The Pagani Huayra Roadster BC is the most powerful Pagani roadster ever, and it was conceived by accident.

In 2016, Pagani introduced a more hardcore version of the Huayra supercar wearing the initials BC. The Huayra BC was available only as a coupe, but customers soon began putting down deposits for an open-top version, even though Pagani hadn't announced one. The company decided to give those customers what they wanted, founder Horacio Pagani explained in a recent video detailing development of the Roadster BC.

The car follows the same recipe as the Huayra BC hardtop, a combination of more power and less weight. Use of composite materials such as Pagani's patented Carbo-Titanium and Carbo-Triax make the BC 66 pounds lighter than a standard Huayra Roadster. Dry weight is 2,755 pounds, or about the same as a Ford Fiesta, Francesco Perini, concept, composite, and mechanical design manager at Pagani, said in the video.

Pagani Huayra Roadster BC

Pagani Huayra Roadster BC

The Roadster BC has much more power than any Fiesta, though. The engine is the familiar 6.0-liter twin-turbocharged V-12 sourced from Mercedes-AMG, producing in this application 790 horsepower and 774 pound-feet of torque.

The V-12 is coupled to a 7-speed automated manual transmission from Xtrac that can shift gears in just 75 milliseconds. That's twice as quick as the gearbox in the standard Huayra Roadster, according to Pagani.

As with other Huayra variants, the Roadster BC is covered in spoilers and flaps to generate maximum downforce. Pagani also added new underbody flaps to this latest model. The Roadster BC can generate up to 1,100 pounds of downforce at 174 mph, according to Pagani.

Pagani Huayra Roadster BC

Pagani Huayra Roadster BC

Pricing starts at $3.4 million and production is limited to 40 cars. That's twice the number of Huayra BC coupes Pagani built, but it's unlikely that any build slots remain open.

Pagani is working on a Huayra replacement. Codenamed C10; it's expected to arrive in 2021. The traditional Mercedes-AMG V-12 will return initially, but Pagani is also working on a battery-electric version.

Note, the Huayra Roadster BC may not remain Pagani's most powerful roadster for long. The company has just unveiled an 827-hp Huayra Imola track car, and we wouldn't be surprised if a roadster version showed up as well at some point.