Mazda: Bigger engines are better than turbos

It's true, there really is no replacement for displacement.

Mazda's head of research and development, Kiyoshi Fujiwara, believes real world fuel economy testing will spell the end of smaller capacity turbocharged engines, instead favouring bigger capacity, naturally-aspirated powerplants.

Fujiwara made the claim despite Mazda just introducing its first turbocharged Skyactiv petrol engine, the 2.5-litre unit in the new CX-9; which replaced a 3.7-litre V6. Asked if the new turbo engine would be used in other models, including the new CX-5 and Mazda6, Fujiwara revealed why he believes the days of small turbo engines are numbered.

"I cannot say the specific topics for the turbocharger systems but at last most of the European manufacturers have started to speak [about] downsizing to right-sizing or downsizing to up-sizing," he explained. "That was announced by us five years ago, people say 'downsizing is the trend' or 'downsizing is the way to go' but we said no. Now it is completely changing, therefore our turbocharger system will become less important for future technology. But some of the engines require turbocharging."

Mazda has focused its resources on developing its Skyactiv range of naturally-aspirated petrol engines - 1.5-, 2.0- and 2.5-litres. With the company now in a stronger financial position, with no debt, Fujiwara wants to develop a new larger engine.

"I know inline four-cylinder turbo engines can replace V6, therefore CX-9 engine is quite suited to that technology," he said.

"But if we have some money, enough to invest in more cylinders, more cylinders are suited for the future technology. Future emission gas controls are much severe because real world [tests] are required, which means more wide range of capability is needed for reduced emissions. Therefore in that case more cylinders or bigger size or up-sizing displacement is suited to all of the models. It is just now the trend is downsizing but for the future we know what technology needs to be done."

He added: "Bigger displacement is much better for us for future severe real world emissions [testing]. Probably 3.0-litre or 4.0-litre is too much for four-cylinder engine, so more cylinders are required. A bigger displacement engine is better for us, for the future."

However, Fujiwara stopped short of confirming a new, larger engine was under development.

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