Revving up the Horsepower with Dynamometers

by Rebekah Fuller, IQS Editor

Rebekah Fuller Author Pic

Car enthusiasts and manufacturers alike are quite familiar with the term dynamometers, referring to systems that measure the torque and horsepower of an engine. I, on the other hand, just hope my car continues to have enough get-up-and-go to get me where I need to go. Until my work with industrial manufacturers, I don’t even remember encountering the word dynamometer. If you are having trouble pronouncing this mouthful, don’t worry, it’s commonly shortened to dyno. To impress real car buffs just ask about the most awesome dyno demonstration they’ve ever seen. Don’t be surprised to hear about the sweet horsepower a certain vehicle’s motor was able to produce. With dyno testing being done not only by top vehicle manufacturers but also at car shows, in the shop and garages, it is easy to see how the process can go from a highly controlled evaluation for improved performance and safety to a spectacle of supercharged speedsters.

Dynamometers Procedure

Photo courtesy of Sakor Technologies, Inc.

You have to be careful and watch your step around dynamometers in motion. I’ve watched enough YouTube videos of mishaps around these motor testers to know. Accidents include fires and explosions caused by valve cap leaks, blown o-rings, unsafe nitrous use or any other way to push the engine beyond capacity until it blows. I also saw someone trip and fall on his face while walking around a car that was hooked up to a dynamometer, and even a car jump the testing apparatus and dangerously barrel toward the edge of an elevated stage in a Car Craft Summer Nationals dyno accident.

Motor Testing

Photo courtesy of Sakor Technologies, Inc.

Respect must be given not only to the powerful motors being tested, but also the dynamometer being used, as it is an integrated system of equipment and software utilized to measure a combination of torque (rotational force), horsepower, maximum rotary speed and maximum power absorption to give a clear picture of a motor’s total output, capacity and performance. Professionals are able to determine with careful testing and analysis what adjustments need to be made to better an engine. They would certainly know to strap the car down as much as necessary to properly secure it based on expected output, and not to sit in the car’s trunk to keep it in place, which I did see some guys doing.

Chassis Dynamometers

Photo courtesy of Sakor Technologies, Inc.

You can’t just expect the wheel chocks to hold the car in place when using chassis dynamometers that measure torque at the wheels. In this kind of system the vehicle should remain stationary as the wheels turn on rollers, though you can expect some rocking as the motor runs. Other systems called engine dynamometers test just the engine by itself apart from the body of a vehicle. Dyno results vary in accuracy; some can have a margin of error that is less than one percent. Chassis dynamometers are usually 15 to 20 percent lower in their measurements because some energy is lost as it travels through the drivetrain. The RPM of the rollers allows a computer to calculate the torque of the engine. In an engine dyno, contact and/or non-contact sensors are used to transmit signals from the motor’s wiring and/or mechanical parts like the rotor and shaft to, ultimately, the dyno operator. The force of the torque is transformed into an electrical signal that is amplified, converted and displayed as a measurement. As horsepower has to do with load amount related to distance and time, motors can be tested from no load to a full load capacity, and hydraulic dynamometers can be employed to increase the load. Brake dynamometers can also take measurements by applying variable loads to the engine and observing how the engine maintains the RPM as the braking force attempts to slow it down.

Hydraulic Dynamometer Brake Dynamometer

Photos courtesy of Sakor Technologies, Inc.

Today’s dynamometers in a variety of models and variations decrease human error and offer faster more accurate measurements for many motor applications, not just automotive, and dynamometer manufacturers offer complete, turn-key systems for performance, durability and quality control testing of electric motors, starters, alternators, generators, HVAC systems, pumps, transmissions and much more, even emissions certification testing. Humans are still in control of how safely the equipment is used, so make sure the horsepower does not exceed the capacity of the dynamometer, and I’d keep a fire extinguisher and even a first-aid kit handy just in case!


Photo courtesy of Sakor Technologies, Inc.

VN:F [1.9.10_1130]
Rating: 5.0/5 (2 votes cast)
Revving up the Horsepower with Dynamometers, 12.5 out of 5 based on 2 ratings
This entry was posted in Plant & Facility Equipment and tagged , , , , , , , , , , . Bookmark the permalink.

Comments are closed.