You know, the nice thing about making roadcar physics is if that some people say they feel or think your physics are worse or better than someone's, they can always go and verify it themselves. It's not like flightsim physics where you can't just go and find almost any of the data.
I don't need to "prove" that my data replacements are objectively closer to the real-world equivalent than alternatives you there, if you do an hour of searching you'll figure it out yourself by noticing that almost nothing matches up on most alternatives.
To now the only argument I've seen from people who've never devved anything, like
@safi hellie, is something akin to "He is not a pro, so how can he make as good work as pros" or "I don't think it's realistic, so it isn't".
The more nuanced argument I've received from actual developers is that I'm working on limited, not fully reliable data, and thus my cars change somewhat from version to version and thus are difficult to consider as being "study sim" level products, like something akin to aphidgod's WRX or iER's P13C which has a more reliable data set used initially, from a more unified source. I agree with that, it's true.
Some cars like the (not yet updated) NSX have a large amount of manufacturer data now and are better for it, some like the E30 also have a similar amount of manufacturer data, but have other challenges like unsupported suspension types, or stupidly complex AWD systems, so your experience may vary. Either way there's no better *alternative* out there.
While I don't hold terribly large importance to it and prefer to stick to actual data and correct inputs, after all simulators are just tire force generators and there is nothing magical about it at all, most drivers of the real cars enjoy the ones I make. I really don't believe you have to drive a specific car to derive information about it, at most you can make extremely vague conclusions which can be a result of several factors interacting, but if you believe so, then at least this is something for you to think about.
More importantly, they all correlate very well to all of the good data which I do have, either be it because I got it from a good source or I calculated it myself with other good data.
Now I know someone will ask to post the data. My data folder is over 10gb so I don't think you want the whole thing but I'm happy to talk about physics and share data and the sources if you really want to (Arch#0819) but just to compare to some KS cars if you're truly curious, here are some easy to measure camber curves! The EX=0 versions of the geos diverge a tiny bit, but there *are* EX=2 versions at least of the FD3S. I don't think I ever built EX=2 E30.
Be sure to first align the car to the static values, and align it to the static height and do the measurement on a level surface, or in a geometry simulator. If you don't know how to do those, perhaps reconsider criticisms to begin with, and learn a bit more.
E30 rear, standard assembly, standard height, no driver no fuel
M3 rides 15mm lower, Sport Evo additional 10mm lower in the front, unsure if KS is accurate to that, doubt it.
Wheel travel vs deflection single wheel, degrees
Camber
+50.0mm = -0.275
+25.0mm = -1.15
+0.0mm = -2.0
-25.0mm = -2.875
-50.0mm = -3.725
Toe
+50.0mm = 0.31
+25.0mm = 0.24
+0.0mm = 0.23
-25.0mm = 0.26
-50.0mm = 0.36
FD3S rear, standard assembly, standard height, no driver no fuel
Wheel travel vs deflection single wheel, degrees
Camber, I think I derived droop side from simulation, not from the manuf. data as it didn't include droop, so you don't have to trust the droop side.
+40.0mm = -1.26
+0.0mm = -1.25
-40.0mm = -1.88
Toe, derived from simulation so you don't need to trust it, but it's what I built it on because it's sensible.
+40.0mm = -0.12
+0.0mm = -0.0
-40.0mm = 0.08
I know alignment curves isn't the only thing which matters and sometimes need to be sacrificed in some weirder geos for other aspects (Hell, the alignment changes mid-corner from suspension component deflection under G) but if you want to get an idea just what kind of inaccuracy we're talking about, do indulge yourself.