If you’re looking to have a dyno that simulates track loading, you’ll need an adjustable load source. All of the above are great reference for the use of an inertia dyno (or water brake) at a fixed ratio (i.e. fixed load). To simulate what an engine will see on the track will require the use of a fine adjustment. This can be done in a variety of methods:
– closed loop variable frequency drive on a std AC induction motor (will need a brake resistor to handle the regenerative energy)
– a true AC servo drive (again – will need a brake resistor to handle the regenerative load)
– a proportional relief valve if using water or hydraulics (insure you have enough fluid capacity to handle the effects of heat rise)
A small programmable controller that monitors axle speed of the dyno and engine speed should be able to give a command signal to the drive(s) or valve in proportion to engine speed. It will take a little while to map the command signal to the engine speed, but it’s all very easily done. Once you figure out what the command signals(offsets) need to be, you can adjust when the fine adjustments are made during a pull.