BorgWarner’s new, world’s first regulated two-stage (R2S) turbocharging system with four turbochargers for passenger cars has debuted in the BMW Group’s latest TwinPower Turbo diesel engine, available for different high-performance models.

While a conventional R2S system features one turbocharger for the low- and high-pressure stage respectively, this unique application utilises two turbochargers for each stage. It thus provides higher efficiency, which contributes to constant and fluid power delivery over the entire rev band, and helps improve fuel efficiency up to 4 percent compared with the engine’s predecessor.

“BorgWarner’s latest and most sophisticated R2S system features four turbochargers to take boosting to a whole new level and help our customer achieve the highest demands for power and efficiency for an exciting driving experience,” said Frédéric Lissalde, president and general manager, BorgWarner Turbo Systems.

“We introduced our R2S turbocharging solution into the passenger car market in cooperation with the BMW Group and are pleased to take the next step together. This prestigious project helps reinforce our position as a market leader in turbocharging technologies,” Lissalde added.

Featuring four turbochargers, BorgWarner’s advanced two-stage turbocharging system boosts the new 3.0-litre, 6-cylinder, inline diesel engine to achieve a power output of 294 kW (394 hp) and a maximum torque of 760 Nm. To meet these high requirements and provide outstanding performance, BorgWarner replaced the low-pressure turbocharger with two smaller ones to reduce inertia for faster response without increasing system weight. At low engine speeds, one high-pressure turbocharger quickly generates boost pressure for rapid acceleration without any noticeable turbo lag. At higher flow rates, both high-pressure turbines operate to increase the capacity.