Car-Calculator

a spreadsheet (.ods) file to generate graphs for your car

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Current features:

1- outputs RPM Vs Speed graph (similar to racing games)

2- outputs Torque Vs RPM per shift

3- Torque & Horse Power Vs RPM (usual graph)

4- displays Final Gear ratio (Transmission + differential)

5- accepts either measured date or from datasheet

output example

How to use:

1- download latest release from releases page

2- open it using spreadsheet app (tested with liberOffice and is the recomended)

(it is recommended to create a copy and using the copy)

3- go to "interface sheet"

(note that i use dark theme, UI may vary)

you should see the following :

start by changing number of shifts [current limitation is 10 gears]

then redline limit (the fastest your engine can run)

[current limitation is 9000 RPM] and is counted from 500 RPM with increment of 500 RPM

Gear ratio:

if you have Transmission and differential gear ratio then check the box(these are usually found in the data sheet of the transmission):

    if you have final gear ration (both combined) then set differential gear ratio to 1 and fill the rest in the table bellow

then insert gear ratio per gear(shift)

if you dont have, dont worry and uncheck it

then insert speed and RPM (how do i get them?)

to get speed and RPM you need OBD2 adapter and an app like torque , then set it up to show RPM and Speed

after that you need to go through each shift and take a screen-shot for every shift near the specified RPM per transmission:

for MT (you dont need any clutch slippage) RPM of 1200 is good enough

for AMT and DCT it is better to keep RPM at 1700

for AT with torque converter RPM > 2000

Note1: for AMT,DCT,AT use manual mode or shift limiters

Note2: for AT be sure that torque converter is locked and is not slipping.

Note3: when taking a screen shot, its better to be driving at constent speed

Note4: adhere to traffic laws and insure your and surrounding safety.

then insert speed and RPM:

if you have "engine" torque and horse power then check th corresponding box:

then fill the corresponding table

dont fill columns with RPM 0

lastly insert your tyre size

to see the results go to output sheet

you will see the graphs like this:

this is because there is extra data

right click on the graph, then click edit. after that go to data range from right click menu and remove extra data in data series tab:

edit graphs and add notes as needed

change colors and so on

lastly print

on "output" sheet, press 'Ctrl + p' to print the sheet

and enjoy

you have an idea?

For any suggestions, feel free to open discussion

To Do:

• add development documentations
• make it a web app