This is what you'll find inside the DTS absorption unit. The large bronze impeller is connected to the engine via a driveshaft, and it literally pumps water in the housing to measure torque. Horsepower is actually derived mathematically from the torque reading.
Before The Dyno Test
Of course, the greatest advantage of a dyno test is that it can provide a roadmap to making more power, if you know how to find it. One of the key elements here has less to do with equipment than with personnel. An experienced and knowledgeable dyno operator will add immeasurably to the value of a test, and the operator will usually be the point man when it comes to finding that "magic tune." Experience plays a key role here-remember, you are paying for the operator's time as well as for the time on the machine. It is worthwhile to make some inquiries both at the shop and within the local performance community to get an insight into the facility being considered for a test. A skilled operator will be an asset in evaluating the data from the dyno and making interpretations that can lead to improved performance. Just as importantly, a skilled operator will often detect and head-off problems before they develop into serious trouble and help find faults if they occur.
DTS' control station is self-contained, and comes with a layout that is compact and easy for the operator to use. Here, Dan Roberts from DTS is at the controls of one of the two in-house test cells qualifying a new dyno before it is shipped out to a customer. Each dyno is rigorously inspected and tested.
Preparing for a dyno test should begin with a conversation with the dyno operator. It's important that everyone is clear on what the objectives and goals of the test will be, and that everything required is identified ahead of time. Besides discussing the basic engine combination, it is important to be clear about what additional testing you'd like to accomplish. You'll need to know what components in addition to the engine assembly will be required for testing, which will vary from shop to shop. You may need to supply a set of headers, though in some cases the shop will have dedicated dyno headers, often set up to accept exhaust gas temperature probes. The dyno may be equipped with an ignition system, or you may elect to run the system that will be used in the car. It's important to discuss the requirements and capabilities of the shop to run ancillary equipment, such as nitrous, blowers, or a dry sump. Find out what equipment and supplies the shop has on hand before showing up on test day. Things to consider include:
The DTS docking carts mate with the chassis of the dyno unit and are attached with quick-connect latches. The system saves time in setting up the engine, so that more time can be devoted to testing.
Prelube adapter
Carburetor
Fuel lines (especially for multi-carb induction)
Headers
Mufflers
Ignition system
Fuel pump
Sparkplug wires
Flywheel
Oil and Filters
Fuel
Tuning Parts (jets, sparkplugs, etc.)
Gaskets
Special tools
Testing is the right way to finish any engine build. Besides identifying potential problems, the test will almost always unleash hidden horsepower and efficiency after dialing it in on the dyno. Here Speed-O-Motive's Jake Harriston is setting the final valve lash on a big Mopar stroker after running it in on the dyno.
Testing an engine provides the opportunity to try a variety of equipment and the dyno results can provide the basis for component selection, based on the results. You might wonder, is a 1 7/8-inch header an advantage over a 1 3/4-inch set? Is a 750-cfm carb the best, or would an 850 prove better? Single-plane or dual-plane intake? The dyno will help answer these kinds of questions for your particular engine combination. Just be sure to discuss the testing ahead of time, so that the operator can provide some insight on what can be accomplished in the allotted time, and how the test will be structured to make the best use of that time. Don't expect to show up on test day and surprise the operator with 12 intake manifolds. Explain to the shop what you'd like to test and work out a plan to get that testing accomplished. You'll need to consider what additional items will be required to get the parts swapping done, such as gaskets and sealants, fasteners, or special tools the shop may or may not have. Communication here is vital to a successful day on the dyno. It's good practice to prepare a checklist of what you'll need to bring.