Audi S6 vs Nissan Altima: Specs Compared

Running cost over five years: at the EPA's 15,000-mile-a-year assumption the Nissan Altima burns about $1,900 of fuel annually against $3,450 for the Audi S6. That $1,550 yearly gap compounds to roughly $7,750 over five years and $12,400 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 Nissan Altima leads in both cycles — 28 mpg city and 39 mpg highway against 19 and 28 mpg — so its fuel-efficiency advantage holds whether you commute in traffic or cover long highway miles.

Powertrain choice: the Audi S6 is recorded with 2 distinct engine configurations (SIDI; Mild Hybrid, SIDI), the Nissan Altima with 4 (SIDI, SIDI & PFI, SIDI & PFI; VCR). Across 10 recorded Audi S6 configurations and 46 for the Nissan Altima, 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 Audi S6 is offered with All-Wheel Drive, 4-Wheel Drive, the Nissan Altima with All-Wheel Drive, Front-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 Midsize Cars and Midsize Cars respectively — the class drives the interior volume, cargo space and passenger space each one is measured against.

Tailpipe emissions: at their cleanest configurations the Nissan Altima emits 278 g/mile of CO2 versus 408 g/mile for the Audi S6. Emissions track fuel consumption almost exactly, so the cleaner vehicle here is also the cheaper one to fuel.