Ford has completely redesigned the softtop on its new Mustang as the automaker prepares to take on Audi, Mercedes-Benz and BMW convertibles in global markets including Europe.The top on the 2015 Ford Mustang convertible will open in 7 to 10 seconds, roughly twice as fast as the 2014 Mustang. That way, drivers won’t have to wait as long to get sunshine and fresh air. When the top is up, a new layer of insulation between the cloth layers will make the interior quieter and the exterior more streamlined.

When the top is in the down position, the stack will be 170mm (6.7 inches) lower than on the current top. The more compact stack will make the open-air car more aerodynamic. And the new mechanism will not intrude into the trunk as much as the old one, which gives the new Mustang convertible 19 percent more cargo space than the current car.

Steve Ling, Mustang marketing manager, said the convertible accounts for 18 percent of Mustang sales: “It’s a good piece of business as we look to take the Mustang global.”

Ready for the autobahn

The top isn’t the only place where its new global profile will affect the 2015 Mustang, arriving later this year. On Wednesday, Ford took journalists inside the wind tunnel to show how they’ve engineered the 2015 car for global roads, including German autobahns.

“With the new Mustang, we spent about twice as much time running aerodynamic simulations and doing wind tunnel tests than the previous Mustang,” said Carl Widmann, aerodynamics engineering manager. For this demonstration, Ford used the hardtop, fastback version of the car. Until now, Mustangs have been designed primarily for America. The 2015 model is the first designed specifically to be sold around the world.

“This needs to go 155 mph on the German autobahn with BMWs and Porsches,” said Kemal Curic, Mustang exterior design manager. “We had a pretty good car, but we needed a little more. That’s why we spent all the hours in the wind tunnel to get the downforce of a world-class sports car.”

The Mustang is the first Ford to be equipped with front-wheel aero curtains to guide air across the front wheels. Rotating wheels are a source of drag on a moving car. Ford designed the new Mustang with vertical slots at the outer edges of the front fascia to channel air from the front of the car through openings in the wheel wells and across the outer surface of the wheels and tires, reducing drag, Ford engineers explained.

One version of the Mustang, powered by the new 2.3-liter, four-cylinder EcoBoost, will get active grille shutters, which close the grille off and send air over the top of the car at higher speeds.

Wednesday’s technical briefing on the convertible and on aerodynamics was the first of several monthly technical briefings Ford is holding before the Mustang goes on sale this fall.