JB4 – BMW S55 M3 M4 M2 competition 

The BMW S55 engine is found in the M3, M4 and the new M2 competition. With already impressive stock power figures, once tuned the BMW S55 becomes a real super car slayer!

The ultimate S55 BMW M3 M4 M2C tuning box is the JB4. You can install the S55 JB4 in multiple configurations to suit your needs. A more simple stage 1 configuration connected to just the MAP & TMAP will allow you to run modest boost levels where you can expect approx 480bhp. In the full fat configuration connected to the fuel rails and electronic wastegates, you can run high boost maps for ethanol blends and race fuels where you can expect well over 500bhp. Installation is simple, with a novice being able to complete in under 2 hours for the first time.

For users who want even more power, the S55 JB4 has fully integrated meth injection mapping. With the optional BMS Meth kit the S55 JB4 can control boost as a function of meth flow with full safety. This means that if the meth is not flowing, the JB4 will know, and it will not request the boost and keep things safe. No other S55 tuning box has close to this functionality on the market, or can achieve the power figures. 

With the optional JB4 bluetooth connector, you can take advantage of the many features of the S55 JB4. These include data logging, code read / write, passive delete for EML delete when decats are fitted, boost by gear, and much more.

The BMW S55 JB4 is truly future proof and supports stage 1, stage 2, and stage 3 levels of tune.

S55 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 98+ 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 95 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 methanol kit for progressive mapping and safety systems.