Infiniti QX50 vs Subaru Ascent: Specs Compared

Running cost over five years: at the EPA's 15,000-mile-a-year assumption the Subaru Ascent burns about $2,650 of fuel annually against $2,800 for the Infiniti QX50. That $150 yearly gap compounds to roughly $750 over five years and $1,200 over eight — often more than the price difference between two trims of the same vehicle, and the single largest running-cost line item separating these two.

City and highway economy: the Infiniti QX50 leads in both cycles — 24 mpg city and 31 mpg highway against 21 and 27 mpg — so its fuel-efficiency advantage holds whether you commute in traffic or cover long highway miles.

Powertrain choice: the Infiniti QX50 is recorded with 3 distinct engine configurations (SIDI & PFI, SIDI & PFI; VCR, 3.7), the Subaru Ascent with 1 (SIDI). Across 20 recorded Infiniti QX50 configurations and 18 for the Subaru Ascent, the wider the engine spread the more the real-world fuel efficiency depends on which version you actually buy, so check the specific model year and drivetrain rather than the headline number.

Drivetrain and class: the Infiniti QX50 is offered with Front-Wheel Drive, All-Wheel Drive, Rear-Wheel Drive, the Subaru Ascent with All-Wheel Drive. All-wheel drive typically costs one to two mpg combined against the same vehicle in front- or rear-wheel drive, which is worth remembering when the gap between these two is small. The EPA classes them as Small Sport Utility Vehicle 2WD and Standard Sport Utility Vehicle 4WD respectively — the class drives the interior volume, cargo space and passenger space each one is measured against.

Tailpipe emissions: at their cleanest configurations the Infiniti QX50 emits 336 g/mile of CO2 versus 384 g/mile for the Subaru Ascent. Emissions track fuel consumption almost exactly, so the cleaner vehicle here is also the cheaper one to fuel.