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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.

Have questions about SuperFlow engine dynos? Want to speak to a representative about SuperFlow dynamometer systems?

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Useful Flowbench Tools

Many of the applications of flowbenches and the data they provide are often set apart from normal data because of the mystique associated with flowbenches and flow testing. Engine component airflow data is easy to compare if you know how. Here are tools we recommend using to make the job of testing airflow easier and much more fun than makeshift approaches.

Magic Wand

It provides an indication of activity and direction of flow inside a port or device under test. The magic wand is made from a 1/16” diameter welding rod that is 12” long. The welding rod has a small round ball on the end – from placing the road in a molten pool of metal – and a piece of dacron or nylon type kite string glued to itself to form a little flag about 3/8” long. This is a good flow visualization indicator.

Pilot Tube

It provides a way to probe the port to supply local velocity numbers. It can be used with SuperFlow’s FlowCom, pressure manometer, or special port software to plot areas of activity in the airstream in a port. It’s difficult to use in very small ports. It requires one type for exhaust use and a different one for intake use.

Flow Ball

It provides a method to probe a port and verify if flow is attached or separated at some point in the port. Flow balls are made by tack welding various diameters of ball bearings to a 1/16” diameter welding rod that 12” long. Flow balls typically start with 1/8” diameter and go to ½” diameter in 1/16” increments. These tools are an easy way to find problem areas in the port without great difficulty. It’s very effective in evaluating the short-turn radius in a port of where a wall has a directional change.

Port Molding Rubber

It provides an easy way to look at a port. The mold is made of silicone-based material (a two-part process) that is poured into the port with value in place. After it sets, it can be removed in one piece. The mold can be sliced and the cross-sectional profile drawn on graph paper to help measure the area at different locations in the port.

Graph Paper

This creates an easy way to measure the cross-sectional area in a port. The paper cutouts are trimmed to fit different places in the port, and the squares can be counted, providing an accurate way of measuring the area.

Poster Board

This creates an easy way to make patterns to help the developer reproduce the same port shape and size. The poster board can then be used to trace patterns in aluminum or plastic that provides benchmarks for the developer to use in duplicating an established shape in other ports and cylinder heads of the same type.

Radius Inlet Guide

It provides a smooth approach to the port or device being tested and is intended to decrease the “edge effect” at the port flange. The radius used should be as large as possible and at least ½” radius. The thickness of the inlet guide should be at least 50% of the height of the port. The size outside the port cross section should also be least 50% of the height of the port so all directions have a smooth approach. It is not uncommon for the inlet guide to improve the flow from 6% to 10% over no guide in use.

Exhaust Pipe

All testing of the exhaust side of the cylinder head should use a short section of exhaust pipe that is at least the diameter of the port. The appropriate length is about 10” to 12” long.

Bore Simulation Adapter

All flow testing of cylinder heads should use an adapter that simulates the bore size within 1/16” of the diameter used on the engine. The length of the simulated bore should be at least equal to the diameter or more.

Wet Flow Adapters

It provides another reference of flow visualization that is valuable in evaluating what is happening in the combustion chamber and helps to sort out problems in that area. It’s best when at an air/liquid ratio that represents the normal air/fuel ratio an engine uses. This process has helped solve problems that would otherwise go unnoticed.


Ever present at any testing is a flow tester on the phone comparing numbers with another tester. It provides an instant indication of hype vs. truth because known numbers are compared to claims.

These are basic tools you need on hand for airflow testing, which will provide incredibly insightful and helpful information.

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