Parr can offer full chassis and engine dynamometer facilities in a controlled environment test cell. The 800 Bhp Dyno cell allows Parr to accurately measure the performance of your car without external influences affecting the data.
Parr wanted a system that was as accurate and flexible as possible and after looking into all the options only one solution was acceptable a hub mounted system. With this system the hub of the vehicle is directly attached to a hydraulic absorption unit.
We can apply a variable but precise load – all the way up to a hydraulic lock if we needed to. Simultaneously we are monitoring load and measuring the hub RPM, so we can determine the amount of work being performed. It sounds easy until you realise that all of these calculations are very complex and are happening very quickly.
Add to this, all of the data logging functions and real-time full-colour graphics that are also being calculated, and you begin to realize that what appears to be simple is actually very complex.
We have total control of the axle. Literally. Want to hold a steady RPM? We can hold an axle RPM (within 3 rpm) for a stable engine at any power level – all the way up to the rated maximum torque capacity of the Dyno for as long a period of time as you'd like. If the software allowed it, we could stop the engine within one revolution of the crankshaft.
The first and most obvious difference is the elimination of the tyre to roller interface on a conventional roller Dyno. The hub-mounted system eliminates this variable by using a hub adapter that provides direct coupling to the Power Absorption Units. There can be no tyre slip, no rolling resistance, and no chance of the vehicle coming off the rollers at high speeds. Notice that we call this a variable. Sometimes it may be a problem area, other times it may not. Tyre temperature, tyre pressure, tyre 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 this can be eliminated. What you end up with on a roller 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.
How do you think your measurements will be affected by being subjected to this large heavy flywheel phenomenon?
In a word, no. The flywheel effect tends to take small rapid fluctuations and smooth them right out. This is great if you want your power curve to look like a smooth pretty line, but it doesn't give you much insight into what is really occurring.
What if you eliminated the flywheel effect? Whilst every spinning mass has some inertia, when compared to the total mass of the wheels, tyres, rollers, and other associated hardware in a roller Dyno, the inertia in the hub-mounted system is practically zero.
This allows us to precisely measure and display tiny rapid pulses and oddities that you may not have ever seen before.
Another benefit of having virtually zero inertia is the ability to change the rate of acceleration at will. In many simulations, you may want to make the vehicle accelerate at a different rate to simulate a specific condition. With a few simple keystrokes, we can allow the vehicle to accelerate very quickly, very slowly, or anywhere you'd like in between.
Because of the lack of inertia and the total control we have over the axle speed, we give you choices. Our runs are repeatable to within three-tenths of one percent!
Parr will of course be developing all performance products on the Dyno and can offer customers the following services: