Not better than a Kessler dyno. The best Formula 1 teams still use Kessler. You need the long axle to apply the power to. You never heard of them as they are

Not better than a Kessler dyno. The best Formula 1 teams still use Kessler. You need the long axle to apply the power to. You never heard of them as they are only producing 30 a year.