BMW's latest engine dubbed the N55 is a
twin scroll single turbo engine which boasts
306HP and
400Nm of torque out of a 3.0 litre inline 6 cylinder engine. Sound familiar? Yup this is a similar amount of power from the N54 of 335i/135i fame, but now using the new twin-scroll technology BMW can achieve this power from the use of only one turbo.
This is not simply a more efficient engine, but it achieves the similar amount of power with quicker throttle response and max power lower in the rev range (1200rpm).
What is twin-scroll?
Dual side by side exhaust inlets feed into a single housing in this setup. Because there are now two exhaust inlets being fed into the housing the exhaust channel can be smaller given more precise control of the velocity of air flow.
Valvetronic -- finally
Yes valvetronic is back in BMW engines again, due to technical reasons the engineers weren't able to use valvetronic correctly with the N54 but have finally overcome whatever obstacles were in their way and now it returns to the N55 with direct injection.
This engine is making its debut on the 535i GT but as in BMW fashion will likely filter down the range and take its place in the 135i, 335i, 535i, 735i, etc..
Quote:
BMW’s current N54 series straight-six engine is one of the most praised engines in the industry today, having taken out the coveted International Engine of the Year award last year and appearing in a vast array of BMW models. With the unveiling of the new 5-series GT last week, BMW has announced a new variation of the 3.0L engine which will debut in the crossover at the end of the year.
The N54 features a twin-turbocharging system, as well as direct-fuel injection and BMW’s own Valvetronic technology, and in its most potent configuration develops up to 326hp (243kW) at 5,800rpm and 332lb-ft (450Nm) of torque from as low as 1,500rpm. BMW’s new variation on the engine, labeled the N55, is based on the same basic engine block and valve system but only sports a single turbocharger. It is the world’s first engine to combine turbocharging, direct fuel injection and fully variable Valvetronic valve management developed by BMW.
Peak output is still a healthy 306hp (225kW) at 5,800rpm and 295lb-ft (400Nm) of torque from an even lower 1,200rpm. Furthermore, the new N55 is also said to be more fuel-efficient than the N54 though no independent test results have been produced.
As previously mentioned, the N55 engine will debut in the 535i 5-series GT along with an eight-speed automatic transmission. This model will be able to accelerate from 0-100km/h in around 6.3 seconds and is rated at 26mpg (9L/100km) in fuel economy.
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http://www.motorauthority.com/bmw-un...series-gt.html