The revamped CX-9, a three-row family SUV, is kitted out with the new four-cylinder 2.5-litre engine equipped with what Mazda calls its "Dynamic Pressure Turbo."
The unit is said to provide strong response even from low RPM. It also eliminates the typical delay between mashing the throttle and feeling the rush of torque from a turbocharged engine.
To reduce lag, Mazda's engine gets its air via two paths. At low speeds, a valve closes the larger one and sends the air to the turbine through a narrower path.
This increases the pressure in the same way that happens when somebody steps on a garden hose pipe, says Mazda engineer Jochen Muenzinger. The result is that the turbo starts to spool earlier, opening the valve and supplying more power from low revs.
Mazda has also added a cooled gas re-circulation system, which uses some of the inert exhaust gas produced by the engine to reduce the temperature and feed it back into the air intake.
According to Mazda, the set-up virtually eliminates turbo lag and means that the engine develops as much power as a conventional V6 combustion engine with 3.7 litres of displacement.
The CX-9 engine is also 20 per cent more efficient, reducing fuel consumption and potentially harmful tailpipe emissions.
