Power gains of up to 80WHP horsepower on pump gas and up to 150WHP on race gas on a stock vehicle without the risks of flashing!

The ///M JB4 takes everything that is great about the all-wheel-drive F9x M5 & M8 platform and amps it up to the next level. Power gains of up to 80whp and 100wtq bring the car to life allowing 1/4 mile potential deep into the 10s. Unlike other generic tuning devices, the JB4 includes full CANbus integration via the OBDII port for advanced tuning, safety features, and diagnostics, as well as electronic wastegate control for superior boost targeting. This is simply the best tuning box available for your ///M.

Now includes the JB4PRO adapter and free app built in!

No ECU flash needed and compatible with locked 🔒 ECUs

Installation is fully reversible attaching to the TMAP sensors and OBDII port. The included electronic wastegate (EWG) wires are optional and allow the JB4 to take direct control of the wastegates for more precise boost targeting for higher boost maps. Firmware update loaded via JB4 Mobile or a BMS Data Cable will be provided free of charge as we expand the JB4's performance, maps, and features with future development.

JB4 Features & Benefits

• Power gains of up to 80hp and 100tq 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

M5
• 2018-2024 S63 BMW F90 M5, M5 Competition, and CS M8

M8
• 2020-2025 S63 BMW F92 M8 Coupe and M8 Competition
• 2020-2026 S63 BMW F93 M8 Gran Coupe
• 2020-2025 S63 BMW F91 M8 Convertible X Series

X Series
• 2020-2023 S63 BMW F95 X5M and X5M Competition
• 2020-2023 S63 BMW F96 X6M and X6M Competition

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.

BMW F90 M5 JB4 Install Video

Dyno Results

2018 F90 M5, All stock with JB4

Dragy Results

2022 F90 BMW M5 JB4 Map 6 + 100 octane. 9.98 @ 138 mph

2020 F92 BMW M8 with JB4, MAP 5, BMS Intake, and MS109 Race Gas