The very modern combustion engine can be altered to add horsepower or torque by manipulating the size or length of the connecting rod and enhancing the bore or diameter of the cylinder. This is usually referred to as the bore/stroke ratio.
Torque is often measured in Newton meters. In simple terms, this implies that torque is measured in a 260-degree circular motion. Our example takes two identical motors about the same sized bore (or the diameter of the combustion cylinder). However, one of the two motors has a longer “stroke” (or the depth of the cylinder as generated by a longer connecting rod). The motor with the longer stroke has more straight motion while it spins through the combustion chamber and has more leverage to complete the same task.
Torque is often measured in pound-feet or how much “twisting force” is applied to finish a task. For example, think of yourself trying to loosen a rusty bolt. Let’s assume you have two different pipe wrenches, one is 2′ long, the other is 1′ long. Assuming you apply the same amount of force (in this case 50 pounds of pressure) you are basically applying 100 foot pounds of torque for the two foot wrench (50 x 2) and only 50 lbs. of torque (1 x 50) with the one foot wrench. Which wrench will assist you loosen the bolt easier? The answer is easy – it is the one with more torque.
Engineers develop an engine to generate a higher torque to horsepower ratio for cars that require the extra “power” for acceleration or for climbing. Ideally, you see higher torque ratings for heavy duty trucks used for towing applications or high performance engines where acceleration is vital (such as the NHRA Top Fuel Engine example noted above).
That is why automotive manufacturers usually highlight the high torque potential of engines in truck commercials. Engine torque can equally be amplified by replacing ignition timing, adjusting air to fuel mixtures, and even manipulated to add torque output during some scenarios.