Two years after revealing a prototype, and four years after beginning development, the UK's Elemental Motor Company is putting the final touches on its high-performance roadster ahead of a 2016 Goodwood Festival of Speed reveal. Since we last looked at it, the Rp1 roadster has gotten more power and a more optimized construction, promising an outright exhilarating ride on track and road.

When we last looked in on the Rp1 at the 2014 Goodwood Festival of Speed, Elemental was fully committed to making an ultra-lightweight, simple car to maximize the effectiveness of the 280-hp 2.0-liter EcoBoost engine. The focus on low weight hasn't changed, but the engine specs have. Elemental plans to offer the production Rp1 with two mid-mounted options: a 180-hp 1.0-liter three-cylinder EcoBoost and a 320-hp 2.0-liter four-cylinder EcoBoost. Those engines work with a six-speed sequential gearbox with electro-pneumatic shifting.

If you skim through Elemental's press materials quickly, you might think there's a third, 500-hp option, but the 500-hp figure represents the hp-per-tonne ratio, so that's 1 hp per 2 kg, calculating into a weight of 1,411-lb (640-kg). Elemental's website suggests that weight can drop as low as 1,191 lb (540 kg) with the 1.0-liter engine and 1,279 lb (580 kg) with the 2.0-liter.

That low weight helps the 320-hp engine in powering the Rp1 to 60 mph (96.5 km/h) in 2.8 seconds and 100 mph (161 km/h) in 6.4 seconds, with the 180-hp variant hitting those marks in 3.2 and 7.8 seconds. Top speeds are listed at 145 mph (233 km/h) for the 1.0-liter engine and 165 mph (266 km/h) for the 2.0. All numbers are estimates, and Elemental is still completing testing.

Critical to the Rp1's feathery light build is the 143-lb (65-kg) CarbonAl tub chassis, which has been improved over the prototype version. It features an F1 prototype-style feet-up driving position and was designed to exceed FIA strength and rigidity standards.

"The feet-up driving position puts the Rp1 at the forefront of its sector as it provides space to accommodate a diffuser under the front half of the car as part of the cutting edge aerodynamics package," explains Mark Fowler, Elemental co-founder and aerodynamics and bodywork lead.

According to Elemental's modeling, the Rp1 road set-up is capable of generating 882 lb (400 kg) of downforce at 150 mph (241 mph). The company is still testing the more track-focused set-up and expects to see that figure increase.

The production Rp1 maintains the previously discussed focus on driver adjustability. The suspension can be adjusted with basic tools, or even by hand, letting the driver tweak things just right for the specific ride ahead. The Rp1 rides on front and rear dual wishbones. Up to five available traction control and engine mapping settings can be switched through, letting the Rp1 run the spectrum from basic, open-top road cruising to full-blown race day performance.

Elemental will show the production-ready Rp1 at the Goodwood Festival of Speed later this month, running one in the Hillclimb and displaying another at its booth.

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