Having run hundreds of tests on the. effect of 2-valve throttle body upgrades on everything from stock to supercharged combinations. (both centrifugal and positive displacement), it is safe to say that throttle body upgrades on the 2-. valve motors are a worthwhile endeavor.
VDC may refer to: In technology: Virtual design and construction, modeling software and techniques to design and evaluate possible construction processes; Volts of direct current; Video display controller, a computer graphics chip; Vehicle Dynamics Control, a means of increasing vehicle stability through a combination of throttle restriction and braking
So VDC power doesn't mean anything by itself, but, say, 12 VDC power means power that is supplied at 12 volts DC. (It's more correct according to some style guides to write V DC instead of VDC, but VDC is common in industry.) If you want to talk about DC power, but you don't want to specify a voltage, just say DC power..