Actually on an inertial dyno torque is measured and horsepower is calculated. It's calculated by the time it takes to accelerate the mass (roller) over time. Again look at the way horsepower is calculated, it's work done over time.

Now I have seen a lot of dyno sheets both chassis dyno from Mustang the eddy current to the Superflow inertial. Every time I have had a run come out weird, either I or the guy running the dyno said it was a bad run and we ran it again and threw out that run because it wasn't correct. Personally I haven't had an issue picking up spark, but I have been turn d away because the dyno was not able to pick up ignition rpm because of one reason or another. As far as being "real world" unless dyno manufacturers have sat on their hands for more than 10 years and haven't improved their products, or people are using equipment that is not fit for proper measurement then everything should be spot on. I work in the weights and measures industry. I manufacture in-motion scales we weigh most everything you have ever come in contact with, be it food, concrete, C4 (yes the explosive kind), salt (table, rock and water softener), Bacon.... Basically the list is endless. Now the scale industry (among others) is heavily regulated by Weights and Measures. I don't recall seeing anything on dynos (octane and fuel, yes) but I'll check and see if there are any NIST standards for them but I don't think they are covered. Most of this looks like sloppy work of the operator. To me if someone tells you some stuff about phase of the moon or some overly complicated explaination they are not dazzling you with brilliance, they are baffling you with BS.

One instance of a company doing a half ass job of making a piece of machinery is some of the golfball dispensers. We had a company come to us to be able to fill golfball a into a bag based on weight. Well that's a problem since not every one weighs the same. We decided counting them would be better since that's what they were going for anyway. None of the manufacturers were able to hold a very good tolerance +/- 2-3 balls per fill. We said we could do 99%.

If you go into Walmart or Academy and are into golf chances are you have bought a bag or bucket of used balls under the Reload or Hunter name or any other used golfballs, they were done on the filler we designed. We are able to fill anywhere from 12-100 balls per package with 99.8% accuracy over the last 5 years in operation.

Now if our company can make a machine that we have no experience in counting golfballs at high speed. Why can't a dyno manufacturer get their crap together? I don't think it's the dyno I think it has more to do with the operator.

The math vs real world doesn't fly anymore. They may not be exact, but they will be within a couple of percent, if not something is wrong.

Jeff