If engineers get it wrong, the belt will be noisy or rob the engine of power. For technicians, the job is even tougher.
These naturally aspirated, DOHC engines are found in Mustang GT, Mustang Boss 302 and F150 models.
Andrew Markel discusses belt noise and flutter, and how to inspect the belt, pulleys and tensioners for these issues.
On an engineering level, the design of the accessory belt drive is a balancing act of efficiency, force and vibration. The more contact or wrap a belt has with a pulley, the more force or energy can be transmitted without slipping and the less tension the belt will need. But, this is not great for efficiency because it creates more friction and drag.