Boosting Auto Performance: The ABCs of Horsepower
Guys are obsessed with gaining more power; and can you blame us? Power is bold. Power is sexy. Power can be directed towards any goal. When used along with wisdom and restraint, power can change the world for the better. Power is also fun, like the power you feel when you step on the gas pedal and feel your car or truck surge forward. It must be something like the rush Captain Kirk and crew will feel a couple centuries from now, when Scotty’s finely-tuned engines launch the Enterprise on another galactic adventure. Few if any of us will live to see those days, sadly. On the other hand, we can all add more power to our automobiles, even with our primitive 21st century technology. The first step in doing so is understanding a few basics about mechanics. PHOTOS: See More of the 2013 Ford Mustang Boss 302 Horsepower: What Is It?
For most of history, the strongest sources of power available to human beings were wind, flowing water, and, especially, horses. The big animals were state-of-the-art technology for thousands of years, especially draft breeds. So, when James Watt was trying to figure out how to measure the output of his new steam engine in the late 1700s, it only made sense to use the amount of work a horse could do in a given time as the standard.
Though stories of how the famed inventor came about his formula vary, he ended up deciding that one horsepower would equal 33,000 foot-pounds per minute. In practical terms, this is the same amount of power needed to lift 330 pounds in 60 seconds, which Watt guessed was the capacity of a full-grown horse. The measurement stuck, largely because people of the time used horses in their daily lives and understood how much labor they could do.
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Horsepower is used to this day to gauge an engine’s strength. It’s what you’re trying to boost when you say you want your vehicle to have more “oomph” or “get-up-and-go.” And it’s created in your engine’s cylinders, thanks to a series of controlled explosions that take place under the hood while you’re driving.
Your vehicle’s fuel system pumps a stream of gas and air into the cylinders, which is then compressed by a piston and ignited. Conventional gas engines use spark plugs to touch off the blast, while diesel motors accomplish this through the energy created by compression. This power is transferred to the transmission, which enables the auto to run efficiently at a wide variety of speeds. Finally it flows to the wheels themselves, and off you go to your destination.
Keep on Strokin’
Car engines do their work in four separate phases, or strokes. The most important of these is the power stroke (if this terminology gives you dirty thoughts, then that’s your problem, not mine). Here are all four, listed in the order in which they occur:
- The intake stroke, during which the fuel/air mix enters the cylinder.
- The compression stroke, during which the mixture is compressed.
- The power stroke, during which the mixture ignites and explodes, pushing the piston back.
- The exhaust stroke, during which the leftover gasses are expelled from the cylinder. The cycle then starts over.
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All of the ways in which you can boost your vehicle’s horsepower are related to these steps. Here are some examples:
- You can modify your engine so that it crams more fuel and air into the cylinders with each intake stroke. This makes for a bigger explosion.
- You can enhance the oxygen content and density of the air that flows into the engine, either by controlling its temperature or by enriching its mixture with nitrous oxide.
- You can make the work done in the fourth stroke more efficient by streamlining the exhaust process.
In the rest of this series we’ll discuss ways to accomplish each of these modifications. Some of them will be relatively inexpensive. Others could set you back a few mortgage payments. Each, however, will make your vehicle faster, more responsive, and just more fun all around. And those are all good things, especially to those of us who are mad for power. See you soon.
PHOTOS: See More of the 2014 Chevrolet Camaro Z/28
Photo Credit: Mecum Auctions