Drive Ratio Calculator

ProScan provides a drive ratio calculator for estimating a vehicle's drive ratio (kph/rpm) for a specific gear. A drive ratio allows ProScan to determine vehicle speed from engine speed for a specific gear. Using a drive ratio allows ProScan's Dyno tool to collect twice as many data points.

The preferred method of determining a drive ratio is by calculating it from known vehicle specifications.

Information Required for Manual Calculation:

• Tire Size [ Tire Width (mm) / Aspect Ratio / Rim Diameter (in) ]
• Transmission Gear Ratio
• Axle Ratio

Estimating using the Drive Ratio Calculator

1. Establish a connection with a vehicle.
2. Open the Drive Ratio Calculator under the Tools menu.
3. Begin driving and put the transmission in the desired gear.
4. Click the Start button to begin calculating the drive ratio. Try to run the vehicle through a wide RPM range while maintaining the same transmission gear.
5. The estimated drive ratio will display when the progress bar reaches 100%.
6. For best results, repeat this process a couple of times and average the results.

Saving the Drive Ratio

Once you have determined the drive ratio for the gear you will use to perform dyno pulls, you should save the number under the vehicle's profile.