Free shipping on all orders over $199

Dyno Tuning


JM Automotive is Minnesota’s premier Subaru and Mitsubishi performance shop. We sell and install performance parts, do full engine overhauls, performance builds, and offer tuning to go with it!

Our full-time tuner Devin has been tuning Subaru’s, Mitsubishi’s and other makes for over 10 years. He has experience with both AccessPort, open source, and stand alone tuning. For more information on tuning, you can call us at 763-316-5882 or email us at

We have a lot of information about tuning and modifying your car; before doing so, please check out our Mod Guides and Why E85 is so Popular.

We are here to help!

JM Automotive is your 1 stop shop for all things performance. We can order you the right parts, install them, and get you a tune all under 1 roof. If you are looking for build advice and to purchase some parts, Contact us today to begin your build – no build is too big or too small for our experts. More information can be found by visiting our online store/parts page and filling out the form.

We offer tuning support for the following vehicles / programs:

Stock ECU

  • Cobb Accessport
    • Subaru (Flex Fuel, Speed Density)
      • 02-22 WRX, 04-21 STI, 04-18 FXT, 05-12 LGT / OBXT
    • Mitsubishi (We recommend tuning Opensource on these models)
      • 08-15 Ralliart, EVO X – GSR – MR
  • Opensource/ECU flash
    • Subaru (Carbarry – Flex Fuel / Speed Density | MerpMod – Speed Density, LC, FFS)
      • 02-14 WRX, 04-20 STI, 04-13 FXT, 05-12 LGT / OBXT
    • Mitsubishi (Tephra – Speed Density / Flex Fuel | RAX3 Patch)
      • 03-05 EVO 8, 05-07 EVO 9, 08-15 Ralliart, EVO X – GSR – MR
  • EcuTek (Flex Fuel / Forced Induction)
    • 2013-2021 BRZ/FRS/86
    • 2022+ BRZ/GR86
  • Openflash tablet
    • We do not offer tuning support via OpenFlash Tablet. EcuTek is the only method
  • Project Lambda
    • 1999-2002 Impreza / Forester, 2000-2001 Legacy

Note: A Cobb Accessport is require for tuning the following vehicles: 15+ Subaru WRXs & 14+ Subaru Forester XTs

Aftermarket / Standalone ECU

  • Emtron
  • Haltech
  • Link ECU
  • Megasquirt
  • Motorsports Electronics

If you have a different tuning software call and see if we can help you out with it.

Before modifying your vehicle, please understand the following:

  • Modifications and tuning can and most likely will void any vehicle warranty you have
  • Certain modifications and tuning are not street legal and designed for track use only
  • We are not liable for any modifications purchased from us, installed by us, or any vehicles tuned by us. Research before you modify your car and modify your car at your own risk
  • 2013-14 WRX’s have a high failure rate and have class action lawsuits against Subaru. The factory Subaru engines have some known issues, but in these years the failure rates are even higher than others, stock or modified.

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 with an Accessport if you have Air Pump, 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.

3/31/2021 Project Green Speed

1/31/2022 Project Green Speed update

3/16/2022 Project Green Speed update

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

4/18/2022 Project Green Speed FAQ update


Check out our pricing list for the most common vehicles, dual tunes, dyno rental, and more.

Pre-Tune Checklist

Check out our pre-tune checklist to make sure you and your car are ready for your scheduled tune.


Get all you need to know on modifying your 2015+ WRX or STI with first-hand experience from JM.

Ethanol Calculator

Use our ethanol calculator to easily calculate ethanol percentage in your fuel mix.

Frequently Asked Questions

Below you will some frequently asked questions relating to tuning. If you have any additional questions, feel free to reach out by calling us at (763) 316-5882 or via email.

While knock can be harmful to an engine, most knock detected by your Accessport is likely false knock. Knock, also called detonation, is when a small pocket of the air/fuel mix ignites outside of the flame front that was ignited by the spark plug. The shockwave created by this abnormal ignition creates rapid spikes of pressure in the cylinder and can cause damage if left untreated. The knock sensor is simply a microphone that is bolted to the cylinder block. The rapid spikes of cylinder pressure are what the knock sensor picks up and determines a knock event happened, the ECU then quickly makes the needed adjustments to ignition timing to try and stabilize the combustion.

Read more on our blog

When trying to diagnose driveability problems or assessing how well a new tune is working with the vehicle datalogging can be an invaluable tool.

Read more at Cobb Tuning

  1. With the Accessport installed navigate to the “gauges” menu.
  2. If it’s the first time you’ve gone to the gauge menu of the Accessport it will prompt you to ask how many monitors you want to display. The selection can be updated later in the Gauge Setup menu.
  3. From the main gauge display, you can simply hit the center button on the Accessport in order to start logging. If you haven’t pre-selected anything there are default parameters that will be logged which are typically the ones COBB Customer Support will ask you for. Note that the Accessport will show “logging” at the top of the screen and at the bottom will let you know the logging rate.
  4. In order to stop logging, you’ll need to hit the center button on the Accessport again.

Read more at Cobb Tuning

You can find the serial number to of your Accessport V3 underneath the faceplate of the device or within the software. The serial number can be found in the software by selecting “Help” at the top, then selecting “About Accessport”, lastly scroll down until you see “Serial Number Sticker”.

Read more at Cobb Tuning

Garrett Turbo describe boost creep as the following:

“Boost creep is a condition of rising boost levels past what the predetermined level has been set at. Boost creep is caused by a fully opened Wastegate(s) not being able to flow enough exhaust to bypass the housing via the Wastegate(s) itself. For example, if your boost is set to 12psi, and you go into full boost, you will see a quick rise to 12 or 13psi, but as the rpm’s increase, the boost levels also increase beyond what the boost controller or stock settings were. Boost creep is typically more pronounced at higher rpm’s since there is more exhaust flow present for the Wastegate(s) to bypass. Effective methods of avoiding or eliminating boost creep include porting the internal Wastegate(s) opening to allow more airflow out of the turbine, or to use an external Wastegate(s).”

Read more at Cobb Tuning

Have Questions? Call Today!
(763) 316-5882