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(DATA REPLACEMENT) BMW M3 E30 Improved Physics by Arch 1.8

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17.02.2020 Version 1.8

- Added M3 E30 AK01
- Added 325i E30
- Added 325is E30
- Redid both rear suspension layouts
- Changed Sport Evo dampers
- Changed M3 rear spring to "Late" type spring as per 1987 data
- Found more accurate damper travel ranges for E30, M3 from BMW manual
- More accurate motion ratios for sta-bars from BMW manual
- More accurate steering ratio for M3 from BMW manual
- More accurate E30, M3 front geometry
- Changed S14B25 rev limit from 7250 to 7800 as per new data; old seems to be B20
- Changed setups for tuned cars
- Removed crash bolts from Sport Evo
- Small suspension tweaks, corrections
- Corrected wheelbase, tracks in M3
- Tire tweaks to falloff, relax length that I forgot
- Changed masses to account for strut unsprung mass bug that I forgot
- Changed UIs

04.02.2020 Version 1.7

- Added Drift version
- Derived more accurate front sta-bar MR
- Adjusted wall thicknesses for sta-bars
- Moved trail axis of front suspension forward to combat issue with steering forces
- Figured out E36, Z3 etc. steering racks, refitted to S2 properly
- Minor tire changes
- Maybe minor suspension changes that I've forgot

04.12.2019 Version 1.6

- Implemented custom load curves to tires
- Tire tweaks
- Changed ARBs and ARB setup
- Changed M3 front knuckle geometry
- Changed rear toe deflection
- Changed brake bias
- New aero
- Added yaw drag fin
- Reverted S2 to stock M3 rack
- Bunch of small suspension changes, spring angle multiplier etc.
- Updated UIs

13.10.2019 Version 1.5

- Adjustment for damper oversight
- Calculated rollbars
- Changed rollbar setup design for tuned cars

27.09.2019 Version 1.4

- Reverted DTM rollbar links to "rubber" from "solid" due to new evidence
- Tire changes
- Changed throttle graph

26.07.2019 Version 1.3b

- Changed S2 steering rack from Z3 to E36; slower

22.07.2019 Version 1.3

- Lowered DTM tire rates by 20%
- Tweaked DTM tire grip falloff values which I forgot
- Different camber sensitivity values for tires
- Tweaked angular inertia for tires
- Changed unsprung masses to probably more accurate values
- Added camber adjustment to stock car via strut dome bolts
- Expanded S1 camber adjustment due to ^
- Made "poly bushing" lateral deflection effect stronger on S1 and S2

14.07.2019 Version 1.2

- Added S2 version
- Changed M3 E30 DTM 1992 damper bump characteristic
- Changed M3 E30 DTM 1992 suspension stroke characteristic
- Added nice description to DTM car
- Minor tweaks in inis and whatnot, mainly for modders

12.07.2019 Version 1.1b

- Changed M3 E30 DTM 1992 ARB range and adjustment based on new data
- Changed M3 E30 DTM 1992 damper range and adjustment based on new data
- Changed M3 E30 DTM 1992 rear camber and toe range and adjustment based on new data
- Changed M3 E30 DTM 1992 default setup to mix of Group A manual and common settings

11.07.2019 Version 1.1

- Added M3 E30 DTM 1992
- Changed undertray ground height sensitivity
- Adjusted graphics offset 1mm forward

09.07.2019 Version 1.0b

- Re-measured front suspension with more care
- More accurate track widths/offsets
- More accurate alignment
- Changed S1 alignment design from camber top to OEM parts

08.07.2019 Version 1.0

- Release!
- Added S1 version
- Added ST and SM tires
- Adjusted rear lift coef. from 0.7 to 0.8 (Compared to base model E30) based on new data
- Fixed big aero issue with front lip, oops! Thanks @baker7498
- Minor tweaks
- Added optional CSP features config, thanks @Leonardo Ratafiá

07.07.2019 Version 0.9e

- Completely new aerodynamics from the ground up
- Suspension tweaks

06.07.2019 Version 0.9d

- Added new engine(s): original curve courtesy of @mike12345678
- Tweaked tire very very slightly

05.07.2019 Version 0.9c

- Changed rear geometry slightly, rear bumpstops, front ARB, brakes, FFB among others

05.07.2019 Version 0.9b

- Changed bumpstops, height, rollbar, ARB, dampers, alignment, FFB among others

04.07.2019 Version 0.9

• Initial release


Doesn't require shaders patch! CSP functions and 3D aero changes require shaders patch!


BMW M3 E30
BMW M3 E30 Sport Evolution 2.5
BMW M3 E30 Sport Evolution 2.5 S1
BMW M3 E30 Sport Evolution 2.5 S2
BMW M3 E30 DTM 1992
BMW M3 E30 Sport Evolution Drift
BMW 325i E30
BMW 325is E30

Physics and custom UI file by Arch/Kyuubeey
UI file torque curves by x4fab's AC Torque Helper
Everything else by Kunos Simulazioni
Special thanks to:
@baker7498, @mike12345678, @Leonardo Ratafiá among others
for data and help
@Matt for helping with Drift version
@kondor999 for testing and feedback

Donation link: paypal.me/ArchKyuubeey


The data.acd file is intended as a replacement used alongside the KS BMW M3 E30 visuals
or a fitting visual of your choosing. Visuals and sound are not bundled with the package.
How to install:


M3 = KS M3 E30 and KS M3 E30 sound
Sport Evo = KS M3 E30 and KS M3 E30 sound
S1 = KS M3 E30 and KS M3 E30 sound
S2 = KS M3 E30 and KS M3 E30 sound
DTM = KS M3 E30 DTM and KS M3 E30 DTM
Drift = KS M3 E30 D and KS M3 E30 D
E30 = KS M3 E30 and KS M3 E30 sound

Installation instructions

make 8 new folders on content\cars:

copy from folder bmw_m3_e30
all these files to the new previously created folders:

copy from folder bmw_m3_e30_dtm
all these files to the new previously created folders:

copy from folder bmw_m3_e30_drift
all these files to the new previously created folders:


Extract and replace all from the downloaded file


Extract folder "extension" to Assetto Corsa directory

Latest updates

  1. Rear geometry, normal M3, E30s, fixes

    17.02.2020 Version 1.8 - Added M3 E30 AK01 - Added 325i E30 - Added 325is E30 - Redid both rear...
  2. Drift, sta-bars, steering feel

    04.02.2020 Version 1.7 - Added Drift version - Derived more accurate front sta-bar MR -...
  3. Load curves, aero, ARBs, setups

    04.12.2019 Version 1.6 - Implemented custom load curves to tires - Tire tweaks - Changed ARBs...
  4. Dampers, rollbars

    13.10.2019 Version 1.5 - Adjustment for damper oversight - Calculated rollbars - Changed...
  5. DTM ARBs, tires, throttle

    27.09.2019 Version 1.4 - Reverted DTM rollbar links to "rubber" from "solid" due to new...

Latest reviews

Those comments regarding your physics being innacurate in comparison to kunos cars must be pretty annoing :) Some people just can't get over the fact that they like kunos version better, not thinking about how that feeling was achieved through some unnatural and tricky phisics parameters :)
Finally the cars are great to drive! Impressive improvement over the previous versions.
So much better, many thanks!
Fantastic improvement. I can only really speak for the base model US -spec M3 and the 325is (both of which I've driven), but I feel like you've nailed it this time. Both cars are delightfully neutral as you approach the limit, and will react properly to throttle inputs as you do so. Conversely, If you're sloppy with your inputs or lift at the wrong time, they'll bite you. These are my new favorite road cars.
I prefer the kunos versions at this moment
Certainly not an improvement over the stock KS M3. Only 2 stars because we have already have an excellent E30 M3 from KS. I really think you should put the books down occasionally and get out there and drive a real car, to help you refine what they actually feel like to drive. You will never learn that from a book. I drove a Schnitzer-modified E21 323i in competition from 1984-1986 in SCCA D production, and have driven US-spec street E30 M3's on several occasions afterward. These cars were beloved for their adjustability with the throttle, but your version (I tested only the street car with 90's tires) has eliminated much of that essential, defining characteristic from the car. Instead, it is only slightly reactive to sudden throttle changes, which is *quite* wrong. These cars still had the old semi-trailing arm rear end and were quite a handful on the limit (though the M3 was masterfully tuned). As a result, the cars IRL would often require maintenance throttle to keep them from over-rotating mid-corner. The KS version reflects this. Yours does not. I don't really care if all the angles and arm lengths etc are "correct". The end result doesn't match the real car. Why not get a real driver to help you with your correlation problems? You have them, regardless of what your books tell you.
I've got a lot of E30 and M3 driver feedback. All of it is contradictory with each other. Half of them say it should oversteer more, half of them say it should understeer more. I have some ideas myself though; I don't think it's in the rear necessarily. As they say, if there is a problem in the rear; look in the front.

If you want to help me, you can record some footage and send it to me via PM and describe in detail what you think the discrepancy is. I could get a better idea for the underlying issue; if there is one. Sta-bar mount flex is certainly a possibility.
Hi, I don't know what you did to this car the feeling is very bad, the one of kunos is a reference in simulation...
You killed a myth!
First of all I want to say that I have a direct drive so the level felt is not better at the moment.
I also own a BMW (not a DTM of course) so I know how these cars behave.

With your data I no longer have any feeling in my steering wheel, I no longer feel the oversteer or understeer and the car really stalls for nothing. It's confusing because I feel like I have a Logitech, it's really ridiculous.

Okay, I've never driven a DTM, so how can I tell if I'm right or wrong?
I can't but I think that if Kunos doesn't necessarily have real value it's to compensate for these lack of feeling let's not forget that we're in a video game everything is not 100% perfect.

I think the BMW kunos look pretty much like the real ones, especially the production models.

PS: I would like to say good things about your work I know what it is and the Temp it takes especially as I appreciate your RUF but here we are really wrong.
You can press "+" on the numpad if you want higher FFB.
S1 is really fun, will try others mods from Arch for sure !
DTM is so good! Thanks.
how do i update from one version to another, without doing all the initial installation process?

If you have the car folders already made, it should be as simple as just dropping all of the car folders in the download into content/cars. It will only replace whatever is in the update, so data.acd and ui folder. The sound, 3D and everything will be intact. The only exception is if car folder names change: as of 27.09.19 only the FD3S has had it happen many updates ago.
Again, you are not in a position to "improve the physics" of any official AC car. You didn't drive these cars IRL, you don't have nearly as much real life track experience as AC devs, nor do you have nearly the amount of data they have, as they are licensed by the manufacturers to create these cars.

You should NOT release these as "improved physics" but "my taste of physics." Improving the physics of a car is little more than changing a few lines of code and making it easier to drive.

As I outlined in my earlier reply, that sentiment is largely false. By doing things like comparing the simulation's outputted suspension angles in the provided developer apps and referencing them against a workshop manual, or perhaps a real measurement, you can find that the cars I have worked on indeed feature incorrect values and I have brought the values closer.
By acquiring schematics or measurements of suspension geometries and comparing them to the original versions, you can indeed determine that the placement of the links is wrong. You can also verify this via comparison of suspension camber and toe curves, for example, as the kinematics of the suspension is derived from it's geometric shape. This car in particular, the E30, is perhaps even over 50% incorrect if the rear suspension is concerned, at some amounts of wheel deflection.
By acquiring things like engine torque curves from a dynometer and comparing them to the Kunos curves, you can indeed determine that mine are numerically closer on average.
By acquiring things like differential lock % statements from manufacturers, and measurements/manufacturer statements of differential preload, you can determine that they are wrong and I have improved on them.
For something more specialized like the ATTESA E-TS system in the Nissan Skyline GT-R cars, you can output the AWD2 lock value from the simulator via a real-time graph reading, and compare it to onboard telemetry of the ATTESA system's center case pressure and indeed determine that my output in similar conditions is closer than the Kunos implementation.

If you prefer mine or not is or if you believe the end result is closer or not is a different matter, but on average it is somewhat difficult to argue that my cars are input number and simulation output number-wise farther from the real values than the original car.

PS: What did you think of any of my cars? You can post in the "support" section.
Just love the work you've been doing withKunos cars.
Just drove the S2 version around Nord. really challenging car, but I find the it a little too loose/slippery, even with Slick rear tyres.
Thank you
Thanks. If you want a more neutral car, you could adjust the front ARB to maximum and lower the rear ARB until it behaves as you want.
Great update! DTM is soo good now.
Feels just like it was meant to, now we just need someone to fix the ugly Kunos E30 and we'll have a full car.
S2 is such a beast. Recommended to use the e30 drift engine sound. https://youtu.be/RgxQyLIV388
You are doing a fantastic job.
The DTM needs some work indeed.....

Thanks. I'm just following damper spec, so it's unlikely the DTM will be smooth over kerbs. It's just too stiff for the (lack of) downforce. The real dampers and spring have been described as being extremely stiff. I imagine the spec BMW provided is for smooth tracks and not riding kerbs. It's better if you lower the dampers and spring a little + lower the ARBs to the lower settings. 4hz is quite stiff after all. There's still a bit I can do with dampers though + stroke is a bit wrong, so it's needlessly stiff.
Road cars are fine but the DTM becomes unstable over the curbs in a suspicious manner.
Yeah, I'm taking a look at it. Sticking to BMW damper data is unlikely to provide a truly stable result: the springs are too stiff for that anyway. But I don't have accurate damper plots, so they are open to all kinds of change.
Another great mod from you. Thanks a lot!
drives and drifts great! keep it up!
This is one of the best mod I have seen so far in AC. Accurate rear suspension geometry build, E30 unique characteristic and the handling has been very well simulated. My second time in my life to give 5 stars rating
Thanks for your this cool mod and for your work!!!
cool car mod

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