Description
Unlock the true performance potential of your Ford Focus RS or ST with the JB4 Tuner, a plug-and-play tuning solution designed specifically for turbocharged EcoBoost® engines. Delivering up to 50whp and 60wtq to the wheels, the JB4 improves acceleration, reduces turbo lag, and provides smooth, reliable power across all driving modes—without flashing your ECU.
Discrete, Fully Removable Installation
The JB4 plugs into two easily accessible sensors in the engine bay, working seamlessly with your factory ECU to optimize boost, timing, and fueling. Unlike flash remaps, the JB4 is fully removable, leaving no trace when uninstalled. Fuel economy remains unchanged during normal driving.
Advanced CANbus Integration
Equipped with a 64MHz processor and advanced sampling technology, the JB4 monitors critical engine parameters up to 800 times per second. Its CANbus system reads and reacts to pedal input, throttle position, gear, engine speed, air/fuel ratio, ignition timing, knock, and fuel trims in real time. Safety features include:
- Low boost until engine oil and water reach proper temperature
- Automatic drop to low-boost map in case of overheating, knock, lean conditions, or overboost
Versatile Tuning Maps
- Default Map 1: +4psi peak over stock
- Stock, VALET, and fully tunable maps
- Support for 91 and 93 octane, and E85 ethanol blends
- Boost-by-gear control for improved traction
- Fault code reading and deletion
Wireless JB4PRO Connectivity
The JB4PRO adapter connects wirelessly via Bluetooth 4.0 to iOS and Android devices. Using the free JB4PRO app, you can:
- Switch between performance maps
- Record and analyze vehicle and tuning data
- Update firmware for free enhancements
- Access advanced log analysis tools
Performance and Reliability Benefits
- Up to 50whp and 60wtq on stock vehicles
- Improves 0-60 mph and quarter-mile times
- Smooth, stock-like operation across all driving modes
- Supports E85 ethanol blends
- Plug-and-play installation with no splicing or cutting
- Fully removable and not VIN-locked
- Logs up to 40 engine parameters
Quality and Warranty
- Billet aluminum enclosure
- Designed and assembled in the USA
- 5-year warranty
Vehicle Fitment:
- 2016+ Ford Focus RS
- 2016+ Ford Focus ST
Why Choose JB4?
For over a decade, the JB4 has been the gold standard in plug-and-play turbocharged performance tuning. By tapping into CANbus and sensor data in real time, it delivers safe, smooth, and significant power gains while retaining factory safety systems and leaving your ECU unaltered.
