There are three engines in the Q70's line-up; a 2.2-litre turbodiesel four cylinder, a 3.5-litre V6 hybrid powertrain and a 3.7-litre petrol V6. The hybrid model's petrol motor kicks out 302bhp with an additional 67bhp electric motor, while the diesel produces 168bhp and the flagship V6 develops 315bhp.
Having switched from a six-cylinder diesel to a four and been downgraded by almost 30 percent on both power and torque, it was inevitable that the Q70 would feel somewhat impoverished here. The car’s saving grace may yet prove to have been the unpopularity of the M30d, because the new blood buying the Q70 for its fleet viability probably won’t have known what the old M-series offered, so they won’t miss it.
Whether you’re inclined to judge this car against its immediate predecessor or its immediate rivals, our performance numbers betray it as not only sluggish but also only average for fuel economy.
Even if you mitigate the car’s leisurely step-off by winding up the torque converter, the Q70 diesel takes 9.6sec to pass 60mph from standing.
The chilly conditions of our test day can have made little difference to the Q70’s performance, because it barely has enough power to make wheelspin a factor.
And although our True MPG real-world fuel economy testers have recently seen almost 49mpg from the most frugal versions of the A6 and Mercedes-Benz E-Class on a like-for-like combined cycle test, the Q70 returned only 39.0mpg.
In day-to-day use, the Q70 may not feel as disappointing as those objective numbers may imply, but it fails to do much that gives it the distinguishing aura of a true premium product. Although reasonably quiet at low revs, that Daimler diesel sounds and feels coarse both on start-up and when working hard. Infiniti claims to have Active Noise Control at work in the cabin, cancelling the harshest frequencies of that motor through the car’s audio speakers.
If that’s true, you wouldn’t know it once the crank is spinning beyond 3000rpm, when the engine becomes abrasive as well as increasingly breathless. And although the seven-speed transmission shifts smoothly enough in laid-back mode, it won’t be hurried to kick down, or by selecting a lower ratio using manual mode.