/Source:Automotive News/ The next-generation rotary engine from Mazda Motors isn't ready. The engine, unveiled at the 2007 Tokyo show under the code name 16X, was planned as the power plant for the next-generation RX-8 sports car to be launched in 2012.

Seita Kanai, head of Mazda research and development, said the engine does not meet the performance and fuel economy guidelines the automaker requires for a production model and it continues to work continues to cut the rotary's fuel consumption.

The code name refers to the increase in the current engine's displacement, from 1.3 liters to 1.6 liters.

Kanai declined to say whether it's back to the drawing board for the 16X. "The 16X is more a profile of a rotary still in our concept stage," he said. "It needs more evolution."