BMS S55 JB4 for 2015+ BMW M2C / M3 / M4


Gains are 60wkw / 135wnm on pump fuel and up to 90wkw / 190wnm on higher octane or E85 mixtures.

  • Please ensure your model is listed in the product description before purchasing!

Available on back-order


BMS S55 JB4 for 2015+ BMW M2C / M3 / M4

Gains are 60wkw / 135wnm on pump fuel and up to 90wkw / 190wnm on higher octane or E85 mixtures.

The ultimate tune for your S55 powered vehicle, the JB4 allows you to go from factory stock to full race, and everywhere in between, with the push of a button on your steering wheel.

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, map switching in dash, electronic wastegate control, ethanol fuel support, and built in advanced CANbus based diagnostic tools. Installation is completely removable with no splicing or cutting of factory wires.


For the latest performance results, updates, firmware, and map guide be sure to visit N54tech.com.


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.



Features & Benefits

  • Gains are 60wkw/135wnm on pump fuel and up to 90wkw/190wnm on higher octane or E85 mixtures.
    • Quick Plug & Play Installation
    • CANbus integration offering unrivaled tuning features and performance
    • Runs as smoothly as stock, this is how your BMW 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

S55 JB4 Applications

• 2018+ M2 Competition (S55 Engine)

• 2015-2019 F80 M3

• 2015+ F82 F83 M4, M4 GTS, M4 CS

BMS S55 BMW M3/M4 JB4 Map Guide

Map 0: Disable JB4 / Full Pass Through Mode
Map 1: Stage1 map adding approximately 40whp and 40wtq across the power band on pump gas. Suitable for all stages and fuel mixtures.
Map 2: Slightly more aggressive version of map 1 intended for vehicles with exhaust modifications and 93+ octane fuel. Can also be used with E85 and racing fuel mixtures.
Map 3: Slightly less aggressive version of map 1 intended for vehicles running on lower grade fuels such as 91 octane.
Map 4: OEM performance but with JB4 active for diagnostics only.
Map 5: //M low torque / linear throttle map.
Map 6: Custom tuning map.
Map 7: Race gas map. Requires 100 octane unleaded fuel and for the fuel mass connector to be installed. This map can also be used with up to 35% E85.
Map 8: Methanol injection map. Requires BMS FSB controller or methanol kit for progressive mapping and safety systems.







Change maps on the fly


JB4 S55 CAN flap demo




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