This is why carmakers have developed schemes to vary the cam profile as the engine speed changes.

This made use of softer cam profiles to produce a less powerful engine but with an even broader spread of torque.

The engine was more quiet than before, featuring a milder cam profile.

They feature two different cam profiles: a low/mid lift profile or a high lift profile.

One rocker follows the cam profile, while the other actuates the valve.

The base circle is the smallest circle that can be drawn to the cam profile.

The cam shaft is rotated and, according to the cam profile, the follower moves up and down.

This method uses two cam profiles, with an actuator to swap between the profiles (usually at a specific engine speed).

This included a more aggressive cam profile, a larger bore with a shortened stroke, a new, short skirt piston and titanium rather than steel valves.

There are also bigger valves, revised cam profiles and the inevitable remapping of the engine management.