Toyota Motor Corporation has developed Toyota New Global Architecture (TNGA) engine series to achieve both fun-to-drive dynamic performance and excellent fuel economy by further evolving the technology that was built in ESTEC (Economy with Superior Thermal Efficient Combustion) engine series. This paper describes the development of a new inline 4 cylinder 2.5L gasoline naturally aspirated engine that plays a role to unveil TNGA engine series. In order to achieve higher power performance with lower fuel consumption, the engine frame structure was renovated and the combustion speed was dramatically increased. As such, stroke-bore ratio and valve layout were optimized. Also, both flow coefficient and tumble ratio of intake port was improved by adopting laser cladded valve seat. Moreover, a commonised module enables similar combustion speed in the series of TNGA engines. In addition to the renovation of engine frame structure, several new technologies were adopted. The Atkinson cycle using new Electrical VVT and new combustion technology adopting new multi-hole type DI injector improved engine power and fuel economy and reduced exhaust gas emission. Variable cooling system that has electric water pump and Flow Shut Valve (FSV) improved fuel economy by reducing warm-up time and mechanical loss. Also, variable oil pump newly developed has significantly reduced friction losses. By implementing these new technologies, the new 2.5L gasoline naturally aspirated engine achieved over 40% thermal efficiency and over 150kW engine power that increased by 13% compared to the previous 2.5L gasoline engine.