rear end feels unnatural

Discussion in 'Technical Archives' started by vilivili, Jan 12, 2012.

  1. Flaux

    Flaux Registered

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    Just some basics from my setup:

    - Springs: all "900"
    - Damper: all "1" incl. third spring under "advanced"
    - Anti-roll front: 47 (or 38 if I remember correctly. Depends on the grip of the track.)
    - Anti-roll rear: 10
    - Camber: 2.5 front and rear
    - Aero: "3" front, "15" rear
    - Ride height: "18" front, "30"-"40" rear


    So as you can see I'm really really on the soft side. Yesterday I tried different tire-pressures but it's not part of the basic setup to me, because it changes alot from track to track and from session to session.

    Also I found out that the car is completly different to handle at Estoril, where I was 2 seconds off the pace yesterday... so it wont get boring I guess. :)
     
  2. Doc_

    Doc_ Registered

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    There is nothing wrong with the rear end.
    Learn how to set up a car. This is a simulation. Not an arcade game.
    Basic set up help : http://www3.sympatico.ca/cbarnett/SetupMatrix.html

    Set up your wheel rotation correctly. If your wheel is too sensitive the car will be twitchy and uncontrollable.

    Practise, practise and more practise.
     
  3. Marco Boy

    Marco Boy Registered

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    I tihnk I can explain why the behaviour of any vehicles in rF1 is so 'innatural' but I cannot be sure if the same happens in rF2, but it is 'reasonable' be the same.....

    If you look at the TBC file (the only tyre file in rF1) there are five (and more but I will focalize these five) parameters that are very important for the tyre behaviour and that seems ISI and all modders ignore at all.... (sorry ISI but it's only my opinion and my feel after modify right them...)

    This example is from rF2 'rTrainer" .tbc

    DryLatLong=(1.260, 1.250) // Lateral/longitudinal coefficients in dry weather

    LoadSensLat=( -8.00e-6, 0.380, 21000) // Load sensitivity for lateral grip (initial slope, final grip multiplier, final load)
    LoadSensLong=(-6.70e-6, 0.580, 21000) // Load sensitivity for longitudinal grip (initial slope, final grip multiplier, final load)
    LatPeak=( 0.150, 0.225, 9900) // Slip range where lateral peak force occurs depending on load
    LongPeak=(0.110, 0.175, 9900) // Slip range where longitudinal peak force occurs depending on load


    Well, 1st line is an absolute parameter, just to set a kind of 'maximum' grip coefficient for tyre, lateral and longitudinal, usually the traction tyre shoud be a little bigger than other but it is no really important for our focus in this post.

    Most importat parameter are the third of the four line below.

    What means these?

    These are the dynamic behaviour of the tyre based on 'real time' weight (better MASS) they could support in a certain moment on track, the first is the LATERAL DYNAMIC max mass the second is the LONGITUDINAL max mass. Same for third and fourth but referred to STATIC (vehicles stopped). They are expressed in Newtons while the game use Kg and G to calculate all the weights...

    So that, we have to keep in mind that 1kg is about 9,81N of mass on planet heart at normal condition

    Any covered wheels vehicle could reach a least about 1,2G 1,3G lateral and longitudinal (not true, few concept cars reach these values) and an F1 vehicle could reach 4,5G / 5G lat/long.


    Well, in the rTrainer .HDV we can read:

    Mass=658.0 // (567kg empty) all mass except fuel

    Now, assuming we don't know how much G reach the rTrainer we have however this in game:

    21.000 (N) / 9,81 = 2.140 (Kg) / 658 (kg) = ~ 3.25G


    Ok... now if ALL THE OTHER physic parameters admit a maximum G about equal to calculated 3.25G we have an almost normal behaviour of the car, but, what happens if these values are set on a GT Megane????

    I have not here (I'm at work) the TBC file of Megane2009 but assuming that it weights 1000kg and like you can read on al lot of documents about the max G reacheable by a vehicle we could have (repeat, I have not the TBC file but i remember it is not much different...)

    21.000 (N) / 9,81 = 2.140 / 1000 (kg) = ~ 2.140G


    Poorly it means that you will have DryLatLong=(1.260, 1.250) till the G of the vehicle is under the max G admitted by the LoadSens parameters in TBC file, but your vehicle could not reach this G force and when it reach its max G it pass from 1250 to 0 suddenly.

    It is the 'centerboad' effect of a tire... the graphical deformation we have seen on the variuos video have to correspond to a 'real' deformation in 'in game' parameter....

    A tyre will deform and lose grip in proportion of its deformation, and you have to feel it on the steer, and this, in rF1, and i have some reasons to believe that it not happens in rF2 like rF1.

    In fact, in all rF1 mods (except the Grip modelled ones) you can't recover any suddenly spin by steer and throttle, but braking... and, please, but if you stop a wheel that has go off at the tangent is not the real way to recover from an oversteer....

    Ok... this post is long and maybe confusionary and I repeat, I can't confirm or not that rFactor 2 has the same behaviour of rFactor 1, but if you like what i have written try to modify these parameteres and see what happen....

    Of course these are semplificated calculation....

    Cheers

    PS. obviously, first times you use these parameters any car will results absolutely undriveable, because all of us are used to drive in arcade style, running any turns at unreal top speed and withous any effects of gradually loosing grip and, like said before, this is only my opinion based on my aknoledge and my experience :)
     
  4. Alric

    Alric Registered

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    Here, here!

    As a racing driver I must admit this is as close to real life so far! I was out at Silverstone last weekend and I had a huge 105mph slide which I corrected luckily, I went on rfactor2 the day after and over a bump at a similar speed round Portugal the same thing happened in the Megane and I thought to myself, wow this is pretty damn close now! In rfactor1 that kind of a slide wasn't 'catch-able' but now in rfactor2 it is, which is more like real life but at the same time not too easy to catch it. Well done ISI, the basics are there, it's just all the little niggles & content that need addressing now! :)
     
  5. patryksok.

    patryksok. Registered

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    Ok...but now we are talking about rF2, not rF1. rF2 does'nt use TBC file to tire physics, only for start temperature and rim size. In rF2 everything about tire is calculated dynamicly from real tire construction what you constructed in tgm file.
     
  6. jtbo

    jtbo Registered

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    Indeed, TBC is obsolete and even with rF1 tires have limited effect to unnatural behavior, there are so much else from suspension setup to inertias that make so much more effect. Wheel travel, bump stops, shocks, springs and inertias will make huge difference in handling, tires are only so much of effect really, sure they can be horribly wrong, but usually too much is put to their account and too little has been looked into other aspects.

    First link in my signature has some information about that part, most of it applies to modders of course, but understanding some of those things should help in making setup too.
     
  7. steve30x

    steve30x Registered

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    I cant feel the rear end of a car in a racing sim sitting on my computer chair. Maybe it feels unnatural is because you cant actually feel it.
     
  8. JvM

    JvM Registered

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    Flaux just wondering, can you tell me are you using default tyre pressures or more/less?
     
  9. Dany Mitchel

    Dany Mitchel Registered

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    It is not downforce you cant fix everything with down force
    try making a set up and I do not mean make one in 3 min
    take the time to put up a dedicated server and connect to it via local connection
    Online set ups can differ from ones made in single player normally online made set ups work in single player but single player set up normally seem of pace when driven in a online setting,

    Go to the link http://www.race2play.com/group/setup_tool and notice here you will find a tool to help you set up the car from
    information you put in

    This tool Is MoTeC for the Layman It is the Bible of set ups if you have no idea how to work MoTeC and once you can use MoTeC
    this tool along side it makes your set ups even better
    If this helped then Please click the little Star and add some reputation
     
  10. Flaux

    Flaux Registered

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    Stock 120kpa for Sepang. Still have to figure out a good value for Estoril. Did a quick trial an error yesterday and it felt better with 190 kps (full) but as the tire heats up, it loses grip. But I guess it should have more to do with the hole setup than with tire-pressure.
    But again for Sepang, yes, I use the default pressure.
     
  11. JvM

    JvM Registered

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    Thanks. :)

    The high pressure you tried, (if) too high cold pressure, and then loosing grip when they heat up, makses sense. So it might have been just that.
     
  12. Mechamorafa

    Mechamorafa Registered

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    Is it worth to work in setups already if the tire temperature is not reliable? In fact, how can I be sure if all the other parameters are reliable? I love to work on setups, but I'm afraid is a waste of time to do it in rF2 for now. Even in rF1 there was nonsense parameters.
     
  13. Flaux

    Flaux Registered

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    Hmm,...why not? It is a waste anyway because the cars will get an update before v1.0 I guess. But those 4 hours made my evening and it happened a couple of times that I started smiling caused by working changes on the setup. So,..go ahead. :)

    @JvM: Yep it makes sense :p


    @all: In singleplayer mode it took me 25 laps and one AI to get the grip for constant 1:47 laps. 46 and 45 is possible for sure...
     
  14. Mechamorafa

    Mechamorafa Registered

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    So basically you´ve set all the suspension parameters to minimum possible. I did that already, just to verify the possibility of driving the FR3.5 without boucing unrealistically on the track. It didn´t work. The grip increases a little bit but even with all the parameters at minimum the car still shakes a lot and loses contact with the ground on the bumps. Even if it had solved the problem, it would seem unrealistic to have to just set all to minimum to make the car behave properly.
     
  15. CdnRacer

    CdnRacer Banned

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    Can you post one of yours laps at sepang? Are you hotlapping or running race laps? I just started to try this car out last night and and I'm not noticing this bump you're talking about in turn 1. I'm quite far off the pace at the moment with that combination and I'm taking turn 1 at around 80km/hr I believe. I remember you mentioning 60km/hr so something is off there.
     
  16. Mechamorafa

    Mechamorafa Registered

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    My best lap is 1:49. Far from a really good lap. I can´t make this car stable and get enough grip to make a good lap. In youtube there is a guy who can reach 1:43. Use that lap as a parameter, not mine.
     
  17. CdnRacer

    CdnRacer Banned

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    Holy crap!! Personally I think a low 1.47 is a good lap. I figured 1.45 would be alien but 1.43?!!
     
  18. feels3

    feels3 Member

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    If someone from ISI is reading this thread, please try this mod :)

    Maserati GranTurismo.
    http://isiforums.net/f/showthread.php/5080-Maserati-Trofeo-GranTurismo-MC-Series/page2

    It behaves that how I expected from Meganes and Nissans, rear is very stable, car's reactions are very smooth and very predictable.
    Car feels very heavy and this is what I'm missing the most from Meganes and Nissans, also acceleration and braking are very natural and believable.

    It's not perfect of course, but in my opinion it feels very good.
     

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