JB4 Tuner — BMW S58 X3M & X4M (F97/F98)
Around 80whp and 100wtq on pump gas, and up to 150whp / 175wtq on higher octane or E85 — without flashing the ECU. The JB4 works through the S58's sensor network and CANbus, so it runs on locked DMEs and survives BMW's over-the-air updates. Plug-and-play install, no wire splicing, fully reversible.
JB4 or JB4PRO?
Both include the JB4PRO Bluetooth adapter and the free app. Wireless map switching, live gauges, datalogging and firmware updates from your phone are standard either way — the PRO is not "the one with Bluetooth."
The JB4PRO is a different board built for heavily modified cars. On top of everything the standard JB4 does, it adds:
- Direct ethanol sensor control
- Port injection / CPI / WMI control via the PnP add-on harness
- Fuel pressure control for advanced tuning on ethanol mixtures — built in, no upgrade kit needed
- Onboard datalogging memory
- Additional high-current outputs for extra pumps, relays and solenoids
- Additional inputs for monitoring external sensors
- Bluetooth and memory on the board itself rather than via the adapter
- CANbus integration with flash tuning
Stock or bolt-ons? The standard JB4 is the right call. Building toward E85, port injection or meth? Go PRO.
What it does
- Multiple switchable maps including E85 ethanol blends
- Boost-by-gear limiting for traction in the low gears
- Live gauges, datalogging, fault code read and clear over CANbus
- Not VIN-locked — transfers between cars
- Free firmware updates · 5-year warranty · designed and assembled in the USA
VEHICLE APPLICATIONS
| Make / Model | Chassis | Engine | Years |
|---|---|---|---|
| BMW X3M | F97 | S58 | 2020+ |
| BMW X3M Competition | F97 | S58 | 2020+ |
| BMW X4M | F98 | S58 | 2020+ |
| BMW X4M Competition | F98 | S58 | 2020+ |
Driving a G80 M3, G82/G83 M4 or G87 M2? Use the S58 JB4 for those chassis instead.
Running E85 on a standard JB4?
Add the JB4 Fuel Pressure Upgrade Kit for direct fuel pressure and fuel trim control. Skip it if you're buying the JB4PRO — that's already built in.
Prefer a flash tune?
We also carry the MHD Super License and the bootmod3 tune for the S58.