86BillionFireflies t1_iuhjyuj wrote on October 31, 2022 at 11:52 AM

Reply to comment by Silvster88 in ELI5: How exactly do we get some much power from engine now, than we did 40, 50, 60 years ago? by Micromashington

This is a sort of minor point, but just to make it clear what you're saying, it might help to define what you mean by power. At the end of your comment you draw a distinction between horsepower and power, so I'm assuming that when you say power, you're not using "power" in the physics sense of the word (amount of work done per unit of time, measured in Watts), since HP is a unit of power (one HP = around 750 Watts). I think, from the body of your comment, that by "power" you mean torque at low RPM, or maybe the minimum amount of torque available across the entire RPM range.

I'm not trying to disagree with anything you're saying (I'm nowhere near knowledgeable enough), just pointing out that the terminology used by people with automotive expertise may differ from the terminology commonly used in other areas (sciences, some fields of engineering) in a way that causes some confusion.

I'm also curious, what would you say is the reason why cars with lots of low-RPM torque were so popular? How much do factors like being able to produce very high HP or large amounts of torque actually affect people who just drive their cars to work / the grocery store?

Silvster88 t1_iuhlmoi wrote on October 31, 2022 at 12:09 PM

So power was used intentionally because of the point I’m making as it’s a broad term referring to the capabilities of an engine. Realistically the only thing we measure on a vehicle to determine it’s “power” levels is torque. Torque is the amount force the engine produces. Horsepower isn’t a thing measured but a formula. Horsepower=Torque*RPM/5252. So when I say “power” Im referring to the amount of force an engine can put out without a specific measurement.

Why were cars back then so interested in low end torque has multiple reasons. The first reason is because it’s just a matter of design. The bigger the engine the higher the inherent torque. If you look at naturally aspirated engines there is a typical trend that larger engines have bigger more torque. It’s just physics at that point.

The other reason is because it’s more enjoyable to drive. There’s not a lot of places you can go to crack open that horsepower and push the car up to 150+mph. By prioritizing low end torque you get that super quick acceleration while not having to push the vehicle to unsafe speeds.