BMW has announced its latest generation 7-Series flagship sedan is to gain a range of new powertrains through 2016. The most potent of these is the replacement for the ‘N57’-designated tri-turbo engine, which will debut in the 750d and 750Ld xDrive models.
The highly-praised N57 engine consisted of single large diameter, low-pressure turbocharger working in unison with two smaller high-pressure ones to ensure an equal spread of torque and power across the cars rev range.
The all-new B57 unit replaces the singular large-diameter unit with two smaller ones, on the same exhaust manifold. This new packaging approach has improved efficiency, with BMW claiming a marked improvement in consumption, as well as lower CO2 emissions. Despite this, the maximum output for the engine has increased to now 400hp, and maximum torque of 760Nm, making it the most powerful diesel engine ever used in a BMW model.
The 760Nm is produced between 2,000 and 3,000rpm and is transferred via ZF’s ubiquitous 8HP eight-speed automatic transmission.
In addition to the new diesel, BMW is also introducing new ‘iPerformance’ models, in the form of the 740E and 740Le iPerformance versions. The plug-in hybrids garner technologies from the development of the i3 and i8 models. Despite producing a combined 326hp, the hybrid is able to travel over 45km in pure electric mode.
The CO2 emissions is quoted as being as low as 50 to 45g/km for the 740E iPerformance and just 56-49g/km for the all-wheel-drive BMW xDrive 740Le iPerformance.