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Released Trackfab Superlite 1.1

Lightweight track focused roadster

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  1. RobertGracie

    RobertGracie
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    Well glad to have provided some help with the Clear Cache fix :)
     
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  2. Crazy Killer

    Crazy Killer
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    yeah well... but about the weight, i just write it because i was having fun with this light car
     
  3. fufsgfen

    fufsgfen
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    There is something odd with engine braking settings of SL180 variety, 2nd gear engine braking is almost like pulling the handbrake and 1st gear engine braking with turning gives handbrake effect, haven't checked if that is drivetrain or engine friction being relatively high, but with this light car it feels quite excessive engine braking that makes driving more challenging than excepted.
     
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  4. TrackpadUser

    TrackpadUser
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    Any specific variant doing that? I haven't noticed anything out of the ordinary. If you have a video that'd be even better.

    Pretty much all the powertrain settings have been pulled from the 200BX, so engine behavior should be pretty much the same.
     
  5. fufsgfen

    fufsgfen
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    I'm not the best driver for sure, but can usually manage as can be seen(500hp RWD SBR4), other clip is Assetto Corsa sunday driving:


    I'm quite certain there is something terribly off in tires or engine torque side of things in BeamNG and your light vehicle with BX200 components just manifests these issues easier than some heavier vehicle would.

    For example, you can pretty much dump the clutch at 2nd gear with BX200 and it just throttles on, you can climb easily very steep hills with idling, not touching throttle and if you dump the clutch against tree on gravel, BX200 will spin wheels like on ice, or actually easier than on ice.

    You can do a burnout against wall with 35hp Autobello, using half throttle and 1500rpm, with ETKi 3L model that is 1100rpm and 15% throttle and it spins tire forever at that, which is quite insane if you think about it.

    Somehow engine wants to spin at speed X and tire friction is like 100 times smaller force than in reality not able to make much difference to engine speed, also when tire starts sliding it loses gigantic amount of grip compared to reality, this is not because your work, but because something is off in Beam currently.
    It may be tuneup of tires/engines in BeamNG or some issue in physics, idk.

    Clearly though one part of the issue is that as slip increases, grip keeps just falling more and more, while in realworld there is drop, but it does not continue to drop to 0 friction, drop is not like 50% unless on ice or tire become a liquid, so I would think that results tires not hooking up, add some oddities in engine rpm / throttle behavior and I guess issues come from there.

    I did only some 5 hours of different experiments, so it could be something else too.

    Also I'm not to bash anything here, just pointing out findings that appear to show something being off which may require some investigation by those who are capable of examining such things.

    I can only test thing and show thing, there is no way anyone could replicate this IRL, tires and engines just don't work like this:
     
    #125 fufsgfen, Nov 9, 2019
    Last edited: Nov 9, 2019
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  6. TrackpadUser

    TrackpadUser
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    Alright, I've actually re-read your first post, since reading the forums before my morning coffee is visibly a bad idea.

    Your problem seems to come from a mix of problems related to the SL170's poor setup as well as incorrect driving technique.

    It has fairly soft dampers, which work with the teeny tires and engines of slower variants, but it causes a lot of front/back body movement with the wider tires and more revvy engine.

    Add to that the LSD and not super grippy tires, and the reverse torque from downshifting w/o rev-matching (which isn't something you should be doing), causes some interesting handling, especially if you downshift mid-turn (which is also incorrect technique). Downshifting mid-turn isn't an issue with the cars in your two driving videos since the DCT transmission downshifts pretty much instantly and rev-matches for you, so it barely upsets the car.

    If you use the manual transmission throttle assist, it doesn't act like pulling a handbrake anymore since it rev-matches. It's still a bit dodgy however from the excessive front/back body movement due to the overly soft dampers.

    I'll put some more work in the setup, it's on the list of variants with fairly bodgy setups, and since it's not a meme tier variant it deserves some proper work. I've noticed the rev-limiter was set wrong as well o_O
     
    #126 TrackpadUser, Nov 9, 2019
    Last edited: Nov 9, 2019
  7. fufsgfen

    fufsgfen
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    Never I had tested this 620R car, but I thought I try to upset it and see what happens:


    Exact same track surface, which every same bump, 300hp variant which should be pretty equal match to above:


    Even with just lifting up throttle you can upset the car, that is when transitioning from throttle to brake, without touching brake it can loose rear end grip, but even more so, just driving at higher rate of speed it can pretty much end up to wall without much provoking.


    I remember when I made light vehicle and noticed that 0psi was perfectly good pressure, having more just made tires too stiff to grip.

    Now I know my heel and toe is not perhaps the most perfected, but IRL on track only dumping clutch like a good moron have ended me sideways in a snap, here I'm struggling with just lifting up the throttle.

    Another thing that makes going around these troubles is that there is not much in terms of skidding sounds in 0.17 version of game, when tires make noise, they are well sliding already and it is way too late to do anything about it.

    I hope 0.18 brings in some proper tire scrubbing sound, especially braking would be helped a lot with all cars if you could actually hear when tires start to skid, also after breaking traction.

    It is also incredible easy to keep tires spinning currently, with ETKi that is 15% throttle at 1200rpm, that is contributing also to this handling issue as it is very easy to get small slip to happen which then just keeps increasing.

    That affects all vehicles really, with lighter ones it just happens easier it seems.

    Changed to open rear diff for SL300R and then tested what is smallest amount of throttle tire keeps spinning, turns out 8% of throttle at 1500rpm is enough to keep tire burning
    upload_2019-11-9_23-7-51.png
    I doubt that IRL with race tires this would happen, but this is odd thing in BeamNG, tires just don't hook up when slipping this much, then no skidding sounds to warn, little need of suspension tuning being off and perhaps something giving bit much torque to wheels from engine side, that makes it very challenging to have this car to handle like IRL thing.
    I think supercharger added friction to engine too? Friction from diff, gearbox etc. adds up, so it might get to be bit much for such low amount of traction those tires have.

    Maybe adding two fat Stigs is in order, after all, driver is big part of this vehicle's weight and affects weight distribution considerably, just a node to seat position and another for passenger, maybe an option? :p

    I came up with this for now for SL300R:
    Damping front
    Bump:1850
    Rebound:3550

    Damping rear
    Bump:1500
    Rebound: 3100

    Antiroll:
    Front 22000
    Rear 8000

    Not sure if that is improvement, 2nd gear engine braking, turn in and rear end escapes even not particularly high rpm and it is not turning so well, would need less front ARB, but all the friction of drivetrain and engine just is quite bit compared to limited grip available from tires and cornering anything lower than 4th is risky.

    This was with open rear diff:


    I would think that adding driver/passenger weight and tampering with friction of engine/drivetrain could improve handling a lot.

    Still issue with how tires behave in game and throttle opening simulation resulting max torque with quite low throttle openings in some situations is probably going to cause behavior to be more extreme than IRL.

    Sorry about book, but there are lot of interesting effects in play here that might be good to brought up so that great mod would have chance to be even greater.
    Yeah, I think there might be need for some improvements in game in order to this light vehicle to work perfectly, one can work around by tampering with values and such, but it is bit of a hack then.
    --- Post updated ---
    I did tamper with friction and engine braking values, most definitely those are major part of the issue.

    Also did tamper with suspension settings and that can help a lot, it is almost manageable after all those changes, just no skidding sounds in game and tires giving up completely after a point which is issue no one but devs can improve upon I guess.

    Glass smooth tracks it is so much easier, with bumpy surface all the challenges just skyrocket to new level.
    --- Post updated ---
    Yeah, I think that I pretty much fixed what could be fixed with it, behaves much closer to what one would except now:

    SL180R in camouflage, more or less, lift off snap does not happen anymore.
     
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  8. TrackpadUser

    TrackpadUser
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    Part of the issue might be caused actually by the setup not really being meant for a track as bumpy as the Nurburgring. It's mainly been tuned for the vanilla race tracks, which are fairly smooth. They're also fairly oversteery compared to the vanilla cars which for the most part seem to have loads of understeer.

    I will agree however that the SL300R is a bit sketchy even on nicer tracks. This might be related to the larger tires and/or higher speeds compared to the SL180R. I'll try to investigate a bit more, but the issue is that it's at a point were it can get hard finding the exact reasons for unwanted suspension deformation behavior, since the JBeam acts decently well most of the time.

    I'll also do some tests with the damper/ARB settings close to those you listed, which are a decent bit softer than the current setups.

    For the engine braking issues, I've looked into it a bit, and there seems to be a few parameters that might affect engine braking. I'll try taking a hack at it later, and I'll be reading a bit on theory to try to see what it should be in terms of values. One thing I'd love to know, mainly by curiosity, is exactly how the vanilla values where defined.

    For the supercharger there doesn't seem to be a true "Friction" parameter, however my guess is that the crank loss parameter causes some additional friction, possibly slightly raising engine braking.

    As for weight, I am not sure it really is the issue, since as previously stated, the SL180R handles fine IMHO, other than the fairly oversteery setup and hard dampers which may cause issues on some tracks.

    Thanks for the feedback, and for sending me down a googling rabbit hole about tire physics and engine braking torque. :D
     
  9. fufsgfen

    fufsgfen
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    For a quick hack, I just halved differential friction and engine braking torque, I think I took down engine friction down to 8 from 13 too, but you might want to experiment with those, it still has that lift off characteristic that allows thing to turn in nicely, similar to Porsche's and this thing has slight rear weight bias.

    It is really fun car to drive, supercharger might be just over the top for those tires, at least without tire scrubbing sounds and my lack of skill that is! :D

    Another thing I noticed was that maxing out Toe in and pretty much same for camber made car much more predictable, even negative camber should in theory help with cornering here it seems to cause rear end to loose traction quite easily, not really sure what that is about.

    Anyway, it does seem quite much better with little tampering, while not being boring too easy to drive thing.

    Last thing I remember is that 1st gear is bit short, I set that so that when launching from stand still, when first rpm led lits, drop the clutch and you get perfect launch, you can see how on some old race cars RPM gauge needle starts moving only at 4krpm or so, you got good launch when dropping the clutch as needle starts moving, just perfect amount of wheelspin.
     
  10. TrackpadUser

    TrackpadUser
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    I'mma do like anyone does 5 minutes before
    I'mma do like any good sim racer does 5 minutes before a race and ask if you've got some setup files to share ;)

    I know Toe-In at the rear helped a lot during the inital tuning of the car. The thing was sketchy as hell before that.
     
  11. fufsgfen

    fufsgfen
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    Sure I have, but would you like to have suspension calculation formulas from Koni dampers made into spreadsheet to calcluate proper starting point values for mod cars one happens to make?

    Might take hour or so to get stuff sorted to your PM, can't send everything in that spreadsheet thanks to legal things, but might help you some anyways ;)
     
  12. TrackpadUser

    TrackpadUser
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    That sounds great, I've currently been using some random ride frequency calculator for the spring stiffness calculations, along with essentially eyeballing the damper stiffness.
     
  13. Kasey1776

    Kasey1776
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    Awesome!
     
  14. TrackpadUser

    TrackpadUser
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    I'm currently doing some minor changes, including adding an RHD option as I'd like to make this thing a tad more British.

    upload_2019-11-21_18-55-10.png

    I've been thinking about changing the car's name to "Blackpool Superlite", giving the manufacturer a more british name, and keeping Trackfab for offroad racing stuff. I've been wondering if people had other suggestions/ideas.
     
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  15. default0.0player

    default0.0player
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    What's the meaning of "Trackfab"?
     
  16. jerrie

    jerrie
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    Seems like a good idea. Maybe make trackfab a subbrand, like the blackpool trackfab buggy.
     
  17. RobertGracie

    RobertGracie
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    I see it more styled after a Caterham Seven myself, maybe call it the Leicestershire Three?
     
  18. FLyInG 2 YoUr SoUL

    FLyInG 2 YoUr SoUL
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    In a Lotus-like nomenclature, this shoud be the One, since it's the first model produced by the (fictional) manufacturer, Two at best if we consider the older Autobello-based buggy a canonical model.
     
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  19. RobertGracie

    RobertGracie
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    Reasonable point to make I suppose :)
     
  20. TrackpadUser

    TrackpadUser
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    It's short for "TrackpadUser Fabrications". And as said previously, I plan on keeping it as a "brand" that build offroad racing vehicles.
    This mean the autobello buggy, as well as my WIP class 1 buggy and other projects of that sort I'd like to do at some point.

    The autobello buggy will keep it's current name, the Superlite is the only one that's getting changed. And I'm not planning on changing the name "Superlite" itself, or copying an other manufacturer's naming scheme. I'm just looking for a more british sounding brand name.
     
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