Join Date: Jan 2008
The DynaPack (hub dyno) generally reads a bit higher torque & HP because the inertial load of tire & wheel is removed. They do have excellent control for tuning and you never have to worry about "launching" a car off the dyno if straps break.
Dynojet, Superflow, Dyno Dynamics, and Mustang all use rollers of differing sizes and they all work off the inertial acceleration methodology. All have loading capability for tuning and are much quicker to set up on the dyno since you don't have to remove wheels and consequently worry about retorquing them. You get the real "rear wheel HP" for your car since it is exactly how you drive it on the street.
Traction on the inertial dynos can be an issue on very high torque & HP cars as they tend to "blow the tires off the dyno" but you *can* place load in/on the car to compensate in most cases.