I 100% cannot replicate this, I'm guessing you are able to do this because your gameplay setting are assisting in some way. This is how my driving aids are set and I can stall any vehicle in the game without issue.
This is because the backlash in the clutch is exaggerated. When IRL you slam into gear your engine will stall since the gearbox is not turning due to vehicle stopped. In BeamNG, the clutch "device" is like a torsion spring. When doing this, if the engine is heavy enough, the momentum might overcome the torsion spring of the clutch, thus not stall.
https://www.facebook.com/profile.php?id=100070664538346 Examples of proper vehicle stalling, or not stalling if flywheel weight/tire grip allow. Edit : It wouldn't allow me to post the video directly, it's on my Facebook page though.
one thing i would like the game to simulate is clutch juddering, like, when the clutch isnt exactly "new" or if the pressure plate has some unevenness, mainly noticeable when the clutch is slipping.. also, the clutch backlash is very noticeable in the Citybus manual transmisson, and the T series, since, well, giant engines.
I've disabled all my driving assistance settings. This is basically the behavior for the basic covet 30% of the time (other 60% is not so bad low speed sputtering but still not stalling and 10% it stalls). I did try out the Vivace and it does stall everytime when just releasing the clutch without any throttle. But you can still replicate this weird low speed sputtering/backlash by giving it a little throttle but which you'd expect to stall.
It'd be cool but I'm not even sure how you would develop a model that can produce uneven wearing of the clutch other than using randomness plus in realtime In the real world, no material is perfectly flat at the atomic level and no material has uniform density (some sections may have a hair more density than other sections meaning that some sections have different heat transferring properties) which is how uneven wear can occur. I think it'd be more feasible to simulate tire wear than clutch wear lol.
It should be noted that any modern engine ECU is automatically adjusting the trottle depending on engine load. I can drive my real life car up the step ramp from the underground parking in 1st gear with little issues at "idle" because the ECU will increase the throttle to the necessary level to avoid stalling the engine. It is easy to stall the engine when you stall it faster than the ECU can increase throttle. Slowly trying to stall it sees heavy fightback from the ECU that may put "the pedal to the metal" in an attempt for the engine not to stall. Nuff said, if you dont outright kill it, it just might keep going.
I haven't played BeamNG some time and I'm little suprised about clutch behavior in actual version (0.27). OK, so far, clutch seems to be working like should (shifting, going down/uphill). But (and sorry for my english), I can't calm down car from over/understeer. Even so, for example, I can do multiple skids very easily in racing(!) version of ETK1 driving 100kph on dry tarmac with clutch on. In case of some RWD cars after exceeding some speed without changing the (low) turning radius car slowly goes oversteer (loosing grip... too easily), so I turned clutch on and it has almost zero impact on gently starting oversteer skid. Well I often play on a gamepad (without the possibility of surgically precise response), so in this case, there is nothing to do (And yes, I have been using lower sensivity settings for higher speeds (and some cars are quite OK)). Take it as a suggestion, or I will be glad for advice on how to change the settings. But overall i really like the game and thanks for a great job!