How it works: four-valve versus two-valve engines

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Your engine is composed of many moving parts and pieces. In order to move through the four stages of internal combustion, all of these bits and bobs are quite necessary.

Some engines, however, take advantage of squeezing in a few more parts where they can.

One area where this is seen often is in extra intake and exhaust valves. Why does it matter if you have double the valve count, and how does it work?

Engineering Explained is here with answers, and it all boils down to math.

That math is fairly easy once you see it written out. We'll boil it down even further for you, though.

MORE: See more car-tech videos

What you're doing when you increase the number of valves per cylinder is increasing the open area.

When intake valves open, they take in a given amount of air. One large intake valve cannot suck in the amount that two smaller valves can handle.

The same goes for the exhaust valves that let gas out. When two smaller exhaust valves are stacked up against a single large valve, the bigger bit will lose out in efficiency and responsiveness.

More valves equal better airflow and a more efficient engine. Smaller valves are lighter, which means the engine can rev higher, create more power, and in general, look down upon the two-valve engines of the world with a sense of multi-valve satisfaction.

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