Elio Motors has updated the design and powertrain of its prototype, bringing the company one step closer to producing its three-wheeled concept vehicle.

The startup announced earlier this week that it has begun building the fifth prototype, the P5, of its autocycle. The slim, low-profiled vehicle is officially categorized as a motorcycle on three wheels. It also has airbags, controls and a reinforced cabin like an automobile.

The key difference between the P5 and its predecessor, which was on display last spring at the New York International Auto Show, is the engine. Elio Motors said that its latest version will feature the company’s exclusive purpose-built 0.9 liter, 3-cylinder engine, which is paired with a manual transmission from Aisin.

Elio Motors

Paul Elio stands in front of the Elio Motors P4 at the 2015 New York International Auto Show

“The engine and transmission are key elements in creating driving characteristics that consumers demand,” said founder, namesake and CEO Paul Elio. “Fuel economy is obviously important, but we still need speed and acceleration that are comparable to today’s passenger vehicles. Both the engine and transmission put us well on this path.”

Elio Motors opted to develop its own engine when it wasn’t able to locate an option already on the market. The engine will be powered by gasoline, with a projected 84 mpg. The company estimated that the P5 will have a top speed of 107 mph and will be capable of sprinting from 0-60 in 9.6 seconds.

“The P5 build is another important step in our march toward production and is the culmination of several important strategic initiatives we have completed or launched in the past several months,” said Paul Elio, founder and CEO of Elio Motors. “The completion of our engine prototype, our offering to accredited investors and our recent supplier summit are all excellent examples of the progress we continue to make every day.”

SEE ALSO: Elio Motors Developing Its Own New Three-Cylinder Engine

The P5 most likely won’t be the final production-ready version either, with the company planning another 26 prototypes for “a variety of testing and validation purposes.”

Even though the design is still in development, along with the company’s proprietary engine, Elio Motors still anticipates that the vehicle will be ready to launch mid 2016 with a retail price near $6,800.

More than 43,000 reservations have been received for the autocycle, which will be sold using a system similar to Tesla Motor’s factory-direct sales method.