Gains are 125whp on pump gas and up to 260whp on higher octane or E85 mixtures.

The ultimate tune for your 4.4L V8 powered Land Rover Defender OCTA. The JB4 allows you to go from factory stock to full race and everywhere in between. The JB4 installs and removes easily and includes many unique features not found in any other tune, including user-adjustable 1st and 2nd gear boost limiting, smartphone integration, electronic wastegate control, ethanol fuel support, and built-in advanced CANbus-based diagnostic tools. Installation is easy and completely removable with no splicing or cutting of factory wires making the JB4 an excellent choice for your V8 OCTA engine.

No ECU flash needed and compatible with locked 🔒 ECUs

Wirelessly Connect to your JB4: Grab one of our smartphone connection options to wirelessly connect the JB4 BMW tuner to your Bluetooth 4.0 compatible iOS or Android device. 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.

JB4 Mobile by DMAC was released in 2014 and has become the gold standard for phone-to-tuner integration with its unique gauge display options/themes and advanced security systems. The JB4 Mobile app is purchased separately for $29 and requires the JB4 Mobile adapter.

JB4PRO by Burger Motorsports is our brand-new in-house adapter designed from the ground up for ease of use and reliability. 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. More information on the differences between the app options is available here.

JB4 FEATURES & BENEFITS

• Gains are 125whp on pump gas and up to 260whp on higher octane or E85 mixtures.
• Improves 0-60 times and 1/4 mile times
• Preloaded with custom OCTA JB4 tuning software and up to 8 maps for various fuel and modification levels
• Ethanol (E85) compatible tuning maps
• Able to read/delete fault codes
• View and record up to 40 gauges/engine parameters in real-time with the JB4 app.
• Boost by gear in 1st, 2nd, and 3rd can be controlled via the JB4 app for a perfect launch
• Compatible with JB4 Mobile for smartphone logging, tuning changes, and adjustment
• The JB4 offers a lot more performance, functionality, and safety than your average performance chip
• Quick Plug & Play Installation
• CANbus OBDII integration offering unrivaled tuning features and performance
• Improved performance over non-integrated chip tunes
• Runs as smoothly as stock. This is how your vehicle should have come from the factory
• Compatible with all driving modes
• Fuel economy unchanged during normal driving
• 91 octane fuel or better required for performance gains
• Not VIN locked and can be removed without a trace and resold down the road
• Includes the rugged JB4 billet aluminum enclosure for protection
• Made in the USA
• 5 year warranty

Vehicle Fitment

Land Rover
• 2025+ Land Rover OCTA 4.4L V8 Twin Turbo

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.