Description
JB4 Tuner for Subaru WRX, Ascent, Legacy & Outback – Up to 50 HP Gains on Stock Turbo Engines
Unlock your Subaru’s full turbocharged potential with the JB4 Tuner, the most advanced plug-and-play ECU performance upgrade for 2.4L 4-cylinder turbo engines. Designed for the WRX, Ascent, Legacy XT, and Outback XT, the JB4 delivers power gains of up to 50 horsepower at the wheels (70 hp crank) on a completely stock vehicle. With ethanol blends (E85) or additional bolt-on modifications, gains can be even higher.
The JB4 connects directly to your vehicle’s sensors and works seamlessly with your factory ECU, intelligently remapping boost, timing, and fueling while maintaining all factory safety systems. With full CANbus integration, the JB4 monitors engine data in real-time, providing advanced safety features such as progressive boost control, automatic low-boost mapping during overheating, knock mitigation, and lean-run protection.
Wireless JB4PRO Connectivity
The JB4 now includes the JB4PRO Bluetooth adapter and free smartphone app, allowing wireless connection to iOS and Android devices. Effortlessly switch between performance maps, monitor real-time engine parameters, record data logs, and receive free firmware updates as new maps and features are released. The adapter is fully enclosed within the JB4 housing for enhanced weather protection and a sleek, low-profile appearance. The JB4PRO app features an intuitive interface, advanced log analysis tools, and real-time performance estimation, giving you full control over your Subaru’s performance.
Key Features & Benefits:
- Power gains up to 50 hp at the wheels on a stock vehicle
- Improves 0-60 acceleration and quarter-mile performance
- Multiple performance maps for pump gas and E85 ethanol
- Quick plug-and-play installation, fully removable, and non-VIN locked
- Reads and clears fault codes; logs up to 40 engine parameters
- Boost-by-gear control for enhanced traction
- Controls exhaust flap operation on supported vehicles
- Compatible with the free JB4PRO smartphone app
- Offers better performance and safety than standard chip tunes
- Maintains smooth operation across all driving modes
- No impact on fuel economy during normal driving
- Requires 91 octane or higher for optimal performance
- Premium billet aluminum enclosure, designed and assembled in the USA
- 5-year warranty
Vehicle Compatibility:
- 2022+ Subaru WRX 2.4L 4-cylinder turbo
- 2019+ Subaru Ascent 2.4L 4-cylinder turbo
- 2020+ Subaru Legacy XT 2.4L 4-cylinder turbo
- 2020+ Subaru Outback XT 2.4L 4-cylinder turbo
Why Choose JB4?
The JB4 is a true plug-and-play tuner for Subaru turbo engines, offering ECU-level adjustments to boost, timing, air/fuel ratio, and fuel trims. Unlike basic chips, JB4 leverages CANbus integration and advanced sensor monitoring to deliver safe, smooth, and significant performance gains. Free firmware and map updates from BMS continually enhance performance, add new features, and improve safety. Non-VIN locked and fully removable, the JB4 can be transferred between vehicles or resold, making it the gold standard in Subaru turbo tuning worldwide.
