BMW B38 B46 B48 JB4 Tuning Box with PRO Bluetooth App

The JB4 is the definitive piggyback ECU for BMWs with B38, B46 and B48 engines - no ECU flashing, no VIN lock, full plug-and-play fitment.

• Real-time map switching: stock, pump fuel, high-octane, E85 or valet mode - all from your dash
• Free iOS/Android app for live logging, tuning and firmware updates
• Boost-by-gear, wastegate control, exhaust flap management and WMI support
• Gains ~40 whp on stock B48; scales cleanly with bolt-ons or ethanol
• Rugged USA-built billet housing, 5-year warranty, works with all OEM driving modes