The Floating Widget

LFS GRC2

LFS Gear Ratio Calculator: Development Log

7th May 2006 - v2.5.3 (1211KB/1975KB)
(v2.5.3p adds a Polish translation)

Car specs updated to reflect changes in LFS Patch S
Tyre grip values updated to reflect changed in LFS Patch S
BMW Sauber car added
Open top UF1000 removed - specs had been made identical to UF1000 (closed), so was redundant
Accuracy of aero affect on car balance now improved greatly
Tried to flatten the torque curves further for the BMW Sauber but my algorithm still can't reproduce the torque curve for this car :-[
Car list re-ordered
More international support: user can now press "," (as well ".") for use as a decimal point without it being ignored
Web address updated to point at my new URL

9th December 2005 - v2.5.2 (1204KB/1971KB)

GRC is now translatable, ships with translations in Czech, Dutch, German and Finnish
Acceleration times are now caclulated to 1/20th of a second
Revised clutch simulation (slightly less simplistic)
Altered undertray effect location (hopefully more accurate)
The UF1000 is now available in open roof guise
Cars now have independent idle speeds
New GRC-style car skins for the road cars (by yours truly... apologies for my lack of creativity)
Some minor bug fixes and improvements

1st October 2005 - v2.5.1 (1050KB/1577KB)

Added weight transfer caused by acceleration (but all cars used shared CoG height atm)
Updated the logo, thanks to MadmanCZ for creating the gear knob
5 minor bug fixes (for things that I broke with the last update)

11th September 2005 - v2½ (1042KB/1572KB)

Added acceleration calculations (0-60 times, quarter mile ETs, etc)
Added two more graphs: tractive effort and speed vs. time
Added tyre choice selector (slicks, road, knobblies, etc)
Added ability to blow the tyres (fun - just missing mulitmedia sound affects :p)
Made tyre contact patch shape diagram zoomable and added grid
Added options to configure the new features; options.ini spec has had to change
Seperated the graph options from the misc options tab; replaced the text boxes with sliders
Made the torque curves flatter at high engine rpm
Internal: made better use of arrays, which shortened code and reduced the filesize
Still ended up with a larger to-do list than when I started...

24th August 2005 - v2.2.1 (930KB/1417KB)

Fixed tyre frequency formula, it is no longer affected by downforce
Moved the about box into the info panel

12th August 2005 - v2.2.0 (932KB/1425KB)

Added lift distributions into aero tab
Added the load from downforce onto the tyre for deformation purposes
Updated tyre deformation formula - it's basic but doesn't have the flaws of the old "balloon" style physics
Some slight interface changes
Internal: tidied up some code, particularly sub calling on program load
Fixed a bug where the speed obtainable in reverse wasn't displayed correctly when in Speeds ==> Ratios mode

6th August 2005 - v2.1.1 (918KB/1400KB)

Slight re-design of the aerodynamics tab
Numerous (very) small improvements
Fixed tyre stiffness bug (it was out by a factor of 100 - whoops!)

3rd August 2005 - v2.1.0 (917KB/1396KB)
Added full aerodynamics modelling (undertray, adjustable wings, etc).
Had to give aerodynamics its own tab otherwise I wouldn't have been able to fit it all in.

28th July 2005 - v2.0.7 (888KB/1342KB)

Tweaked aero properties a little more.
A couple of changes and additions to the info tab.

20th July 2005 - v2.0.6

Fixed opening files outside of program folder from causing errors.
Drivetrain efficiency now viewable in the Info tab.
Custom car preset editor now fills in all default values when car is selected, all 18 cars are now in the list.

19th July 2005 - v2.0.5
(v2.0.5b fixes two additional small bugs)

Fixed editing of custom car presets (it now works).
Added tyre stiffness and tyre frequency information.
Added units of stiffness into the options.
Updated car aerodynamic properties.
Altered the rev limiter and a couple of other odd changes.

12th July 2005 - v2.0.1

Added a quick hack to support users who use a comma for their decimal sepatator.
Options now auto-load on program startup.
Fixed a file loading bug.
A couple of miscellaneous things.
Improved the manual.

7th July 2005 - first "official" release of v2.0!!!

Obtained S2 car specs.
Fixed a unit conversion bug.
Added missing car pictures.
Wrote the manual.

8th June 2005 - beta #6
No more major changes planned before "official" release.

Added torque curve estimation and graphs.
Added top speed estimation.
Substantial code optimisations that decreased filesize by 80KB (although extra features put 32KB back on again).
Various small bug fixes.
Improved layout on the Info tab.

20th March 2005 - beta #5b
Just a couple of minor changes from beta #5.

Added unit converter for use with the custom presets editor.
Fixed a little options panel bug I noticed.
Updated car pictures - also decreased jpg filesizes a little.
Tweaked axis lines on graphs.

12th March 2005 - beta #5
Beta #5 continues to make use of the extra information added with beta #4.

Added tyre slip, speeds should be more accurate now.
Added pictures of the cars.
Played around with the layout.
Fixed the odd little bug or two I came across and prevented the crash when trying to load the options.ini and it doesn't exist.
Added readme.txt.

5th March 2005 - beta #4
With still no sign of LFS S2, I decided to add some features now that I was planning to add after the beta development stage. This meant a lot of internal changes. Not all the features have been added yet as they involve a lot of work. I also dropped the "public" in the name as that's fairly obvious now.

Replaced "View Car Info" table with full Info tab, more detail available.
More information per car stored (27 details vs 14 previously), so lots more information viewable
Custom presets format changed to cope with new information - old presets will not load so will have to be recreated.
Both front & rear tyres can be individually analysed on all cars.
GRC now supports just about any units you care to think of, all configurable from the options panel. Make sure you replace your options.ini if you have a previous version.
Also a slight change to the .grc format means they won't load either, so basically delete everything and start from scratch with beta #4. The improved functionality is worth the changes, however the .grc and .cup file formats should never need to change again.
Layout still needs more work.
More features planned to be added before final release.
Also need S2 car specs before final release.
Also fixes issues a few bugs I found lying around.

27th February 2005 - public beta #3b
Fixes issues and bugs introduced with beta #3.

26th February 2005 - public beta #3
Some interface improvements. Added slider input for gearing and the two gearing tables are now linked.

13th February 2005 - public beta #2
Fixed issues that were discovered from public beta testing. Nothing exciting, just some bug fixes. Webpage updated and GRC history added (what you're reading). LFS GRC approaches it's first birthday (wooooh).

10th January 2005 - public beta of GRC v2.0.
Fixed issues that arose from initial beta testing. Webpage created for GRC.

28th May 2004 - LFS GRC v1.90 (51KB/151KB)

Improved the accuracy of the suggested rpm values - they are now within 100rpm of when the red light comes on in LFS (which is good enough for me).
Added the ability to name the presets (for LFS Tweak) I introduced with v1.85.
After downloading LFSTweakPro, I realised you can tweak the S1 cars, so removed the restiction to only create presets based on the demo cars.
Added comments everywhere to try to aid ease of use (explanations, etc).
All engine revs are rounded to the nearest 50rpm, to try and make it a little clearer.
A couple of other miscellaneous things.

20th May 2004 - LFS GRC v1.85 (44KB/131KB)
Added an extra tab where car information can be entered to get GRC to work with cars other than what are present in LFS by default. This is so the gearing could be calculated for cars created with LFS Tweak.

18th May 2004 - LFS GRC v1.8 (22KB/94KB)

Added a tyre pressure slider and removed the old estimated deformed values. The tyre pressure slider is nowhere near 100% accurate but should be better than fixed deformation values. Tyre wall stiffness is not taken into account, so the calculated deformation is (far) too great at very low tyres pressures. This shouldn't be a problem though as you shouldn't be using pressures that low anyway.
Improved the estimation of the optimum shift point (it now takes the number of gears into account), and works well enough with standard gearing patterns.
Seperate final drives are available for each of the tables.
I've fixed the left-hand graph - it works properly now.
Both graphs have minor other improvements.
A few miscellaneous visual improvements.

27th April 2004 - LFS GRC v1.7 (18KB/78KB)

Car selectable from a dropdown list and all car data is filled in automatically.
All car data now stored in the data tab.
Usage instructions have been added, explaining some of the new terms used.
User changeable values are colour coded to make it easier to understand if you are not familiar with the spreadsheet.
Added engine speed after the change.
Added a very basic estimation of the optimum shift point (though the user-entered values are still used for the calculations).
The engine speed can now be individually specified for each gear.
Speed/rpm plots have been added to help visualise changes.

4th March 2004 - LFS GRC v1.6 (6KB/30KB)

Added the actual unloaded wheel diameters (instead of estimates) into a new data tab, courtesy of red.eye.
Re-estimated the tyre deformation to give diameters more accurate to the in-game values.
Renamed the km/h tab to the metric tab, as I used metric measurements for the wheel diameters as well.

16th February 2004 - LFS GRC v1.5
Added another table where you can enter speeds (instead of ratios) and have the necessary gear ratios calculated.

15th February 2004 - LFS GRC v1.1
Added a second worksheet that outputs the speed in km/h for those not so familiar with mph.

14th February 2004 - LFS GRC v1.0
First release, is a Microsoft Excel spreadsheet. Features:

User enters a final drive ratio, an engine speed, a car speed, a tyre diameter and a set of gear ratios.
The spreadsheet will then calculate the car speed at the given engine speed for each of the gears.
It will also calculate the engine speed at the given car speed for each of the gears.
A data table is included that lists the tyre diameter and reverse ratio for all of the cars in LFS.