BMW G42 M240i: fix the heat first, then the sound

The B58 is strong but the stock cooling is cut back and the exhaust is tame. An M240i gets an uprated intercooler, side coolers and a valved exhaust.

BMW G42 M240i: fix the heat first, then the sound

The stock B58 makes serious power, but the factory cooling is trimmed back and the exhaust is tame. A few hard pulls in the heat and it fades — the straight-six character gets buried.

Cooling: uprated intercooler + left/right side coolers

This car received a Speedtune uprated intercooler plus left and right auxiliary coolers, filling in what the factory cooling system left on the table. With cooling efficiency up, intake temperatures stay stable and the power fade during hard driving or hot-weather high-rpm runs is essentially gone. It is more relaxed day to day, and there is headroom left for a later tune — power delivery feels more linear and responsive.

Sound: valved cat-back

A direct bolt-on install with no cutting, reducing exhaust backpressure and freeing up power. With the valve closed it stays quiet and compliant; open, the straight-six has proper depth and the overrun note is there.

Who it suits

M240i owners who do not want a shouty car but do want to drive it properly. Cooling and sound together are the two most practical steps.