So I am aware of the existence of high specific output engines like in the Honda S2000 or Ferraris, but one common criticism those cars tend to have is their lack of torque. Why does it seem so difficult for these engines to make more torque as well?
In: Engineering
Although you can measure the horsepower of an engine, when you see horsepower stats for vehicles they are never measuring that. Rather, they’re measuring how much force can be used to spin the wheels when the car is in its highest gear at the engine’s optimal RPM. Because that’s how horsepower is measured in the real world, it makes more sense to think of torque as a measure of the raw power of the engine and horsepower as a measure of how efficiently the transmission can convert that power into work.
High performance cars tend to weigh as little as possible because weight is the biggest cost constraint in attaining good acceleration, top speed, and handling. IE, if Car A weights twice as much as Car B, it will cost a lot more to make Car A perform the same as Car B on a racetrack. So if you have a $150k budget for your new Ferrari, the way you make that Ferrari go as fast as possible is to make it as light as possible.
The two biggest sources of weight in a car are the engine and transmission. The more torque an engine produces, the heavier both it and its transmission have to be to survive the forces being applied to them. But like I said, weight is expensive and the goal of high performance cars is to weigh as little as possible. This means that you want the lightest possible engine and transmission for the performance that you can obtain.
The way that sports cars do this is by having *relatively* low powered engines (at least compared to heavier cars like trucks) that produce power through the use of a complex transmission that has a large number of gears. Adding more gears doesn’t add any more weight, but it does allow you to have a much higher gear ratio in the highest gear. That higher gear ratio allows you to very efficiently convert the engine’s torque into work when the car is already travelling at high speeds, producing more horsepower than the engine otherwise would with fewer gears.
This isn’t to say that a Ferrari doesn’t have a powerful engine – a typical Ferrari has an engine that produces about as much torque as the engine in an F-150. But when you start to get into more mid-range sports cars, like the Porsche Boxster, you also start to get engines that are producing 2/3 as much torque as a typical truck.
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