Subaru - Impreza WRX STI

Technology

The Subaru Boxer Horizontally-Opposed 2.0 litre turbocharged engine has been a Subaru hallmark that we have refined with each new model year. The unit that powers the WRX STi is the ultimate expression of this development because our mission is to make it the finest of its type in the world. The process is typified by the use of hollow intake and sodium filled exhaust valves, which reduce inertia and friction for high revving reliability and smoothness. Allied to lightweight shimless valve lifters and Subaru's varible valve timing system, they help to make the engine more responsive and willing over the widest possible rev range.