Yesterday, Frank van Meel, CEO of BMW M, confirmed what we’ve been writing about for months: the next-generation BMW M3, codename G84, will retain its straight-six engine and be launched alongside the iM3 ZA0 EV. He mentioned in an interview that the M3 will continue to use a six-cylinder 3.0 liter engine, but he stopped short of confirming which engine variant will that be. One thing is clear though: The G84 M3 won t be a PHEV like the larger M5. Instead, according to our sources, BMW will introduce a 48-volt mild-hybrid system a more refined approach for a performance-focused sports sedan.
Why No PHEV for the M3?
There are several reasons why the M3 won t follow the M5’s plug-in hybrid path. Firstly, the addition of a large battery pack would significantly increase the vehicle s weight, which could compromise the M3 s agility and dynamic handling characteristics. Weight management is a key factor in keeping the M3 true to its motorsport roots, and adding a bulky battery system would undermine this essential quality.
Secondly, the customer base for the M3 differs from those who might choose a plug-in hybrid for daily electric driving. M3 owners typically prioritize performance and excitement over all-electric daily driving. A good comparison is the customer profile for the new Porsche 911 hybrid, which focuses on performance over electric range a mindset shared by BMW M3 buyers.
Lastly, the packaging constraints play a pivotal role. The M3 is obviously smaller than the M5, making it challenging to incorporate the complex mechanicals of a PHEV without compromising interior space and balance. A PHEV setup would require not only room for a battery pack but also additional cooling and electrical infrastructure, which are easier to accommodate in the larger M5.
The Mild-Hybrid Approach
Instead of going the PHEV route, BMW will equip the next G84 M3 with a 48-volt mild-hybrid system. Mild-hybrid technology works by providing supplementary electric assistance to the internal combustion engine, particularly during coasting, and enhancing functions like automatic start-stop. However, unlike a PHEV, a mild-hybrid system cannot operate independently from the combustion engine.
BMW s mild-hybrid technology brings several advantages to the M3, including the highly publicized eBoost function. This feature delivers additional horsepower with minimal lag, utilizing the 48-volt power supply and starter motor to enhance acceleration. The generator, powered by a lithium-ion battery, is cleverly integrated into the engine s belt drive, ensuring smooth power delivery. This system doesn t transform the M3 into a hybrid powerhouse but enhances performance with minimal weight gain, staying true to the car s Ultimate Driving Machine slogan.
The Engine Question: S58 or B58?
One of the biggest uncertainties surrounding the next-gen M3 is the engine choice. The current M3 is powered by the S58 twin-turbocharged 3.0-liter straight-six engine, but it has not yet been certified for the upcoming Euro 7 emissions standards, set to take effect in mid-2025. There is also the B58 3.0 liter which already has the 48 volt mild-hybrid integration, and it’s used, successfully, across various M Performance BMW models.
From a business standpoint, the B58 could make sense, as it s widely used in models like the M240i, M340i, Z4 M40i, and Toyota Supra. A 48-volt mild-hybrid B58 would also be more cost-effective, but this decision could frustrate hardcore M enthusiasts. The last time BMW placed a non-M engine in an M car the N55 in the F87 M2 it sparked considerable debate, despite the engine s solid performance.
Choosing the B58 might make financial sense, but it could be seen as a step backward by purists. If BMW goes with the S58, they will need to ensure the engine is Euro 7-compliant, and luckily there is plenty of time to get the engine ready for a 2027-2028 M3 launch. Either way, BMW has a challenge on its hands as it balances emissions compliance with the expectations of M3 enthusiasts.
A Track-Ready Mild-Hybrid M3
One thing is certain though: BMW won t compromise on the M3 s track capabilities. If the B58 is selected, it will likely be a high-performance variant designed to withstand extended track times and deliver the sharp driving dynamics M cars are known for. The 48-volt mild-hybrid system will enhance performance, not water it down, ensuring the next M3 delivers on its reputation for being a true driver’s car.
With an expected power output of 530-560 horsepower, the mild-hybrid M3 will offer thrilling performance while meeting stricter emissions standards. The drivetrain won t match the output of the M5 s PHEV system, but it will provide the perfect balance between power and weight, keeping the M3 a true benchmark in its segment.
Luckily, BMW won’t go down the AMG route with a four-cylinder hybrid.
First published by https://www.bmwblog.com