CHICAGO – Unveiling its taut Ibuki concept car for the first time in North America at the auto show here, Mazda Motor Corp. serves notice the iconic MX-5 Miata is about to change – perhaps radically.

Most importantly, if the Ibuki really is a window into Mazda’s thinking for the first genuinely all-new Miata since its debut in 1989, then the beloved roadster’s general layout likely is to be improved.

The Ibuki borrows heavily from the new platform of the RX-8 sports car, and that means the entire engine and transmission fit behind the front-axle centerline, imparting the same front/midship balance of mass that makes the RX-8 such an enthusiastic-handling car.

Ibuki concept test bed for next-generation Miata development.

The Ibuki also flaunts radically compact front and rear overhangs to emphasize the agility a roadster is expected to impart. The Ibuki is more than a foot (30 cm) shorter, overall, than the current Miata, say Mazda engineers. The combined overhangs are more than 15 ins. (38 cm) shorter than Miata’s.

The Ibuki concept also promotes more use of lightweight materials than currently seen on the Miata. There is reinforced plastic for the hood, fenders and door outer panels. The engine cradle and driveshaft are carbon fiber and the wheels are magnesium alloy.

Another Ibuki innovation is an air-conditioning unit mounted behind the seats. Mazda engineers say this not only enables cooling for several distinct body areas for each occupant, but frees up more room to allow the engine to be moved further back from the front axle.

The Ibuki was first shown to the public at the Tokyo Motor Show in October.