N54 vs. N55? Or in non-geeky words, twin-turbo vs. twin-scroll engine? Car and Driver gets behind the wheel of a 2011 BMW 335i and shares their impression of the new engine compared to the N54.
Before we jump into the article, here is a bit of history on the new engine. N55 is a turbocharged straight-6 automobile engine. It was launched in early 2009 in the new BMW 5-Series Gran Turismo in the BMW 535i GT model. It is BMW’s first production single turbocharged gasoline engine that combines the use of Valvetronic, turbocharger technology and direct injection technology.
The preceding N54 was a twin-turbocharged straight-6 that did not use Valvetronic.
How Does It Drive?
Nearly identically to the N54-powered 335i: It’s fast, smooth, and extremely stable. With the announcement of the move to the single-turbo engine, enthusiasts (including us) cried foul. We believed the N54’s output had been underrated and that the N55, although matching it in advertised output, would be weaker in reality.
But all of that can be put to bed. Our 2011 335i was just as quick as the twin-turbo car, reaching 60 mph in the same sprightly 4.8 seconds. The quarter-mile flew by in 13.6 seconds at 106 mph, 0.1 second behind the quickest twin-turbo sedan we tested. After the century mark, however, the new mill picks up steam, reaching 140 mph nearly a full second quicker.”