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Project Cars 2 Gear Ratio Calculator V0.5

I was inspired by Jussi Karjalainen's amazing suspension calculator to start work on a tool to make work of tuning gear ratios more efficient. The pale yellow cells are editable by the user. Calculations are done in green cells.

To use the calculator:

Input available gear ratios and final drive ratios for the specific car (A2-A37, C2-C25). Available ratios can be found by scrolling through the ratios in the "ECU/Engine/Gearing" tab in the car setup menu. This populates drop-down lists that will make the rest of the steps much faster!

Use the drop-down lists to select current final drive ratio and gear ratio (G1-G9).

Calculate the wheel size for your car: Choose the highest gear you can hit redline in (D28) (Usually 2nd highest gear). Select the current final drive ratio and the gear ratio for that gear (D26-D27), and record the speed at redline (D29).

Input the RPM at the shift point (D32). Note: the optimum shift point may not be at the engine's max RPM (redline RPM), depending on the engine's power characteristics. If you don't know the optimal shift point, you can use the RPM at redline.

Optional: If different from the shift point RPM, users can input redline RPM, max power RPM, and power-band start RPM to draw pretty lines on the graph (D33-D35). These lines only serve cosmetic purpose on the graph, but can be useful for reference when choosing gear ratios. The powerband start RPM defaults to a formula that approximates where the engine might start to enter the powerband, but only works if the RPM at shift point is different from the RPM at redline. Minimum race speed and maximum race speed also draw lines on the graph, and are optional as well (D36-D37). Min and max speeds can by found by simply racing the track and noting the min and max speedometer readings.

Change highest gear ratio to achieve desired max speed. In the example, the highest gear is 6th. The theoretical max speed of the gearbox at the shift point and at redline are shown in cells Q4 and Q7. If it's over the set desired max speed, the cell turns green. The idea is usually to just hit the shift point or redline in last gear, with a little room for extra speed while drafting. In my example, I exceed the RPM I would normally shift at, but do not hit the engine limiter in last gear.

With first gear, there are two ways you would generally go about choosing a ratio: If the race is a standing start, set the ratio as high as possible to launch without much wheelspin. If the race is not a standing start, it can be set so at the minimum race speed, the RPM is at the powerband start. Depending on the minimum race speed, this way may make it difficult to start from a dead stop (i.e. after a crash or pitstop). In my example, I have chosen a ratio that is a compromise between starting from a dead stop and accelerating out of the slowest corner.

Continue to adjust the remaining ratios between 1st and last, keeping in mind the speed range (N2-N9) and minimum RPM (O2-O9) for each gear. You want the speed range for each gear to be close to the same, except for 1st gear. In general, you don't want the lower gears' minimum RPM to be above the powerband start, as this might forces you to shift very quickly. In my example, the speed ranges are fairly consistent, getting slightly smaller in the higher gears, which is ok. Usually it's not possible to get them perfect, because you only have so many ratios to choose from, but close enough will work.

To-do list:

- Create a dropdown menu of all cars with changeable gearboxes, so manual entry of available gear ratios, wheel size, redline, and max power is not needed.
- Create another tool for tire pressure/temperature and camber calculations. (In progress)

Let me know what you think! I'd love any feedback or ideas for new features!