What is VTEC and how does it work?
The following is excerpted from Lee Cao’s excellent webpages. ” Taking a single cylinder as an example, it has intake valves to breath in the fuel/air mixture, and exhaust valves to channel away the combusted exaust. How much the valves open and for how long they stay open is controlled by cam shafts which have roughly eliptical shaped lobes that actuate the valves. How wide the valves open is referred to as valve lift. When and for how long the valves stay open is referred to as valve timing. To oversimply things a little bit, valves that open wider and stay open for longer durations allow greater amounts of fuel and air to flow through the cylinder. Therefore, building an engine that has good high RPM power require that the valves must open wider and hold their opening for longer durations. However, valve lift and timing that are optimised for high RPM performance usually leads to rougher low RPM combustion, resulting in an idle that becomes increasingly difficult to maintain. Honda’
