The performance of an engine directly depends on the amount of mixture that goes through / is burned and is transferred into mechanical energy per unit time.
To increase performance, there are 3 possibilities:
Which possibilities can be achieved following these physical ground rules?
Possibility A can only be done up to a point since the engine constructor has set most parameters.
Possibility B can not be done without making big changes and many long dyno tests.
Possiblitly C is the normal way to achieve this goal.
Possibility C gives another 3 options:
If a little is good, more is better, too much is perfect, Yankee saying)
What good is an engine that wakes up at 6000 rpm and dies off at 8000 rpm? Surely this is no fun during daily driving. And how are you going to get up the sidewalk at night without waking up the whole neighbourhood?
A usefull combination of all given options give a "smart" solution.
Here is a summation of options:
This includes most possibilities.