Threats come no more thinly veiled than this: By christening its new mid-size sport sedan an M45, Infiniti is warning all the world, especially BMW, that it means business. Under neatly chiseled skin, the upstart M borrows heavily from the slightly schizophrenic Q. But thoughtful recalibrations and a diet that hikes the power-to-weight ratio a healthy six percent make this a very interesting contender which every sport sedan competitor would be wise to take seriously.
Nissan's three-year-old LFR (large, front-engined, rear-drive) platform underpins both the M and the Q. A lusty 32-valve, 4.5-liter V-8 engine and five-speed automatic transmission serve both admirably. Sophisticated touches include variable intake-valve timing, variable-length intake runners, electronic throttle control (a.k.a. drive-by-wire), a hydraulically driven cooling fan, and a dual-mode muffler. While the Q's Electronic Torque-Demand system is programmed for supremely smooth delivery, the more impetuous M kicks its heels during gear changes. To boost the vitality of both upper-crust Infinitis, the final-drive ratio has been changed from 2.76:1 to a more lively 3.13:1.
Chassis blueprints are unchanged except for a 2.8-inch wheelbase snip, yielding 110.2 inches axle to axle, a mere 1.2 inches shorter than the corresponding dimension of the BMW 5-series.... Read full article