ECU Remapping – Dyno Test before you tune

So, in your pursuit of trying to attain additional horsepower and torque in your new build you have taken many steps. You may have tweaked system specs or maybe you have replaced several stock parts to aftermarket parts in order to increase performance. Sure it feels and sounds like a dream, but really how much power did you gain? Was it worth all the time and money you just sunk into your car? Don’t you wish there was a way to visually see the difference? Well, there is a way and it is called a dyno test.

This article will explain what a dyno test is and how you can benefit from putting your vehicle under one.

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How Does a Dyno Test Work?

All performance engines should be run through a dyno test. This is especially true for racing engines. A dyno test promotes correct engine break-in measures and will make it easier for you to spot any potential issues such as leaks or valve train problems. Doing so before you run your engine hard will give you the ability to correct these issues before they become serious or create other concerns.

A good amount of quality engine builders will insist on a dyno test in order to certify the quality of their work. Many times you will even see that independent builders will take the time to bring their engines to a qualified shop for a dyno test to check and validate their work. This is because the dyno test is a invaluable tool to use when it is implemented correctly.

Insights on the Dyno Test

  • You should always keep in mind that your engine is quite sophisticated at logging input data. Thus, it is only as accurate as the data that was used to program it. In order for it to operate at its peak, it must be under the most accurate atmospheric and engines specs.
  • Also keep in mind that when using a dyno test to check your engine, you should always use the same one in order to ensure accuracy. Changing from one dyno to another will not allow you to properly compare numbers because of the many variables.
  • Finally, do not wear out the engine by using it at its highest level during your dyno test. Most of your testing should be completed at just below the torque peak as long as you are getting the best spark and base jetting. Let the operator know which numbers you are looking to compare and after the test he will hand you a printout.
  • Use the collected data channels for analysis to gain the most from the test. Do not pay too much attention to the correction factors because that aspect generally provides an unrealistic level of perfection. However, you should be weary of your power numbers if the correction factor is abnormally large.
  • The test generally takes 6-8 hours in total. Multiple tests are run to validate the numbers by making sure there are very minimal differences at each test point.

General Steps to Expect at a Dyno Test

  • A technician will ask you if there are any areas of concern such as poor gas mileage, surging, low power, issues starting hot or cold, stuttering or missing, etc.
  • Next, the tech will make sure the engine is sound by checking the engine compression.
  • A visual inspection is conducted to look for evident problems. These can include damaged vacuum tubes, presence of oil, burning or fragile plug wires, a carburetor that is contaminated, etc.
  • In the next step, the tech will establish the proper spark plug heat range to use depending on your particular application. For example, a vehicle that will be hauling a heavy load will need a colder spark than that of the same truck that is used only to commute and will not see a heavy load.
  • The distributor will then be removed and put into a synchrograph. The synchrograph will dynamically and meticulously test the distributor to ensure it is sound mechanically.
  • The tech will likely then modify the centrifugal advance range. This will give you an increase in the responsiveness of your engine and increase power. They will also adjust the vacuum advance to give you better fuel economy.
  • Ignition components will be inspected and replaced if they need to be.
  • Finally, your vehicle’s drive wheels will be placed on rollers in order to run the dyno test. It is tested with your engine running and in gear during various speeds and load conditions. They will look for the engine’s level of performance by comparing the horsepower that is being sent to the drive wheels and the amount of vacuum.
  • More than likely each circuit on your carburetor will also be assessed with an air fuel ratio monitor. These can be adjusted to provide the greatest driveability and efficiency.

PROs and CONs of a Dyno Test

PROs

  • Can give you a comprehensive way to visually see the levels of your engine performance.
  • Gives you a way to tweak engine and components to increase performance, torque, and gas mileage.
  • Certifies your work.
  • Checks for issues not obvious to a visual inspection.

CONs

  • Dyno tests that are not properly calibrated or maintained provide inaccurate results.
  • Inexperienced technicians running the test also provide inaccurate results.
  • Valid conclusions must include simple factors such as air and oil temps that are often overlooked by inexperienced test techs. For example, a temperature increase of 45 degrees can show you an inaccurate reading that claims you have a 1 ½% increase in power.

dyno test

Conclusion

A dyno test can give you an inside look into your engine’s performance. The graph makes it easy to visually compare your output levels. It will allow you to adjust settings that can increase your torque, horsepower, and fuel economy. An accurate dyno test can provide invaluable information to really get your vehicle to its peak level of performance. Be sure to find a reputable testing site that will give you accurate results. This is because they take pride in their facility and upkeep of their dyno testing equipment. If you need advise from the tuningguru just contact us!