NEWS
Pre-chamber ignition for BMW M cars
Straight-six BMW M cars receive race-inspired tech, but, curiously, no extra power
n BMW is introducing pre-chamber ignition into its straight-six M engine, the 3-litre twin-turbocharged motor known as the S58. Not to boost power or performance, as the output of the engines with the new ignition system will have the same output, but instead, to increase efficiency. M Ignite, as BMW has called this new technology, plays a major role in getting the straight-six performance engine, which puts out between 480hp and 550hp, to meet stringent Euro 7 standards.
The adapted S58 will, from this Summer onwards, feature a prechamber device with its own spark plug contained within a housing perforated with seven holes. Under load and at high rpm, the new system is active, and it’ s here where the efficiency of the engine is improved dramatically. Within the pre-chamber, the fuel and air mixture is ignited and the flames exit through the seven holes into the main combustion chamber at around the speed of sound. This fills the combustion chamber more completely, improving combustion speed and getting as much bang from the fuel as possible.
Not only is the engine’ s efficiency improved, but BMW M Ignite reduces exhaust gas temperatures and counters the causes of knocking, which has allowed the updated engine to run a higher compression ratio. The new pre-chamber ignition-equipped S58 will also feature variable turbine geometry turbochargers. But still, no extra power for the M2, M3 and M4 that will receive these upgrades. Not yet, anyway.
Pre-chamber ignition will allow BMW’ s performance straight-six to conform to strict emissions criteria
6 The Engine Rebuilder Issue 05