While some people like to use a dynamometer to measure rear wheel horsepower (RWHP) for bragging rights, we’ve learned before from Dynojet Research that a dyno can be used for far more than just horsepower and torque.
Tuning a vehicle on a dynamometer is the best way to make sure that you’re getting the best performance by obtaining readings from the ignition and exhaust. These readings can help you tune the vehicle by using the dyno to assimilate certain conditions, such as load, or help to diagnose problems, like high speed misses.
Once the vehicle is strapped down securely and a test run is made, you’re almost ready. However, there are more steps that are required to get the data you need. First, in order to properly tune the vehicle, there are two important connections that need to be made to obtain the engine (rpm) and acquire the vehicle’s air/fuel ratio (A/FR).
The first thing that we need to help with the results we get from a run is the engine speed, or RPM. As we see in the video above, there are a few ways that this connection can be made, and the most common method is inductive pickup. Getting a clean and accurate signal is one of the most important parts of getting a good engine speed and torque reading.
For some vehicles, it may be difficult to find a good signal, and Dynojet provides other methods, including tach output wires, fuel injector signal wire, or any rpm dependent trigger output.
The air/fuel ratio (A/FR) is what helps the dynamometer’s software to determine whether an engine is running too rich or too lean, throughout the the entire rpm range of the vehicle. This helps to tune a vehicle – especially a carburetor – and provides information that might lead you to use bigger or smaller fuel injectors.
In the video below, you can there are several methods of measuring the A/FR, and you can program you Dynojet Research dynamometer to get more accurate readings, and sensors are simply plugged into the Dynoware RT module. In olden days, we simply had a probe that was inserted into the tailpipe, but today there are wideband O2 sensors that can provide the information further up the exhaust system closer to the header, and other ways to acquire information from the exhaust.