VTEC for example, is a cam changing system that utilizes multiple cam lobes on either one or two camshafts. VTEC shifts between a low cam profile and an high cam profile setting based on rpm. This system does improve peak power, and can raise red line (up to 9,000 rpm in S2000), just like an engine with racing camshafts, and increase power from 10-25%. However, the VTEC engine must rev at or above it's threshold rpm to really get things cooking. VTEC is used on Honda and Acura engines.

VANOS and VVT are used by BMW, Toyota, and various other car manufacturers. These systems allow earlier or later valve opening through cam phasing. The camgear changes the phase (or position) of the camshaft based on engine load, and is controlled by engine management system according to need, and actuated by hydraulic valve gears. At high speed for example, the inlet camshaft could be rotated in advance by 30 degrees or so to enable earlier intake opening. Unlike VTEC, these types of systems come closer to infinite variable timing, since they do not rely on changing cam lobes to vary timing.