Cars (DATA REPLACEMENT) Toyota ZN6 GT86 Improved Physics by Arch

Status
Not open for further replies.

Kyuubeey

@Simberia
Kyuubeey submitted a new resource:

(DATA REPLACEMENT) Toyota ZN6 GT86 Improved Physics by Arch - New generation Toyota FR Sportscar.

13.10.2019 Version 1.0

• Initial release



!!!IMPORTANT!!!

Doesn't require shaders patch!
Recommended download: GT86 Graphics Improvement by Aratbone: https://www.racedepartment.com/downloads/toyota-gt86-graphics-improvement.26498/

!!!IMPORTANT!!!

Includes:
ZN6 GT86 GT
ZN6 GT86 S1

Credits:
Physics and custom UI file by Arch/Kyuubeey
Versions icons by Content Manager
UI file torque curves by x4fab's AC Torque Helper
Everything else by Kunos Simulazioni

Special thanks:...

Read more about this resource...
 
Hi Kyuubeey, can you please explain the changes you've made in detail?

I have owned a 2013 Scion FR-S and currently own a 2018 Subaru BRZ so I'm pretty interested :)

I'm mainly interested in changes to the 2017+ car and specifically the "Performance Pack" so it feels more like what I drive now:

-4.3 final drive (from 4.1)
-Sachs suspension with new spring rates ("10% higher front and 15% lower rear" -- can't seem to find the exact numbers in a quick search, but the zenki BRZ and 86 have different spring rates)
-Sway bar adjustments (F: 18mm R: 15mm; previously F: 18mm R: 14mm)
-Brembo brakes (stock 86 brake pads are truly awful, but the brakes seem fine in AC so maybe this is not worth messing with)
-17x7.5" wheels (from 17x7"). OEM tires are still 215/45/17 (but I have 225/45/17 which fits the 7.5" wheel better, so it would be neat to have that option in game).
-5 more peak HP, more low end torque

yH9HeX3.jpg


There were literally hundreds of changes to the MY17 refresh, but I'm more concerned about the really noticeable ones like the final drive and suspension settings.
 
@hushypushy

Considering I haven't made the 2017 car, I can't comment on that. I don't think I will either, perhaps later when the base is more developed. Car still needs a bit of work and it's outdated atm.

In terms of changes, everything except some misc. stuff like probably the AI file and autoshifter settings and some generics.

If you insist on a list, it's the same as usual:

Car mass, inertia, CoG
Suspension geo from scratch
Dampers, springs, stabilizers
Engine, diff, trans
Aero
Tires
Setup ranges


Biggest change is likely figuring out approx. curves for the multilink rear and converting it into DWB without destroying the other aspects too much.

I think this is the latest curve:

560 = 1.34 , -0.37 / 0.90 , -0.26
540 = 0.66 , -0.13 / 0.51, -0.09
500 = -0.74 , 0.06 / -0.68, 0.05
480 = -1.49 , 0.04 / -1.47 , 0.05

There's always some inaccuracy in droop on these, maybe with some work it could be made closer, but the Supra which was from a laserscan base was similar albeit a bit closer. I don't know if I have the energy to completely rework the rear again just so droop has more gain.

Supra:
Rear ML Orig

163, 385 = 0.60, 0.08
143, 364 = 0.15, 0.04
123, 342 = -0.33, -0.04 Ref
103, 322 = -0.80, -0.14
83, 302 = -1.33, -0.27

Rear DWB Adjusted

163, 385 = 0.51, 0.10
143, 364 = 0.13, 0.05
123, 342 = -0.32, -0.04 Ref
103, 322 = -0.82, -0.15
83, 302 = -1.38, -0.27

Nissan S-rear also is a tad closer in droop than our GT86.

Rear ML Orig S14

222, 314 = 0.37, 0.15
202, 294 = 0.23, 0.09
182, 274 = -0.00, -0.00 Ref
162, 254 = -0.30, -0.14
142, 235 = -0.70, -0.33

Rear DWB Vanilla S14

224, 611 = 0.47, 0.14
184, 571 = 0.00, -0.00 Ref
144, 532 = -0.61, -0.33
 
Thanks!

I'm just curious and I like detailed change logs :cool: In a previous job I used to do laser scanning of cars and tracks, but I've never been involved with the physics side.

I'm wondering about a few things, and hoping you can answer a few questions for me :thumbsup:

When talking about simple values, I'm interested in the comparison. For example, the car's mass was originally set at X but you set it to Y.

When it comes to things that are multifaceted, I'm interested in the explanation. For example, the engine's characteristics were "this" before and you changed them to "that". I just like reading about that sort of thing.

And then I have some deep, philosophical questions. I wish I could pour you a drink at this point. You summed up your list of changes very succinctly: "everything". How could everything be wrong? And how do you know that? And the ultimate philosophical question: how do you know when you've gotten it right?

14185575322_850f5df71b_z.jpg
 
It's not a philosophical question. Anyone who does the same research I did gets to the same result. Really the only thing here down to philosophy or opinion more than just a little bit is tires; and even that is more based in concrete reality than some people who don't develop physics would like to think.

Usually, most of the things except perhaps the gear ratios and sometimes the car mass and well known things like the wheelbase are off in most simulation cars. The reason is basically lack of development time, data resources (Like for extremely old cars), and I am afraid sometimes some incompetence potentially.

Due to that reason I basically throw everything out and assume it's all wrong; often it is.

How do you know it's off? Well, have a good understanding of suspension, engine, drivetrain, aerodynamics, tires etc. for one. Decent mathematical prowess and ability to use Excel or something similar also helps.

Without it you won't have any of the means to examine anything intelligently, which includes partly just knowledge, but also some physical/mathematical calculations.

If you don't know what it is that you have, nor what you want, you might still be able to feel the discrepancy as a driver but it will be very difficult to do anything intelligent about it.


Well, to start off, after putting in some general values like the commonly listed mass, approx. fuel amount and position etc, I do suspension geometry first as it's the easiest aspect to do but also one of the most important.

The way you determine if suspension geometry is correct is by finding the basic angles of the assembly, like caster and SAI and putting those in to start. For whatever reason, every KS car I've looked at has wrong caster and SAI. You usually find them from the workshop manual and they're usually truthful, so I don't understand it myself. Error is often 50% or more.
It has nothing to do with tweaking steering feel; you do that by moving the whole assembly forward or back to account for the immobile contact patch in simulators and some other stuff, which can and will mess up feel in some geometries, like BMW's low-trail struts.

Then if you're lucky and there's good orthographic images of the suspension, a laserscan, a CAD model, curves in the workshop manual, curves someone measured, roll center height, arm lengths, *anything*, you start changing the points until you achieve the desired result. For these multilink suspensions it entails quite a bit of knowledge of the virtual pivots of the arms to go about that; you can't just average out the links and put it in.

Worst case scenario there's only images to go by, and you have to rely on your understanding of suspension to estimate.

For example if you know that your trailing arm has a 20deg sweep angle, you can calculate the camber angle change of the wheel for any given arm angle, and that will serve as a guide. You can use it to determine curves after converting arm angle to wheel deflection in your respective geometry.

If you're lucky like me, the OEM will just report the curves in their manual or advertising, like Porsche and Mazda did. They are usually truthful although I'm quite positive Porsche manipulated the droop side of their front geometries, as it is quite awful if real-world measurements by other people are to go by. Also comes out the same in the simulator, so it seems not even OEM data is always trustworthy.

Talking about OEM data, but these simulation developers don't really get anything serious, so it doesn't mean any of these professional made cars are any better than mods inherently. Perhaps a car mass, maybe some gear ratios. Doesn't seem like any curves or suspension geometry was shared to KS respectively, except maybe by Lotus, but I've heard they're quite cooperative.

Engine stuff is pretty much dyno curves and some understanding, differentials are sometimes reported by the OEM or aftermarket, often that's "just knowing" it, or converting a TBR from a torsen into lock % in clutchplate for example.

Aero too; sometimes you get a CD and CL, sometimes not. Sometimes you have CFD, but CFD is inaccurate, so that's not definite either. It's all "guessed" for a large part except perhaps if you get a full aeromap for all orientations based on good data.

Setup ranges; sometimes manual has it, often you need to reverse engineer it or just measure it yourself. For the NSX I found precise min/max angles achievable via adjusting; for most other cars it's largely just down to reverse engineering and logic. Every car will have a bit different tolerance anyway, so...

Car inertia, CoG height, weight distribution and mass; if you're lucky to get the true values, great. Often you get something super general that's not very true, and need to dig deeper. For the FD3S I found inertia, CoG height and weight distribution from Mazda themselves; for most other cars, you don't. Exact mass is also not *that* important as just having +- 1l of fluids in the car will change it; so just try to find the best you can. Often sim cars have loaded mass or dry mass, when it should really be wet mass but with no fuel and only one 75kg driver, for example.

Tires, sometimes you have data for some things, often not. Tires are hard to measure. A lot of it is just stuff "we know" backed up by some data, some of it is pretty arbitrary and tweaked with feel and logic.


How do you know your car is right? You don't. You only know how wrong it is. Simulation hardware and software isn't yet at the point where you can make a clear and radical statement about the accuracy of the simulation.

However physics is physics, and assuming the simulation works as intended (Not all aspects do, but most do) then the proper input results in the proper output. You can somewhat measure output with car telemetry for example, and compare that to the simulation. You can film video and compare those; although that's approaching more subjective areas. You can listen to the extremely unreliable thoughts of people who drive the car in real life.

I like to just look at the numbers, then drive it to see if it makes sense on paper and on-track.



That's the short version. :rolleyes:
 
I am having a strange issue which I don't understand. Despite this new car (whose physics I really like) being essentially a clone of the Kunos GT86, and the only significant change being the data file, I get a new interior so that for example the satnav screen no longer has a working satnav, it just has a generic screen, and the wipers no longer work properly. I am using Ilja's rain patch and with Kunos car the wipers both work to push the water away. With your physics, the left hand wiper doesn't push the water. What could possibly be causing these dfferences? I have unpacked the data with both versions, but can't see anything that could be affecting these issues. I would be grateful if it can be solved.
Thanks for your work anyhow!
 
I am having a strange issue which I don't understand. Despite this new car (whose physics I really like) being essentially a clone of the Kunos GT86, and the only significant change being the data file, I get a new interior so that for example the satnav screen no longer has a working satnav, it just has a generic screen, and the wipers no longer work properly. I am using Ilja's rain patch and with Kunos car the wipers both work to push the water away. With your physics, the left hand wiper doesn't push the water. What could possibly be causing these dfferences? I have unpacked the data with both versions, but can't see anything that could be affecting these issues. I would be grateful if it can be solved.
Thanks for your work anyhow!
That's probably because CSP is including a config for the KS car, but obviously not for this one. Perhaps if I find the KS car's config, I can include it as an extension folder with this mod in the future, if I update.

Perhaps you can find it yourself and make a custom config (Perhaps just copy the ks config and rename it to the correct car folder's name) to get those features to work again.
 
That's probably because CSP is including a config for the KS car, but obviously not for this one. Perhaps if I find the KS car's config, I can include it as an extension folder with this mod in the future, if I update.

Perhaps you can find it yourself and make a custom config (Perhaps just copy the ks config and rename it to the correct car folder's name) to get those features to work again.
Thanks, I'll try that
 
Yes that worked perfectly. Thanks
The satnav, as well as looking cool, is actually very useful. The wipers work properly now too. Thanks for your help.
 
The Minimum effective negative camber is around -3 degrees. How could I modify the file for more adjustment range toward neutral? Car Tuner app? I have not learned how to use it yet.
Setup.ini inside data.acd has camber adjustment ranges. They're referenced from design height, so check your *actual* camber values in setup, not the slider value.
 
Status
Not open for further replies.

Latest News

Online or Offline racing?

  • 100% online racing

    Votes: 78 7.0%
  • 75% online 25% offline

    Votes: 122 10.9%
  • 50% online 50% offline

    Votes: 163 14.6%
  • 25% online 75% offline

    Votes: 308 27.6%
  • 100% offline racing

    Votes: 442 39.6%
  • Something else, explain in comment

    Votes: 4 0.4%
Back
Top