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Uploaded on Jul 5, 2007
The DOHC i-VTEC system (one of the two cams shown). Found in the Honda/Acura K series, F20C and F22C1 engines, the i-VTEC system uses roller rockers, continuously variable intake cam timing (VTC, not shown) and three separate cam profiles for both the intake and exhaust valves of each cylinder. These features improve power and efficiency of the engine across its entire rpm range.
Below 5,800 rpm the offset and low lift of the valves aids in fuel atomization. This provides improved low end torque and fuel efficiency by creating a powerful swirl in the cylinder and by keeping the intake air charge at high velocity. Above 5,800 rpm a high lift, long duration cam profile is engaged by the synchronizing pistons to provide greatly improved high rpm power and torque.