BMW M240i G42: ECU Unlock, Stage 1 + xHP Stage 3, 418bhp & 629Nm

This 2022 BMW M240i xDrive Coupé (G42) came in for our Stage 1 custom dyno tune for its B58 3.0 straight-six, with an xHP Stage 3 calibration for its ZF 8-speed gearbox, both developed on the same visit.

ECU unlocked in-house first

Built after June 2020, this M240i has a locked ECU, so it can’t be read or tuned through the OBD port as it comes. We unlocked it in-house, saved the original file, then carried straight on with the calibration.

The numbers

On the baseline run it made 381.3bhp and 555Nm. With our calibration and xHP Stage 3 it made 418.3bhp and 629Nm, with 354.7bhp at the wheels. That is 37.0bhp and 74Nm more:

More torque than a G87 M2

The gain is not just at the peak. Tuned, this M240i holds over 600Nm from around 2,700 to 3,850rpm, with up to 80Nm more torque in the mid-range, and stays above 400bhp from around 5,350 to 6,000rpm. For reference, BMW’s G87 M2 makes 550Nm (600Nm for the later automatic). xHP Stage 3 removes the gearbox’s torque limiters and rescales the shift pressures for the extra torque, with firmer, faster upshifts in Sport and Sport+ and stronger blips on the downshifts.

How it was done

Diagnostics and a health check first, then baseline runs on our 4WD linked dyno with live data logging. The engine calibration was built from there with repeated runs, the gearbox was flashed with xHP Stage 3, and the final pulls verified the result. No generic files: a calibration written for this car, proven on our dyno.

Got an M240i? See our BMW 2 Series tuning page and B58 tuning page, check your car’s gains and price, or read about tuning the M140i and M240i.