2.5 Litre Horizontally Opposed 16-valve turbocharged Boxer with dual AVCS
New generation Impreza WRX STI features an enhanced 2.5 litre Horizontally Opposed 16-valve turbocharged Boxer Engine with a dual Active Valve Control System (AVCS), producing an impressive 221 kW of power and 407 Nm of torque.
Substantial Torque improvement throughout the rev range translates into better response and linear acceleration, designed to exceed the expectations of the most demanding drivers.
The fine tuning of this high performance engine includes the use of intake and exhaust AVCS, increased intercooler efficiency and the new lower positioning of the upgraded 2.5 litre Boxer ‘flat’ design engine, resulting in a more powerful and balanced driving experience.
The potent new engine successfully meets stringent Step 4 emission regulations and achieves lower fuel consumption compared to the previous model.
Electronic Throttle Control (ETC) or "drive-by-wire" technology eliminates the traditional mechanical connection between the accelerator pedal and throttle. ETC provides instant throttle response in relation to driver input and the engine's operating parameters. This equates to a smoother more responsive throttle control and also helps to achieve better fuel economy.
The Dual Active Valve Control System (AVCS) offers variable valve timing control mechanisms on both intake and exhaust valves that work precisely to optimise the charging efficiency and clean combustion throughout the rev range. This improves both low to mid rev range torque, high rev range output and overall environmental performance.
The capacity of the intercooler on the new STI has been enlarged, improving the charging efficiency of intake air.
This mechanism generates a strong tumble inside the intake air stream to improve the air/fuel mixture under cold conditions resulting in cleaner exhaust gas emissions under cold start conditions.
This system injects fresh air into the exhaust port in cold conditions so that non-burnt gas can be re-burnt minimising hydro-carbon emission. It also helps activate the catalyst quickly.