Hub Dyno Test Cell Facility

Our dynamometer which is manufactured by Dynapack™ direct couples to the wheel hubs and applies a precisely controlled hydraulic load. This method of direct coupling plus its built-in strength means the Dynapack™ is always in control of the vehicle.

Controlling a powerful car on a roller dyno can sometimes be a daunting task. With Dynapack™ you have TOTAL CONTROL of the vehicle, with no wheel slip due to its direct coupled design. With that there is less inertia to mask the results, giving you greatly improved sensitivity, repeatability and significantly reduced time spent tuning and mapping!

With the power of the Dynapack™ literally at your fingertips, you have complete control over the test and the demands placed on the vehicle. Flexible data presentation and analysis is available direct from the Dynapack™ in seconds.

How is the dynapack different?

THE MOST OBVIOUS DIFFERENCE IS THE ELIMINATION OF THE TYRE TO ROLLER INTERFACE THAT EXISTS WITH A CONVENTIONAL ROLLER DYNO.
The Dynapack™ eliminates this variable by using a hub adapter that provides a direct coupling to the Power Absorption Units. There can be no tyre slip, no rolling resistance, and no chance of the vehicle coming off of the dyno at high speeds. Notice that we call this a variable. Sometimes it may be a problem area, other times it may not. Tyre temperature, pressure, traction, etc, are all variables that can change – not only from run to run, but during the run as well.

Throw an unknown variable like this into the equation and your data has now become subject to a potentially high margin of error. It is obviously better if these variables could be eliminated – which is exactly what we have. There are other associated problems with the roller method as well. Take tie-down straps for example, most roller dyno’s use ratcheting tie-down straps to attempt to hold the vehicle in position while being tested. If the straps are cinched down tightly, the tyre has becomes loaded even further, in an unpredictable manner.

While this may be good for enhancing traction, it changes the rolling resistance of the tyre – skewing the data further. Since these tie-down straps aren’t perfect, the vehicle squirms around on the rollers – dramatically changing the tyre drag during the run. If the vehicle is tested in two different sessions, the straps can’t be set exactly the same way twice in a row. Again, the data will be inconsistent.

We have heard of cases where the ratcheting tie-down straps were loosened by two clicks and the measured power increased by ten horsepower. What if the straps stretch – either from run to run, or during the run itself? Wouldn’t it be great if all of these problems could disappear? With a Dynapack™, they were never there in the first place.

ANOTHER MAJOR DIFFERENCE IS THE EFFECT OF INERTIA.

Street wheels and tyres spinning at high RPM have a large amount of inertia. A large steel drum spinning at the same ground speed has much more inertia. What you end up with is a giant, heavy flywheel attached to your engine. The inertia is such that just trying to accelerate the mass of the roller is a substantial load for the engine. That is the principle that some roller dyno’s (or inertia dyno’s as they are also called) operate on. Accelerate a known mass to a measured speed over a given time and it can be calculated to equal a certain amount of power. There is nothing wrong with this theory, but like many theories, its application in the real world can be troublesome.

How do you think your measurements will be effected when subjected to this large heavy flywheel phenomenon? Will small fluctuations be noticeable? In a word, no, the flywheel effect tends to take small rapid variations and smooth them right out – as energy that should be going into the dyno is being wasted trying to accelerate a large lump of steel.