BMW G70 740i B58 — first impressions and tuning plans

Bimmercode already has partial support for the G70 — you can do ambient lighting, digital speedo, and most comfort coding. The seatbelt chime disable works too. Make sure you are on the latest Bimmercode version (4.33+) and use the WiFi OBD adapter, not Bluetooth — the G70 requires the faster connection for some modules.

For ECU tuning, the B58TU2 in the G70 uses the Bosch MG1CS201 DME which is the same family as the G80 M3. BM3 has been working on support but the encryption is a challenge. Last I heard from their Discord, they expect G70 support in Q2 2026. In the meantime, some tuners are offering bench-flash solutions where you remove the DME and flash it on the bench — not ideal but it works. Expect 430-450hp on a conservative stage 1 map.

The G70 is a tech showcase. I have been playing with the iDrive 8.5 system extensively — the voice assistant is actually usable now, and the integration with BMW Digital Key Plus means you can share your car key via iMessage. For coding enthusiasts, the G70 uses the newest MGU headunit which supports more customization than previous generations.

One thing to note: BMW has started locking certain coding options behind their ConnectedDrive subscription. Some features that were previously free to code (like enhanced Bluetooth audio streaming quality) now require an active subscription. This is a trend I expect to continue with newer models. For the Theatre Screen, make sure you update the rear entertainment firmware — the initial version had stuttering issues with 4K content that BMW fixed in a software update.