Power gains of up to 130WHP on a stock vehicle without the risks of flashing!

The JB4 is the most advanced and highly featured tuning system available for your B48/B58 GEN3 powered vehicle. Power gains are up to 100whp to the wheels (125hp crank) on a completely stock car on 93 octane, and even higher with ethanol fuel mixed in!

This new JB4 BMW tuner is specifically designed for the latest Gen 3 B48/B58 variant and is capable of processing the new ultra fast SENT digital sensor signals in real time with zero latency. The JB4 features a simple plug & play installation harness for easy installation & removal and includes many features not found with any other tune. Including on the fly in-app map switching between factory and various performance maps, boost limiting by gear for improved traction in lower gears, progressive water/methanol support, built-in data logging, built-in code reading, and much more. Other more expensive tuners may claim to equal the JB4's technology but upon closer examination lack most if not all of the JB4's features.

Remember the JB4 does not require any additional modifications or previous stages. Simply install the JB4 as your first and only modification and enjoy an entirely new fast and smooth racing experience. The JB4 also does not require any user setup or customization, but for those who are interested in logging, adding new features as we post them, etc, we suggest the Bluetooth mobile phone adapter.

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 Power Gains, Features, & Benefits

• Power gains of up to 130hp to the wheels on a stock vehicle
• 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.

Vehicle Fitment (GEN 3 B48/B58)

⚠️This only fits the exact vehicles below. Does not plug into previous years B48/B58 engines due to different connectors on the newer B48/B58 engines. Click here for previous generation B58 engines.

BMW 2 Series
• 2023+ F44 B48 GEN3 BMW 228i xDrive Gran Coupe

BMW 3 Series
• 2025+ G20 G21 B58 GEN3 BMW M340i including xDrive
• 2025+ G20 G21 B48 GEN3 BMW 330i 330e 320i including xDrive

BMW 4 Series
• 2025+ G22 G23 G26 B58 GEN3 BMW M440i including Gran Coupe and xDrive
• 2025+ G22 G23 G26 B48 420i, 430i including Gran Coupe and xDrive

BMW 5 Series
• 2024+ G60 G61 B58 GEN3 BMW 540i including xDrive
• 2024+ G60 G61 B48 GEN3 BMW 530i, 530e including xDrive

BMW 7 Series
• 2023+ B58 GEN3 G70 BMW 740i

X Series
• 2023+ U11 U12 B48 GEN3 BMW X1 28i and xDrive28i
• 2024+ U10 B48 GEN3 BMW X2 xDrive28i and M35i xDrive
• 2025+ G45 B58 GEN3 X3 M50 xDrive
• 2024+ G05 B58 GEN3 BMW X5 M40i and xDrive40i
• 2024+ G06 B58 GEN3 X6 xDrive40i
• 2022+ G07 B58 GEN3 BMW X7 xDrive40i

⚠️ ATTENTION: Verify fitment above and below. Failure to do so will result in a restocking fee. 

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 the 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.

JB4 is compatible with factory over-the-air software updates. 
Unlike flash tunes, which can be erased during an iDrive or dealer software update, JB4 does not overwrite the factory ECU software.

Gen 3 B48 Install Guide

Gen 3 B48 Install Guide (Transversely Mounted)

Gen 3 B58 Install Guide

GEN 3 B58 Shocking Dyno Reveal: Our 2025 BMW M340i Pushes "30PSI

Stock vs. JB4 Dyno Results

2023 G70 BMW 7 Series 740i B58, no other mods