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Dyno software for inertia dynos in the race shop or at home
The OnTrack dyno software can be used for any type of inertia dyno where the engine accelerates a mass such as a flywheel or heavy rollers. Many customers use OnTrack for their "home built" inertia dyno projects where they build a dyno frame with a motor driven flywheel or wheel driven rollers and use the software with a Speed Sensor triggered by a magnet on the flywheel/rollers. The speed sensor plugs directly into a PC or laptop sound card port with no other hardware required. This setup provides great dyno results at an affordable price.
Dyno software for vehicle acceleration dyno runs at the track
Vehicle acceleration type dyno runs use the same principle as a fixed inertia dyno. Instead of accelerating a heavy inertia flywheel or rollers, the engine is dyno tested by accelerating the total weight of the vehicle. To measure the vehicle acceleration OnTrack can use data signals from either the vehicle speed or engine rpm. For example you can use an Ignition Sensor that clips onto a spark plug lead to pickup engine rpm, or use a Speed Sensor triggered by a magnet to pickup vehicle speed, or use any of the speed or rpm signals from the vehicles electronics.
An acceleration dyno run is made using a laptop computer or data recorder as follows:
- Plug a signal lead into your laptop or data recorder
- Start the OnTrack software
- Enter the Total Vehicle Weight, including driver/rider
- Enter the weather conditions (Temp/Humidity/Barometric Pressure)
- Start the engine and select second gear on a straight section of track
- Accelerate the vehicle from low rpm through to red-line
- OnTrack will calculate and graph HP and Torque for the run
- The dyno results and data are stored in the OnTrack database
- You can graph and compare up to 6 runs on the same dyno chart
Data sensors and data signals
The OnTrack dyno software can use any signal from a sensor or data source that has a frequency related to the speed of the flywheel/vehicle or engine rpm. Examples of these are:
- Speed Sensor triggered by a magnet on the dyno shaft (recommended for inertia dynos, see the Dyno Speed Sensor page for Speed Sensor build instructions)
- Inductive Ignition Sensor (clips onto a spark plug or ignition lead)
- Engine rpm signal from the ignition system or ECU
- Vehicle Speed signal from the vehicle speed sensor or ECU
- Signal to a vehicle's digital tacho or digital speedo
- DIY sensor using a trigger or optical "chopper"
Note: Only one of these signals, speed or rpm, is required. The other is calculated by the software. For example, if you use a speed signal then the engine rpm is calculated using the transmission ratio.
The OnTrack software can use the signals from any of these sources, along with info in the OnTrack database, to calculate the vehicle or flywheel acceleration and the engine rpm through the rev range. Given the total weight of the vehicle or Moment Of Inertia of the flywheel, and the weather conditions at the time of the dyno run, then OnTrack calculates and graphs very accurate dyno charts.
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