Ready to take your BMW N20 turbo to the next level? How about up to 50hp to the wheels (65hp crank) on a completely stock car or up to 100hp to the wheels (120hp crank) on a fully modified car? The JB4 features a simple plug and play installation harness for easy installation and includes many features not found on any other tune. Including the ability to enable/disable the tuning from the drivers seat, gear dependent boost control to help with traction, E85 compatibility, built-in diagnostic code reading/deleting, expanded engine safety systems, free firmware updates, in-dash boost gauge, the ability to control the exhaust flapper using your BC button, and much more.

The JB4 does not require any additional modifications or previous stages. Simply install the JB4 as your first and only modification and enjoy an entirely new fast and smooth racing experience. For more advanced enthusiasts the BMS DATA or JB4 Mobile cable allows you to connect a laptop or smartphone for additional gauges, data logging, and free firmware updates as we add new features and maps.

The JB4 is a full plug and play device that installs and removes in minutes at home without special tools and unlike flash maps that permanently write over your DME with the JB4, your DME is never aware it’s running more than the factory power levels. And when you’re ready to change things up the JB4 is not VIN locked and can be moved to your next vehicle or resold.

Wirelessly connect the JB4 to your Bluetooth 4.0 compatible iOS and Android device via the JB4 Mobile connect kit, or to your Windows laptop with the BMS data cable. 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. Separate JB4 Mobile app purchase also required.

NOTES: The X1 & Z4 N20 JB4 is very different than the F series N20 JB4. They use special firmware (with full dash control) and have a different CAN mounting location. For that vehicle, please click HERE. 

PLEASE CONFIRM WHICH VERSION YOU NEED BASED ON THE PICTURE BELOW:

All versions of this tuner linked below for your vehicle(s):

Pneumatic Wastegate – 2012-2016 BMW 228, 328, 428, 528, X3 (THIS PART)

Electronic Wastegate – 2012-2016 BMW 228, 328, 428, 528, X3 (LINKED HERE)

E Series – X1 & Z4 (LINKED HERE)

N55 JB4 Features and Benefits 

• Power gains of up to 50hp and 60tq to the wheels on a stock vehicle
• Quick Plug & Play Installation
• CANbus integration offering unrivaled tuning features and performance
• Runs as smoothly as stock, this is how your N20/N26 should have come from the factory
• Compatible with all driving modes
• Fuel economy unchanged during normal driving
• Compatible with JB4 Mobile for smartphone logging, tuning changes, and adjustment
• Ethanol (E85) compatible tuning maps
• Able to read/delete fault codes
• Not VIN locked, can be removed without a trace and resold down the road
• Made in the USA
• Free USA Shipping
• 5 year warranty

Download JB4 iPhone App

Download JB4 Android App

DYNO RESULTS

328i on pump gas dyno

320 JB4 dyno

328 E85 dyno