Summary of update 1.0b
Installation instructions are in zip file.
Main differences in this update
-center of gravity height increased (more pronounced weight transfer, longer more accurate braking distance).
-increased longitudinal slip (less wheel spin longitudinally under throttle, lateral is the same as before and based on real telemetry for gravel and tarmac)
-cars are more neutral interaction, less understeer, more oversteer on braking on gravel.
-increased peak grip for gravel, but lowered rolling resistance so cars are easier to rotate at lower speeds, (they don’t bog down or understeer as much at lower speeds) with just a flick of the wheel or tap on the brake can send the car in a controlled slide that is easier to recover from.
-aerodynamics, returned side force values to original spec, this was experimental and it was too strong of a setting. It made cars less responsive to steering inputs and added understeer. Downforce is still present and higher at faster speeds so you are rewarded for pushing the car at higher speeds.
-mid engine 037 and Stratos have higher friction lower slip angles for the rear fatter tires, easier to control less oversteer on corner entry but still a handful.
Issues -Alpine and Renault 5 turbo rear tyre grip do not respond to modding. Also, their initial vanilla physics are different than any of the other cars so I have given up on them as far as tyres go. The other values (weight, inertia, etc are still modded)
-fixed correct rev limits for a lot of cars, including modern WRC cars rev up to a correct 8500 rpm now.
*For the center of gravity height I used real data as much as I could find. For example WRC Focus 07 raised cg height from 34 cm to a more accurate 40. This makes a big difference in the way the cars drive.
Info about Dirt Rally loose surface model
Learned more about how the handling model works by looking at an early 0.3 version of the game which included a surface_materials.mxl in the main directory. This file is hidden in the latest version. It includes all the surfaces with different depth and soil densities for loose surfaces. The CTF custom files that I’ve been editing are just the reference tyres values that interact with the surface values from the surface_materials file which has over 21 different surfaces. (including different values for the compact soil where tyre tracks are located)
The surface file is hidden in the latest 1.23 version of the game so I cannot edit all the different surfaces so any changes that I’ve made are still tyre reference values that interact with the values of all surfaces.
This is why setting a reference slip angle for the same tyre will still yield different results since the actual slip angle depends on the tyre value interacting with soil density, soil depth, car properties, suspension setup, weight dist. Cg height etc) and this is how it should be.
There is a hard gravel tyre used in Greece and dry Finland and a soft gravel tyre which is used in all of wales (cold and damp weather) and rain Finland. Same for tarmac dry tarmac compound and wet tarmac compound, snow and ice so six tyres for all the courses used.
(I want to thank Come Over Gaming for the RFPE plugin and the ability to mod the physics
also lots of thanks to Avo77 and Forzakof for helping me with the ctf values)
-Increased central downforce (except for Pikes Peak, these have strong aero effects already and just modified to correct drag coefficients)
cars with aero kits are more noticeable, more grip at higher speeds, cars don't fly as high on jumps.
-changed drag coefficient and frontal area to realistic values
-fixed vagueness in steering for RWD cars
-tweaked tarmac to higher grip
-added separate CTF files for gravel/loose surfaces and tarmac, this affects suspension height and settings which cannot be changed when using RFPE plugin.
Fixed grip from copying error for all RWD and FWD cars for gravel, wet gravel and snow. Sorry about that. Too many cars.
-Incremental increases to yaw and pitch inertia, more pronounced weight transfer, reworked values to compensate for driver and copilot weight. Used real vehicles for reference as much as I could find, as well as an inertia calculator for rfactor2.
Increasing the yaw inertia proportional to driver and copilot,
added weight makes cars behave better over jumps, cars were already more planted before but this update makes Finland a lot more drivable. Also, with the increased inertia it is harder to recover a landing from a really high jump.
This is a comparison between WRC STI 0.7 version on top and 0.8 on bottom
I recommend using the brakes mid air to adjust the pitch forward and gas to make the car lean backward while midair.
Also cars suspension soaks up bumps better so RWD cars are not as twitchy in the rear when cornering. Cars carry more speed through corners so brake a little earlier.
-Adjusted default braking bias on RWD cars to be more neutral, easier to trail brake,
brake bias adjustment doesn't seem to work in game with the plugin but all other car settings work normal.
-Audi Quattro power delivery smoother, earlier version was not very responsive at low rpm.
This update includes the RFPE launcher and plugin.dll
extract Alt Physics 0.8 files in Dirt Rally main folder
Start RFPELauncher then START Dirt Rally
(I thank Come Over Gaming for the RFPE plugin and the ability to mod the physics)
Changes in 0.7
(Working on downforce/aero next update)
Increased brake torque values, brakes properly lock up on gravel.
Tweaked Greece dry gravel, sliding friction doesn't drop off as much as Wales, (was able to get more information on dry gravel)
Tweaked rear slip angles on gravel tires, there is more of an initial lag/understeer when tires first start to dig in heavy gravel.
Car still oversteers under high throttle, heavy braking and high body angles.
Incremental changes and fixes in this version
Increased grip for Group B and Group A to more closely match WRC cars, gravel grip was lower on these cars and it was really difficult to keep on track in rain gravel compared to other awd cars. Still not as grippy as 2000s and modern WRC cars but more manageable.
Increased slip ratio for gravel to match deep gravel.
Longitudinal slip comes at a higher wheel spin, feels more natural, engine bogs down before reaching redline doesn't spin as freely like it is on ice. Change is not drastic from 0.5. Wet gravel will still spin more freely.
Lateral grip remains the same as 0.5 version.
-Audi Quattro Sport RPM revs up to 8000, HP peaks at 7500
changed weight to correct fully loaded weight, as well as weight balance.
-Fixed power of Ford Cosworth, doesn't feel as sluggish.
UPDATE -0.5 (updated renault file in second folder after extraction of zip)
-Increased mass to account for drivers, co-pilot and fuel.
-Used Dash Meter Pro to adjust grip level to match real telemetry for tarmac and gravel.
-Braking should be done earlier, car weight transfer is more pronounced. Trail braking and oversteer under braking more pronounced. Brakes lock up easier in corners.
-Fixed understeer under braking in Ford Escort MKII and other RWD cars.
-Increased rpm limit on Audi Quattro Sport to 7,500 rpm
-Fixed weight distribution of Lancia S4 from 55% front to a correct 45% front
Dirt Rally Telemetry using Dash Pro Meter
If you want old damage and new physics, restore your raceload.jpk file and n2d files from the RFPE backup folder.
Tarmac in action
ps (friction values for ice/snow not comparable to other surfaces, ice values is higher than gravel but still feels lower in game because of other factors controlled by the game for that surface, including but not limited to rolling resistance. )
In Codemasters defense, their grip values for tarmac in modern Rallycross are already lower than Germany and the loss of grip is 20%(more realistic) than the 12% loss on germany tarmac.
Original Alpine A110 also has very different grip values than the rest, probably since it's the lightest of all the cars, much lower grip values for all surfaces.
0.2 Version with all cars
Added Pikes Peak, 2000s, Rallycross, 1960s, 1970's.
Improved inertia values for most cars and other small tweaks.
Cars are more planted at higher speeds and bumps, subtle change from 0.1.
Found grip values for Wet Gravel, reduced accordingly for Finland Pikes Peak and Wales. Much more fun in the rain!
Input is appreciated!!!
1. Have RFPE 0.4 installed, (available on this site)
2. Extract all CTF files in main Dirt Rally folder then start RFPE mod 0.4 and play.
I'd like to thank the creators of the RFPE mod and Forzakof for all the hard work. Also thanks to Avo77 for pointing out how to mod the rest of the cars. Would love some input from experienced sim racers and real drivers.