Performance flywheels have been used for many years for increasing performance. From the earliest days of racing and street build-ups, the world's best engine builders have been installing flywheels to give their engines the needed edge. Not only will you see a dramatic increase in usable horsepower, but engine life can also be extended since there will be less stress on the crankshaft. To achieve the greatest increase in performance a flywheel must lower the moment of inertia characteristics of the engine. Put in simpler terms, we must reduce the amount of horsepower needed to turn the flywheel so that horsepower can be used to turn the wheels.