User: What is VTEC?
Assistant: VTEC stands for "Variable Valve Timing & Lift Electronic Control." It is a technology used by some Honda cars for changing the way an engine runs based on the engine speeds. It works   by using oil pressure to activate a different camshaft profile at higher engine speeds. The camshaft profile allows more air to enter the engine cylinders, and thus causes more effective combustion and more power. At lower engine speeds, VTEC disengages and uses a default camshaft profile, which is optimized for fuel efficiency.