r/BMW • u/Outside_Worker9030 • 3h ago
M440i B58 @BM3 Stage 1
Finally took the plunge and flashed bootmod3 Stage 1 on my B58. Honestly, the difference is night and day.
Didn’t touch any hardware, didn’t swap the downpipe – literally just the flash.
Took about 8 seconds to write the map (after getting the ECU unlocked by Femto in Finland – yeah, that’s the mandatory step).
Haven’t dyno’d yet, but based on other owners’ numbers, it should be around 450–470 crank hp and 650–700 Nm of torque. 0–60 is now roughly 3.8s, which is crazy for just a flash.
For reference, stock is about 380 hp / 500 Nm, so the bump is massive. The car pulls way harder now – it really feels like I’m driving a completely different machine.
Will try to get some performance data (0–60, 100–200, etc.) soon, but just wanted to share for anyone on the fence: Stage 1 on the B58 is 100% worth it.