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klw7890
07-03-2018, 20:38
Download here:

Project Cars 2 Gear Ratio Calculator V0.5 (https://drive.google.com/open?id=1F4TVmLmvhRD4PoVgJ_3UfzdPYBwTBrOh)

I was inspired by Jussi Karjalainen's amazing suspension calculator (http://forum.projectcarsgame.com/showthread.php?54023-Project-CARS-2-Suspension-Calculator-v0-96) 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!

g.stew
07-03-2018, 21:39
Thanks! I look forward to trying this out tonight.

Jussi Karjalainen
07-03-2018, 22:31
Good man! Lovely to see people work on this kind of stuff. I had planned on doing it myself but now I won't have to. =)

Could a mod sticky this?

eracerhead
07-03-2018, 22:48
I'd made a much more limited version of my own for one set of gear ratios, so I'll definitely keep this one bookmarked. Nice work.

GTsimms
08-03-2018, 01:21
Good man! Lovely to see people work on this kind of stuff. I had planned on doing it myself but now I won't have to. =)

Could a mod sticky this?

Done!

g.stew
08-03-2018, 22:42
I tried it out last night and it was very useful. I was able to get my exact Shift RPM, Speed @ Shift in 1st, and Min/Max Race Speed from my saved telemetry data in vrHive, so it was easy to get started.

The only problem I ran into was with Excel 2013. The Max Speed(L4) and the lines on the graph for Powerband Start RPM, Max Power RPM and Redline RPM don't work. As soon as I change anything in D1-D9 they disappear. The Max Speed formula (the part I can see) is using MAXIFS, which is only available in Excel 2016. I'm not sure if it's the same problem with the graph lines, or if they depend on the value of L4.

It still works great without those, but I'm not sure if there is an alternative way to calculate those without MAXIFS.

Anyway, thanks again for this addition to the growing library of setup tools.

klw7890
09-03-2018, 05:35
I tried it out last night and it was very useful. I was able to get my exact Shift RPM, Speed @ Shift in 1st, and Min/Max Race Speed from my saved telemetry data in vrHive, so it was easy to get started.

The only problem I ran into was with Excel 2013. The Max Speed(L4) and the lines on the graph for Powerband Start RPM, Max Power RPM and Redline RPM don't work. As soon as I change anything in D1-D9 they disappear. The Max Speed formula (the part I can see) is using MAXIFS, which is only available in Excel 2016. I'm not sure if it's the same problem with the graph lines, or if they depend on the value of L4.

It still works great without those, but I'm not sure if there is an alternative way to calculate those without MAXIFS.

Anyway, thanks again for this addition to the growing library of setup tools.

Thanks for letting me know! I'm uploading V0.2 soon. I've removed the MAXIFS (not sure why they were there in the first place :confused:). As for the other problem, I have the new excel, so I'm not really sure why it wouldn't work. Maybe someone else has some insight. Hopefully the new version will fix your issue!

g.stew
09-03-2018, 21:57
The problems I had with excel 2013 are fixed now. All of the fields and graph lines are working correctly.

The new wheel size calculation part is great too.

klw7890
09-03-2018, 23:11
The problems I had with excel 2013 are fixed now. All of the fields and graph lines are working correctly.

The new wheel size calculation part is great too.

That's awesome, I'm glad to hear it! Enjoy and spread the word :)

OZSIM Endurance
11-03-2018, 13:54
Awesome! I look forward to trying this out

klw7890
19-03-2018, 12:27
New version up! :)

RockWall
19-03-2018, 20:50
Nice one! I seem to have more gear ratios than I can put in the drop-down (using the A45 AMG). Any way to expand the field of the dropdown?

g.stew
19-03-2018, 21:37
Nice one! I seem to have more gear ratios than I can put in the drop-down (using the A45 AMG). Any way to expand the field of the dropdown?

On the previous version, I was able to add rows by right clicking on the last yellow field and selecting insert and shift cells down.

The new version doesn't allow this though because the worksheet is protected.

I needed this on the Porsche 911 RSR which had 41 available gear ratios.

@klw7890 - Can you add more rows for the available gear ratios? I'm not sure what the max number is, but 41 for the rsr is the most I've needed so far.

klw7890
19-03-2018, 22:06
On the previous version, I was able to add rows by right clicking on the last yellow field and selecting insert and shift cells down.

The new version doesn't allow this though because the worksheet is protected.

I needed this on the Porsche 911 RSR which had 41 available gear ratios.

@klw7890 - Can you add more rows for the available gear ratios? I'm not sure what the max number is, but 41 for the rsr is the most I've needed so far.

Absolutely! More fields incoming!....

klw7890
19-03-2018, 22:19
More fields added :)

Zeratall
20-03-2018, 05:21
Great work KLW, as an (aerospace engineer) this approach is taking a linear approximation of the drag bucket (very non-linear). It seems to work okay because you are taking the wheel calculation at a high top speed (worst case scenario). Again great work, but I think its important we take in account assumptions when using tools like this.

Slawek_9
24-03-2018, 16:09
Excellent tools ;)

klw7890
03-04-2018, 16:17
Great work KLW, as an (aerospace engineer) this approach is taking a linear approximation of the drag bucket (very non-linear). It seems to work okay because you are taking the wheel calculation at a high top speed (worst case scenario). Again great work, but I think its important we take in account assumptions when using tools like this.

I see what you're saying, but this tool doesn't attempt to calculate actual top speed. It calculates "theoretical top speed" assuming infinite power to reach redline in last gear. In actuality you probably want to reach "max power" in last gear to get a true top speed for that car, but you usually won't be able to get there on most tracks, except maybe Daytona or Nuerburgring.

The tool purely relates engine RPM to wheel RPM, and converts 1 wheel revolution to a given distance, which yields a travel speed with wheel RPM. No aerodynamics should be at play.

Zeratall
03-04-2018, 16:49
Klw, I completely agree and that's why I said it was a great tool. I think you stated the assumptions perfectly just now, infinite power, zero drag, no tire slip. I was just trying to say it's important to announce assumptions to users. Not all users know the math, some might be confused why they can't even hit there top gear even though they have 6 gears and tools says they can hit 300 mph hahah, I love this tool and thought you did a great job, excited to see what else you have up your sleeve.

slmansfield
04-11-2018, 21:20
Love the tool, but it seems to not work for gears 7 and 8. If I add a ratio, it gives insanely high speeds.

My guess is a calculation is off, but haven't spent any time yet to determine how the calculation is off.