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How Engines Create Power Cars convert gasoline into motion by way of combustion, which takes place internally inside an engine. The physics are pretty straightforward: Put a tiny amount of high-energy fuel (gasoline) inside a small enclosed space, and ignite it to release an incredible amount of energy in the form of the expanding gas. The foundation of many engines is the engine block, which contains pistons that slide up and down. The pistons are housed inside cylinders. The more cylinders an engine has, the more powerful it is. A V6 or V8 engine refers to the configuration (V) and number (6 or 8) of cylinders. Race cars generally have V8 engines, meaning eight cylinders to house the powerful pistons. The engine also has a combustion chamber, and that is where air, fuel, pressure, and electricity come together to create the small explosion that moves the pistons up and down. That movement creates the power to move the car. NASCAR engines have larger intake valves that allow more air into the engine, particularly at higher

speeds. A device called a carburetor lets in large volumes of both fuel and air. However, NASCAR has several rules that limit speed. Pistons work like this: the intake valve opens, and the piston moves down, allowing the engine to take in a full cylinder of the air/gasoline mixture. The composition is mostly air because very little gasoline is needed. As the piston moves up, the air/fuel

A V8 engine typically has four cylinders on each side of the engine block.

mixture is compressed to create the powerful explosion that actually propels the car forward. The pistons move in a linear motion that is then converted into rotational motion, courtesy of the crankshaft.

CHAPTER 1 : SPEED

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