Sierra Research Dynamometer Tester

The Sierra Research Dynamometer Tester (SRDT) is an ingenious new instrument for determining the road-simulation accuracy of chassis dynamometers. It was developed as a collaborative project by Sierra Research Inc., of Sacramento, CA and Real Time Dynamometers.

The SRDT is portable and easy-to-use. A carrying case holds all the components, which include the laptop computer, printer, electronic control box, and sensor cables. The system is truly portable, in that it does not even require 115 VAC power to operate (it uses the laptop's own batteries and the batteries in the electronic control box).

How does it work?

  1. Using the laptop, the operator enters dynamometer and vehicle data.
  2. The accuracy of the force signal is confirmed by the dead-weight method.
  3. The frictional loss profile of the dynamometer is determined.
  4. The vehicle is installed on the dynamometer and driven. To begin and end data logging, the operator clicks "Start Sampling" and then "Stop Sampling."
  5. The results of the test, including a plot of the data, are printed out.
  6. Datafiles (may include roll speed, acceleration, expected power, achieved power, power error, vehicle tractive force, force from the force sensor, and parasitic loss data). are saved on the laptop hard drive.

The SRDT can test dynamometers capable of simulating full inertia (both positive and negative) as well as those capable of simulating only positive inertia (e.g., those with eddy-current power absorbers). Click here to view Tester specifications.

A new version of the Sierra Research Dynamometer Tester will be applicable to 4WD dynamometers (having two independent speed and force signals).

Please contact us or Michael St. Denis ( with any questions about the Sierra Research Dynamometer Tester.