VTEC is one of Honda's greatest inventions. Though an undisputed expert in turbocharging as evidenced by years of Formula-1 domination while Honda was active in the sport, Honda's engineers feels that turbocharging has disadvantages, primarily bad fuel economy, which made it not totally suitable for street use. At the same time, the advantages of working with smaller engines meant that smaller capacity engines with as high power output as possible (i.e. very high specific-output engines) are desirable for street engines. Vtec stands for Variable Valve Timing and lift Electronic Control. VTEC has many different types of engines. they come in DOHC Vtec, SOHC Vtec,-E, 3-stage Vtec, i-Vtec, K Series, R-Vtec, i-Vtec with variable cylinder management, i-Vtec, aVtec, and Vtec in motorcycles. All these different types have a different type of job and power they put out. All of the engines are 4 cylinders. At low RPM, the ecru uses the low lift profile, releasing the synchronized pin to disengage the central rocker arm. This allows the camshaft lobes to actuate only the outer rocker arms, opening the valves less to provide better fuel efficiency in low power. As the engine speed increases the ecu engages the switch to lock the central rocker arm into the second high lift profile. As the extenuated central cam shaft lobe depresses the central rocker arm, the valves open farther to allow additional fuel and air into the cylinder. additional air/fuel mixer inhaled by the motor provides a stronger combustion, which in turn increases power at the expense of higher fuel consumption. Do Vtec engines require extra maintenance? Yes, Vtec engines do require extra maintenance. If you want your engine at its top performance you have to keep it maintained regularly. You have to stay on top of its tune ups, check transmission oil, clean bay, and overall just keep on top of its check ups. The engine gives about 27 miles per gallon in the city, and about 34 on the highway. One of the only disadvantages is that, for being a 4 cylinder engine, it uses the expensive octane gasoline. One of the advantages that vtec gives over a standard engine is the addition of a second power curve created by the hi-cam lobes. a typical engine begins to lose power at the top of its rpm range, but a vtec engine is given a 2nd power curve increasing its ability to make power at higher rpms. Vtec usually "kicks in" at 3500 rpms. VTEC, the original Honda variable valve control system, originated from REV ,introduced on the CBR 400 in 1983 known as HYPER VTEC. In the regular four-stroke automobile engine, the intake and exhaust valves are actuated by lobes on a camshaft. The shape of
