No, it's not. Doppelbauer is absolutely right. He just forget one key strategy with these high dynamic dynos. You make them longer, called cigar. The longer, the more area to apply the force. But then you've got a problem with the tyredyno design. The best cigars are 150cm's long, the ones used to test the best F1 engines. Those are handmade in low numbers, and extremely powerful and sensitive. They always need to need to know the exact absolute angle of the rotor, which is a hard mechanical problem. Wrong cooling fluid will break the engine. Only very few such engines do exist, but they are multitudes better than any cheap engine. Such dynos usually win F1 championships.

Yeah, it's a neat motor design, but it doesn't support the headline - 6% greater power to weight of the motor.