Gains are up to 80whp/100tq on pump gas and up to 120whp/140wtq on higher octane or E85 mixtures without the risks of flashing!

The ultimate tuner for your S55 powered vehicle, the JB4 allows you to go from factory stock to full race, and everywhere in between with the push of a button on your steering wheel or phone. The JB4 installs and removes easily and includes many unique features not found in any other tune, including user adjustable 1st and 2nd gear boost limiting, map switching in dash, electronic wastegate control, ethanol fuel support, and built-in advanced CANbus based diagnostic tools. In addition, installation is completely removable with no splicing or cutting of factory wires.

Now includes the JB4PRO adapter and free app built in!

No ECU flash needed and compatible with locked 🔒 ECUs

The JB4 is compatible with the factory flash map, competition package flash map, all off-the-shelf flash maps, custom tuned flash maps, or any flash map you choose to load! For those who don't mind flashing BMS provides free back end flash maps designed to optimize performance for specific builds and fuels saving you hundreds of dollars and many hours of time on custom flash tuning.

For the latest performance results, updates, firmware, and map guide click here.

For those running aftermarket turbocharger systems with aftermarket Tial wastegate(s) we have a special version of the S55 JB4 specifically to control them. Please email us so we can manually invoice you for the JB4_S55_TIAL version.

Wirelessly Connect to your JB4: Our all-new JB4 PRO smartphone connection is included to wirelessly connect the JB4 tuner to your Bluetooth 4.0 compatible iOS or Android device. This option allows you to record and analyze vehicle and tuning data, change JB4 performance maps, and update JB4 firmware as we release free newer versions with updates, more powerful maps, and new features under development. Our new adapter fits fully inside the JB4 enclosure for enhanced weather protection and a more streamlined look. The JB4PRO Free app features an intuitive easy-to-use interface, help buttons, and advanced log analysis tools that can estimate the performance of your car and help identify any tuning concerns. 

For more information about the JB4PRO mobile app click here.

JB4 Features & Benefits

• Gains are 80whp/100tq on pump gas and up to 120whp/140wtq on higher octane or E85 mixtures.
• Improves 0-60 and quarter mile times.
• Includes multiple tuning maps for different fuel types.
• Quick plug and play installation.
• Supports E85 ethanol blends.
• Reads and deletes fault codes.
• Displays and logs up to 40 engine parameters.
• Boost by gear control for improved traction.
• Controls exhaust flap operation on supported vehicles.
• Compatible with the free JB4PRO app.
• Offers better performance and safety than basic chip tunes.
• Full CANbus integration.
• Runs as smoothly as stock.
• Compatible with all driving modes.
• No impact on fuel economy during normal driving.
• Requires 91 octane or better for performance gains.
• Not VIN locked and fully removable.
• Includes billet aluminum enclosure.
• Designed and assembled in the USA.
• 5-year warranty.

S55 JB4 Vehicle fitment

BMW M2
• 2018-2022 S55 BMW F87 M2 Competition (S55 engine only)
Click here for N55 powered M2

BMW M3
• 2015-2020 S55 BMW F80 M3

BMW M4
• 2015-2020 S55 BMW F82 F83 M4, M4 GTS, M4 CS

What is a JB4?

The JB4 is a plug & play tune available for turbocharged vehicles. The JB4 tuner installs between your car's sensors and its DME/ECU (computer) and manipulates vehicle performance through these connections making your vehicle much faster. While it's not the only tuning system that operates this way the JB4 separates itself from the competition with much more advanced connection points and processing including CANbus, fuel & spark control, Bluetooth to your smartphone, and a variety of innovative and advanced features not possible with any other system. BMS regularly publishes free mapping and firmware updates adding performance and features as ongoing development allows. In addition, the JB4 system is not VIN-locked to your vehicle and can quickly be removed and swapped between cars or resold at a later time. Often imitated but never duplicated the JB4 has been the gold standard in plug and play turbocharged performance tuning for over a decade and is sold in over 67 countries worldwide.

Is the JB4 a real tune?

Yes the JB4 is a real tune. By tapping into specific sensors and CANbus for real time vehicle data the JB4 is able to alter your boost, timing, AFR, and/or fuel trims, to a similar degree an ECU reflash would, but without the vehicle ever knowing its been tuned. The result is safe, smooth, and significant power and torque gains while retaining your factory safety systems and without having to unlock/flag your ECU.

S55 BMW M3/M4 JB4 Map Guide
Map 0: Disable JB4 / Full Pass Through Mode
Map 1: Stage1 map adding approximately 40whp and 40wtq across the power band on pump gas. Suitable for all stages and fuel mixtures.
Map 2: Slightly more aggressive version of map 1 intended for vehicles with exhaust modifications and 93+ octane fuel. Can also be used with E85 and racing fuel mixtures.
Map 3: Slightly less aggressive version of map 1 intended for vehicles running on lower grade fuels such as 91 octane.
Map 4: OEM performance but with JB4 active for diagnostics only.
Map 5: //M low torque / linear throttle map.
Map 6: Custom tuning map.
Map 7: Race gas map. Requires 100 octane unleaded fuel and for the fuel mass connector to be installed. This map can also be used with up to 35% E85.
Map 8: Methanol injection map. Requires BMS FSB controller or methanol kit for progressive mapping and safety systems.

DYNO RESULTS

Change maps on the fly

JB4 S55 CAN flap demo