From the back seats of our 2015 Bentley Mulsanne Speed, we sipped champagne through rush-hour traffic in Miami - I still don’t know if it was legal or not in Florida, but the chauffeur assured us it would be fine.

A frosted door between the back seats hides a wine fridge and pair of champagne flutes designed specially for Bentley. The cup holders, you see, will hold one of these champagne flutes but probably not, say, a Big Gulp from 7-Eleven.

The Mulsanne Speed—Bentley’s new flagship—is certainly about the details. But details are a given in this rarefied strata of the automotive world. The real magic of the Bentley is something more difficult to discern.

The supersonic age

The Florida Keys look like Venice, if it was taken over by American developers in the ‘70s and then left to fade. The scenery is pale and sun-washed but the people a burnt and deeply tanned.

From a private island, a ship drops us off at someone’s house on the Keys. His garage holds a small airplane. The backyard is a runway, shared apparently among neighbors.

Before we can take in this absurdity, we board a helicopter to nowhere. With a top speed of around 320 km/h it would’ve been a close race between it and the Mulsanne Speed.

The pilot radios the tower at a secret airport in the middle of the Everglades. A single, perfect, 10,500 ft (3.2 km) runway comes into view. It was to be the world’s largest airport, a hub for supersonic air-travel. That was 1968. Then the oil crisis hit and only 14 Concords made it into the skies. The project was scrapped, but a lone runway remains.

2015 Bentley Mulsanne Speed (photo: Bentley)

Takeoff

The “six-and-three-quarter-litre V8” engine as Bentley refers to it has been in development for 45 years. This latest version is twin-turbochaged, and efficient enough to run off the dirty exhaust fumes of the original.

But this car isn’t about fuel economy. Its official EU ratings of 22.8 L/100 km city and 9.9 highway make that clear.

The Speed gets modest power and torque bumps over the Mulsanne Signature, as well as tweaked steering for better feel. The result is effortless power: 530 horsepower and 811 lb-ft of torque. The motor doesn’t rev, it churns. The redline starts at just 4,500 rpm.

What does all that torque feel like? About right, actually.

Line it up with the flying “B” on the nose pointing straight down the centerline of the 3.2-kilometre long runway. Left foot on the brake, right foot hard down on the gas, sidestep the brake and the rear-wheel drive Mulsanne fires itself down the tarmac with no drama. The huge rear tires hook up quickly. But with 811 lb-ft of twist going through them, the Bentley engineers say they are near the limit—any more torque and the rims would spin in the tires.

The engine makes only a deep, muted gargle. It sounds like an old wooden speedboat. Acceleration is calm: 0-100 in 4.9; 0-160 in 11.0. The cabin remains quiet until around 140 km/h when wind noise starts to filter in. At 250 km/h it’s time to gently roll on the brakes. They do an admirable job of arresting this 2,685 kg machine. But it’s not something you’d want to put the car through often.

2015 Bentley Mulsanne Speed (photo: Bentley)

A small excerpt from the option list on our test car

Options (all figures USD): entertainment spec ($28,760); refrigerated bottle cooler and crystal champagne flutes ($10,970); dark stained Vavona wood trim ($5,015); deep pile Wilton overmats ($1,445); flying “B” radiator mascot ($3,330); etc. Base price: $335,600. Total options: $67,615. Total price: $403,215.

In Canadian dollars, the Mulsanne Speed starts at $406,120 or $38,000 more than the Mulsanne Signature. It will arrive in the first quarter of 2015.

Landing

The Bentley glides over the roughest roads, even riding as it does on 21-inch rims. The outside world is inaudible. The steering is light and accurate. You tend not to think about accelerating or braking, it just happens as you guide the car down the road.

The mirror reflection off the Mulsanne’s long hood shows the rest of the city living upside-down.

As nice as sipping champagne through rush-hour was, the place to be in the Mulsanne is the driver’s chair. Objectively, everything about the car is exceptional. Subjectively, it just feels right.

2015 Bentley Mulsanne Speed (photo: Bentley)