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Old 30th July 2011, 19:08   #1
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Default Torque-Power Curve Generator

Hello everyone,
As the title suggests, I've been working on a torque-power curve generator.

Now, this generator is a Google Docs spreadsheet. The idea is that you enter some basic informantion about a car (or two, more on that in a bit) of your choice and the spreadsheet will output the following graphs.

1. Graph showing Torque and power plotted against RPM
2. Graph showing RPM in each gear (separately) plotted against speed
3. Graph showing Torque going to wheels/Ton in each gear (separately and, hopefully, corrected for transmission, wind and losses) plotted against speed.

Now I'm designing this in such a way that you can display information related to two cars at the same time. It would serve as a good comparison tool for acceleration, gearshifts etc. - especially the third graph.

I've organized the whole spreadsheets into the following
1. Introduction - Just some general stuff.
2. Input sheet - Enter in all the data about different vehicles here. Fields that can recieve data are marked in bold
3. Power-Torque-RPM Sheet - The data behind the first graph. RPM interval can be varied according to your preference and requirement.
4. Power-Torque-RPM Graph - 1st graph
*5. RPM-Speed Sheet
*6. RPM-Speed Graph
*7. Torque/Ton in gear sheet
*8. Torque/ton in gear graph

The ones marked in star aren't done yet. This project is only like 1/3 done.

Anyway, without further ado, here's a link to the spreadsheet


It's a read-only link, so go to the file menu and either download or save a copy.

A few limitations
The most important is that this is a purely theoretical excercise. Further, data commonly provided by manufacturers is usually insufficient for any reasonable level of accuracy. So, use it at your own risk. It should be okay for general comparisons though
No way to calculate turbo lag

Known problems with this version
1. A minor problem with maximum rpm at which peak power is produced. If it's the same as minimum rpm at which peak power is produced, it doesn't get displayed
Temporary workaround - Put Max power rpm atleast one above the regular one as in the example
2. A flaw in the way top end power is calculated. Should keep power constant but it doesn't. Shouldn't be hard to fix.

Things to do (in order)
1. Fix known issues
2. Add two more optional reference points for torque curve calculation
3. Do graph 2
4. Fix problems with graph 2
5. Do graph 3
6. Fix problems with graph 3

So, what do you people think? Any ideas, suggestions, bugs, musings, ramblings cursings will all be welcome, as long as they are all within rules, ofcourse

PS. I'll post a link to my earlier attempt at anything like this. This one relates only to a Tata Indica Vista 1.4 TDi. It's difficult to modify it for user input - So, I started from scratch, with a new framework altogether. Still, it's useful to get an idea of what I'm trying to do


Oh, on a related note, I think that 0-100 times, especially by themselves, are of very little value even for outright acceleration. once this is done, I could probably clearly demonstrate that gearing plays a major part! What we need are speed/time graphs....but oh, well, that's for another topic

Last edited by nukeblitz : 30th July 2011 at 19:14. Reason: Little errors...
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