A standard 4-cylinder engine, where each cylinder displaces 500 CCs, would be called a "2.0 liter engine." An 8-cylinder engine arranged in a "V" pattern, where each cylinder displaces 500 CCs, would be called a "4.0 liter V-8." In this example, the 4.0 liter V-8 would be approximately twice as powerful as the 2.0 liter engine.
So, how does an engine builder increase power by increasing displacement? Well, as illustrated above, the two basic answers are (i) increase the size of the combustion chambers (bigger cylinders) and/or (ii) increase the number of cylinders. Simple enough! Of course, displacement is just one of the many processes to evaluate and optimize in your high performance engine.
The size of an engine, usually given in Liter or cubic centimeter measurements, refers to the displacement of the engine. In other words, how much air can be moved through engine in one full rotation of the crankshaft. It is possible to increase the air flow using a turbo or super charger. However, I usually don't recommend this. After market installations of these take a toll on the engine and various components and often cause engine damage. The only way to actually increase the size of your engine is to get a bigger engine.
〉 Answered on May 2nd, 2008 by Suzanne Grego, Technician at City of Philadelphia Fleet Management