Great communication and definitely is detail oriented when it comes to making sure the tune runs well. I went with a flex fuel tune for my 2017 WRX and cannot be more happy! From start to finish, the communication and knowledge was top notch. Highly recommend!

Only logged in customers who have purchased this product may leave a review.