How does a Dyno Really Work?

I REALLY started a controversy here when I claimed that there is "no such thing" as horsepower, and there isn't. HP is a myth, it is in fact a mathematical product, it s a "thing" that can NOT be measured. Dynos do not measure HP. They measure torque, and to calculate HP you need the torque figure as well as RPM or time and distance. Then you take those figures and plug them onto the HP formula, either with a computer or pencil and paper

I don't know how you could ever be accurate with an engine mount deal, because you would be fighting the chassis / engine interaction on bumps,etc, on the road/ track. And, you'd have to have some kind of radius figured out to actually measure torque, but it is an interesting idea.

Anybody ever heard of truck electromagnetic hill retarders? Someone actually made a dyno out of one. They look like very large disc rotors on the driveshaft, only they do not use brake shoes. They use huge strong electromagnets, to provide the braking action.

And of course actual brakes HAVE been used for dyno's but they would have to be fairly short term, to combat overheating and brake fade. All that torque has to be converted to SOMETHING!!! Either actual work, or heat!!!

Horsepower = Torque x RPM / 5,252