Audi S8 vs Bentley Flying Spur: Specs Compared

Running cost over five years: at the EPA's 15,000-mile-a-year assumption the Audi S8 burns about $3,800 of fuel annually against $4,000 for the Bentley Flying Spur. That $200 yearly gap compounds to roughly $1,000 over five years and $1,600 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 versus highway split: the Bentley Flying Spur is the stronger commuter at 17 mpg city, while the Audi S8 pulls ahead on the interstate at 27 mpg highway. If most of your driving is stop-and-go traffic the city figure is the one to weigh; for long-distance highway mileage the reverse is true, and the two vehicles effectively swap places depending on how you drive.

Powertrain choice: the Audi S8 is recorded with 2 distinct engine configurations (SIDI; Mild Hybrid, SIDI), the Bentley Flying Spur with 4 (SIDI; PHEV, SIDI, SIDI & PFI). Across 12 recorded Audi S8 configurations and 23 for the Bentley Flying Spur, 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 S8 is offered with All-Wheel Drive, the Bentley Flying Spur 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 Large 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 Bentley Flying Spur emits 161 g/mile of CO2 versus 452 g/mile for the Audi S8. Emissions track fuel consumption almost exactly, so the cleaner vehicle here is also the cheaper one to fuel.