The 3.0-liter N55 six in the 2011 BMW 535i uses one twin-scroll turbocharger, plus direct injection to get an easily verifiable 300 horsepower and 300 pound-feet of torque. Not only does our 535i feel great, it puts up the same acceleration numbers as the V8-equipped BMW 540i of a decade ago.
The Audi's 3.0-liter V6 engine has more low-end grunt, though, if you don't mind its industrial drone. Response is sharp off the line, and then it delivers a torque curve as broad as Montana. You don't expect performance like this from a V6 (forced induction or not) and neither do the motorists you've just blown by on the freeway.
What's more, the Audi's supercharged V6 is listed at 310 hp and 325 lb-ft of torque, but we suspect it's even more underrated than BMW's turbo inline-6s. Why? Its quarter-mile time is a half-second quicker and its trap speed was 102 mph, 5 mph faster than the 535i. The A6 is also half a second quicker to 60 mph at 5.2 seconds (or 4.9 with 1 foot of rollout like on a drag strip).
Eight Speeds for All
Both sedans use the ZF eight-speed automatic transmission (though you could order a six-speed manual on the 2011 535i). Forward gearing is nearly identical, but the sedans' final drives are different, and of course, each manufacturer uses it own proprietary software.
In their respective sport modes, both automatics upshift smoothly under full throttle and downshift with authority, not to mention matching revs to keep things smooth. In Manual mode, the A6 upshifts for you before the rev limiter, which is more of a poetic injustice than a real problem when you have an engine that's all about the midrange.
The 535i is plagued by the same sluggish response to part-throttle inputs we've observed in a few other BMWs like our long-term 528i, our long-term 750i and the 2011 740i. It's hard to be smooth in city traffic, so we hope BMW will address this soon.
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