Short and simple, VTEC solves the problem you often ran into when driving for example a Toyota Camry from the early 90's Great midrange, but after 5000 RPM it fell flat on it's face. VTEC allows you ot tune the engine tooperate well at low RPM's and good economy yet have good high RPM peak power when needed. It gives you the desirable flat torque curve that all engine builders strive for.