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.

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, 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 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.

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.

B38/B46/B48 Vehicle Fitment

Note: If your BMW has a B38/B46/B48 engine and you don't see your exact model on the list below please email us.

BMW 1 Series
• 2019-2024 F40 F40 M135i
• 2020+ F40 B48 BMW 128ti
• 2019-2019 F40 B38 BMW 118i
• 2016-2019 F20/F21 B48 BMW 120i, 125i
• 2015-2019 F20/F21 B38 BMW 116i, 118i

BMW 2 Series
• 2022+ G42 B48 BMW 220i, 230i
• 2017-2021 F22 F23 B48 BMW 230i including xDrive
• 2017-2021 F22 F23 B48 BMW 225i including xDrive
• 2017-2021 F22 F23 B46 BMW 220i including xDrive
• 2015-2021 F22 F23 B38 BMW 218i
• 2015-2021 F45 F46 B38 BMW 216i Active tourer and GT
• 2014-2020 F45 F46 B38 BMW 218i, 220i Active tourer and GT
• 2019+ F44 B48 BMW M235i Gran Coupé including xDrive

BMW 3 Series
• 2019+ G20 G21 B46 B48 BMW 318i, 320i, 320Li, 320e, 330i, 330e, 320Li including xDrive
• 2016-2018 F30 B48 BMW 330i, 330e including xDrive
• 2016-2018 F30 B48 BMW 325i including xDrive
• 2016-2018 F30 B46 BMW 320i including xDrive
• 2016-2018 F30 B46 BMW 318i including xDrive

BMW 4 Series
• 2021+ G22 G23 G26 B48 BMW 420i, 430i including Gran Coupe and xDrive
• 2016-2020 F32 F33 F36 B48 BMW 430i including Gran Coupe and xDrive
• 2016-2020 F32 F33 F36 B48 BMW 425i including xDrive
• 2016-2020 F32 F33 F36 B46 BMW 420i including xDrive
• 2016-2020 F32 F33 F36 B38 BMW 418i

BMW 5 Series
• 2017-2023 G30 B46 BMW B48 530i 530e including xDrive
• 2021-2023 G30 BMW 545e

BMW 6 Series
• 2018+ G32 G33 B48 BMW 630i including xDrive

BMW 7 Series
• 2016-2022 G11 G12 B48 BMW 730i including xDrive

BMW X Series
• 2016+ F48 B46 B48 BMW X1 28i including xDrive
• 2018+ F47 B46 B48 BMW X2 28i including xDrive
• 2018+ G01 B48 BMW X3 2.0i, X3 3.0i including xDrive
• 2019+ G02 B48 BMW X4 2.0i, X4 3.0i including xDrive
• 2019+ G05 B48 BMW X5 30i including xDrive

BMW Z4
• 2019+ G29 B46 B48 BMW Z4 30i and Z4 20i