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.

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, optional in-dash gauge displays for boost, boost limiting by gear for improved traction in lower gears, progressive water/methanol support, built-in data logging, built-in code reading, optional direct EWG control to prevent throttle closure with exhaust modifications, exhaust flapper control, 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 BMS DATA cable or JB4 mobile phone adapter. The JB4 automatically detects between the B38, B46, B48 models at boot up making installation and setup a snap.

Wirelessly connect the JB4 to your Bluetooth 4.0 compatible iOS and Android device via the JB4 Mobile connect kit or to your Windows laptop with the BMS data cable. Both options allow 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. A separate JB4 Mobile app purchase is also required.

JB4 Map Guide:

Map0: Stock tuning, fully disable JB4
Map1: 3psi over stock added (91 octane)
Map2: 4psi over stock added (91-93 octane)
Map3: 6psi over stock added (93+ octane)
Map4: Absolute target map with peak target of 20psi (93+ and/or 30% E85, EWG connector suggested)
Map5: Absolute target map with peak target of 22psi (30% E85+ fuel, EWG connector suggested)
Map6: Custom tuning map — see details on JB4tech.com B58 JB4 page
Map7: Progressive WMI map with tuning a function of meth flow and user-defined boost additive.
Map8: VALET / Low Boost Map

Note for 2018+ G chassis vehicles with the digital dash layout we have not yet added in the JB4 commands to allow in-dash control but will provide those via a free firmware update once developed. Until then a JB4 mobile adapter or BMS data cable is required for any map and setting changes.

JB4_B58 is CARB Approved Under Executive Order (EO) No.D-744-4 for all 2016-2018 BMW 230i, 330i, 430i, 530i, 340i, 440i, 740i, M240i, and X1 applications.

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.

California Customers — Download the CARB Version Installation Guide

2018 BMW 330i with JB4, intake, exhaust

2017 BMW 230i with B48 Engine, JB4