I was reading a recent issue of Racecar Engineering and there is a picture of a car on a Dynapak chassis dyno. The interesting thing is that it doesn't use rollers in the ground, like a Dynojet. It's a big box that sits on the ground. The car is parked next to it, jacked up, and the drive wheel is removed. Then a big rod connects the hub to a hub on the dyno. This removes the wheels and tires from the equation, and would provide more accurate results, I suppose. I just wondered if anybody had experience with this sort of dyno.