Mazda’s RX heaven

TOKYO SHOW STOPPER

MICHAEL STAHL

Rotary engine makes surprise return as RX-Vision previews all-new sports car

THE RX-7 is back! Or at least all the elements necessary for a rotary-engined sports car revival, perhaps targeted for 2017 (the 50th anniversary of Mazda’s first rotary) or 2020 (the centenary of the company).

The embodiment of this promise is the RX-Vision concept, revealed at the Tokyo Motor Show by Mazda president Masamichi Kogai, who proudly proclaimed: “One day, the rotary will make a comeback.”

Design chief Ikuo Maeda’s gleaming GT-proportioned Vision was merely a fibreglass showpiece, lacking engine or running gear, but in meeting rooms behind the glitzy stand there was the palpable sense among design and engineering staff that Mazda’s rotary-powered RX sports car series had merely taken a step back with the end of the RX-8 so as to now leap farther.

Research and Development boss Kiyoshi Fujiwara admitted that the next-generation ‘SkyActiv-R’ engine – a development of the turbocharged direct-injection 1.6-litre two-rotor 16X, previewed in the 2007 Taiki concept – will soon begin real-world durability testing in several Mazda markets, including Australia.

Maeda – whose father designed the original RX-7 in the 1970s – penned the last RX-series car, the RX-8, which ceased production in 2012. Wheels’ 2003 COTY winner had been acclaimed for its userfriendly 2+2 interior, accessed via rear-hinged half-doors.

The RX-Vision suggests a dramatic move away from such practicality, with a dashboardto- axle proportion and overall dimensions that invite comparison with front-engined V12 GT coupes.

Maeda was quick to explain that these proportions were exaggerated for effect; it wasn’t designed to any particular platform or set of engineering hard-points. “A real one would be smaller, more sports car than GT,” he said. “Our aim is to build a pure sports car – pure, lightweight, coming from the previous RX-7.”

The man who adorned the RX-8 with signature rotor details let the RX-Vision’s shape do the talking.

Actual RX-7 cues are limited to the four-lamp tail-lights and subtle ‘telephone handset’ rear graphic that links them. Both were elements of the third-generation RX-7, his personal favourite.

On the motor show turntable, the RX-Vision’s surfacing was a visual feast (see the video at WheelsMag.com.au). Light forms a bridge joining front and rear

“It will be a sports car – pure, lightweight, coming from the RX-7” – Mazda design chief Ikuo Maeda

wheel arches, but then spills spectacularly through subtle curves on the door surfaces. It’s the optical equivalent of going flat through Eau Rouge.

“The first impression is very simple; it has to be,” Maeda grinned. “But once catching some of the light, you can see the reflection is going like a ‘Z’. That shows the emotion, the form of this car. That is a major focus.”

The platform for the RX-Vision and its production iteration remains a mystery; the fact that the concept’s 2700mm wheelbase is the same as the CX-5’s is merely coincidental.

Japanese media have reported that Mazda has approached suppliers to help evaluate a reardrive platform for launch in 2020.

Though said to be for a mid-class car (Mazda 6, CX-5), it would be thi T rem m th su dri Th strange to switch to rear-drive in mainstream models from cheaper, space-efficient front-drive.

It’s most likely the production car – quickly dubbed RX-9 by the world’s press – will have a dedicated platform. Fujiwara still rues the fact that the RX-8 shared its platform with the NC MX-5, which was “not an ideal situation” for either car.

Fujiwara ventured: “This kind of sports car cannot use a current passenger-car platform. The low height and lighter weight is required. We have to consider more clever solutions.”

Clever materials and techniques are definitely on the agenda.

In the absence of a big luxury flagship, Mazda’s RX-series cars have historically fulfilled the role as the company’s technology leaders. Just as the RX-8 introduced friction-welding to join steel and aluminium panels, the newgeneration coupe may have mixedmaterial construction that would include composite body panels.

Of greatest interest, however, is the rotary engine, which is unique to Mazda and a halo technology for the brand.

Fujiwara says the new 1.6-litre turbo SkyActiv-R, with a higher compression ratio than the 13B Renesis used in the RX-8, will be exclusive to a sports car. And it will have better performance at low revs: “Turbocharging is one of the big contributors for the future of the rotary engine [because it] has some weakness at low rpm, in terms of torque.”

A fundamental hurdle has been the placement of the spark plugs in the rotor housing. Due to the path of the rotor within the housing, the

spark plug electrode can’t intrude into the combustion area, as in a piston engine.

Fujiwara indicated that they had investigated HCCI (homogeneouscharge compression ignition), but along the way “found another system, that uses the normal ignition system. It can be suited for future HCCI, but this system can be utilised for rotary as a first step.”

Could it be laser ignition?

From the sound of it, the SkyActiv-R is viable.

“We have all the technical solutions on the rotary engine,” Fujiwara said. “But we need time to validate the quality issues – with actual prototype vehicle, with prototype engine, driving in the actual market like Australia, America, Europe. That kind of quality validation is needed for the rotary engine, because we had bad experience in the past.

“We will carefully and completely validate before the commercialisation decision. Step by step, that’s my process. At this moment I can’t say when. But soon.”