I was just wondering if anyone else had concerns about the addition of the new 48-Volt mild hybrid system for the MY2021 540i and 540i xDrive Sedans potentially making this already fantastic B58 drive train less suitable for installing a downpipe and a tune.
Maybe it's just me, but the extra weight of a second battery, plus all the extra electrics just seems to add future high cost maintenance expenses, unnecessary complexity and additional points of failure.
As for me, I would have much rather seen the inclusion of the 382hp version of the B58 and done away with the extra electrics.
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"A new mild hybrid system with a 48V starter-generator offers enhanced performance, better efficiency and improved driving comfort in the six-cylinder BMW 5 Series.
A powerful 48V starter-generator and a second battery greatly increases the ways in which Brake Energy Regeneration can be utilized. When the driver releases the accelerator, the generator transforms the kinetic energy into electricity to be stored in the 48V battery. Energy recuperation benefits even more when the Driving Experience Control switch is set to SPORT mode. The additional deceleration generated over and above the engine braking effect is also harnessed when the brakes are applied. A specially designed braking system previously found in BMW’s plug-in-hybrid models enables the combination of electrical and mechanical deceleration to be deployed as required and with maximum efficiency at all times.
The recuperated energy accumulating in the 48V battery is supplied to the 12V electrical system and powers the lights, steering, power windows, ventilation, audio system and seat heating. In addition, the stored energy can be used to provide additional drive power when it is fed back to the 48V starter-generator.
The starter-generator then acts likes an electric drive unit that assists the engine, allowing it to operate within a more efficient range as frequently as possible and ensuring there are fewer peaks in fuel consumption. When the car is accelerating, the 48V starter-generator is able to offer the driver an electric boost effect that can instantly put an extra 11 hp on tap for more dynamic power delivery. The result is a sharper response off the line and quicker bursts of speed when accelerating.
A special feature of the mild hybrid system is the ability to charge the 48V battery from the generator while driving at a constant speed. This method of generating electricity by raising the engine’s load point is only employed when the battery charge is low and during phases when it does not have a detrimental effect on engine efficiency.
The 48V starter-generator has the additional benefit of allowing the engine to be switched off and started again very swiftly with less vibration. The result is improved comfort when the Auto Start Stop and coasting functions are in use. When the driver brakes for a stop, the engine can be switched off as soon as the car’s speed drops below 9 mph. And if the coasting function is activated, the engine is also completely shut off rather than just being decoupled from the drivetrain. This function is now operational at speeds between 16 – 99 mph and, on the new BMW 5 Series, it is available not just in ECO Pro mode but also COMFORT mode."
