BMW B38/B46/B48 JB4 Tuner

Power gains of up to 100HP on a stock vehicle without the risks of flashing!

The JB4 is the most advanced and highly featured tuning system available for your B38, B46, and B48 powered BMW. Power gains are up to 40hp to the wheels (55hp crank) for a B48, gains with bolt-on parts, higher octane, E85 mixtures, and larger turbos are even higher. Now includes the JB4PRO adapter and free app built in!

No ECU flash needed and compatible with locked ECUs

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-dash 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, direct EWG control to prevent throttle closure with exhaust modifications, exhaust flapper control (most models), 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 it 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 changing maps, logging, customization, and loading new features as we add them, we suggest adding one of our Bluetooth phone adapters!

The JB4 automatically detects between the B38, B46, B48 models at boot up making installation and setup a snap.

Wirelessly Connect to your JB4:Our all-newJB4 PROsmartphone 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 theJB4PRO mobile app