Water Additives

A dynamometer works best with clean, cold water at the inlet. This applies for the engine cooling system and absorber. For closed water systems, additional water treatment and lubrication may be required to maintain the quality of the water and extend the life of the system.

Test methods and supply water conditions affect the performance and life expectancy of a SuperFlow dynamometer system. As these methods and conditions vary per location, specific recommendations cannot be made. The following section gives only general observations on additives and their use.

The only way to determine what additives may be required is to have the water tested and analyzed for content. Expert advice is available from various suppliers, which you can find one by searching on “water treatment suppliers.” At no time should additives be put into a water system without first knowing why they are required or if they are needed at all.

Minimizing Freeze

Depending on the winter climate, antifreeze may be required to protect against dyno water supply freeze-up. Some antifreeze formulas will foam inside the absorber. Foaming can cause loss of water stability and subsequent loss of dyno control. This spells disaster for a test. Use antifreeze that has ingredients to reduce foaming in the absorber. Always follow the manufacturer’s guidelines on the container.

There are alternatives for freeze prevention. The best way of course is frequent dyno testing. That will keep the air circulating and warm. Other ways include:

  • Blowing warm air into the bottom of the tank during cold spells
  • Adding a small pump to circulate water from the bottom of the tank through a heater and back to the top of the tank

Both of these methods can use thermostat control for unattended maintenance. All that is required is to keep the water moving and temperature above or near freezing.

Minimizing Corrosion

When considering protection from corrosion, it is best to have the water analyzed first. Then have a treatment company advise on what’s appropriate considering the materials that are to be protected. In some case, the use of sacrificial anodes would be indicated or possibly other types of safeguards.

The absorber, sump tank and engine cooling tower on a SuperFlow SF902 is built of aluminum or bronzed aluminum where water is contacted. Copper lines are used along with brass and nickel-plated steel fittings on the stand. Other types of materials are used where it does not interact with water.

Water filters should be used on both the supply and return to reduce particles in the water supply. The filters must be cleaned or changed regularly.

Minimizing Fungus

Algae will sometimes grow in a large body of water such as a dyno supply tank. Although it is unnecessary to maintain the pH quality of a swimming pool, some control on algae should be administered. As with an additive, the water should first be tested to determine if there is an algae problem or a local authority contacted for advice. Sometimes, simple algae can be controlled by adding one gallon of chlorine bleach per 1,000 gallons of water.


The real benefit from water lubricants is in its surfactant properties. Basically, a lubricant reduces the surface tension of the water, allowing it to make better surface contact with the absorber and therefore, improve its ability to conduct heat from the metal surface into the liquid. This will help reduce the overall outlet water temperature.

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