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Vintage formulas drivability

Discussion in 'Automobilista 2 - General Discussion' started by Jonathan Spencer, May 3, 2020.

  1. CrimsonEminence

    CrimsonEminence CrimsonCringeLord Reiza Backer

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    Maybe i will try a full length AI race with them and see, how far i will come, before i die and looking if tyre pressures actually peak at some point. :D
    Did you ever ran into a moment, when the pressure was stopping from rising more and more?
     
  2. Damian Baldi

    Damian Baldi Active Member

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    Sometimes if tires goes over 1.80 bars after you spin the car (or just by staying at track in neutral), later driving again with some speed pressure stabilizes at 1.65 bars. However, the tires at 1.65 are almost undriveable and that's the main point of all this.

    If you want to maximize the pressure problem, try at slow tracks at sea level, where the engines have their maximun power and tires can't release the pressure by rolling fast. Adelaide, Londrina, Snetterton, Curitiba, Goiania, Guapore.

    At mid speed tracks like Kyalami (where engines only have 360hp instead 410), Spielberg, Imola, the problem is not so noticeable, or it takes more laps to happen because there are long straights.

    Another interesting point, is that tire heat and pressure seems to be not related that's very extrange. Just stop the car on Adelaide and wait, tire temp will remain the same, but pressure will rise fast.
     
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  3. CrimsonEminence

    CrimsonEminence CrimsonCringeLord Reiza Backer

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    Yes, i've seen this often in AMS2 in general now.
    The tire temp, indicated in the HUD should be the tyre surface temp, though. I have no clue how brake temps into tyre air emission is influencing the whole deal without checking some telemetry or what else is influencing the workwise of this system. I asked about it in another thread, but got no answer.^^
     
  4. Damian Baldi

    Damian Baldi Active Member

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    I made new tests at Adelaide and I have to say that it looks like the pressure rise doesn't come from the track, but from the brakes. What I made was, go out from the pits with 1.20 bars pressure, stop at the track and see what happen. The pressure increased really slow, and took some time to reach 1.21 bars.

    Then I made two laps and pressure rised to 1.44 (front) 1.47 (rear) bars, then I stop and saw how the pressure rised more and more until reach 1.84 (front) 1.80 (rear) bars. Pressure rised more at the rear tires while driving because friction, but once the car was stop front tire pressure rised faster than rear, and I think it was thanks of the higher temp of the brake discs.

    Going out
    20200723014914_1.jpg


    After lap 1
    20200723015317_1.jpg

    Staying after 3 laps
    20200723015521_1.jpg
    a minute later
    20200723015613_1.jpg

    another minute later
    20200723015705_1.jpg


    The results shows the same, slow tracks make pressure rise faster than fast tracks where tires release pressure while rolling.

    ----------------------

    Another test was to go out from the pits and spin the car making donuts. Rear tire temp rised up but pressure didn't move much.


    20200723020243_1.jpg
     
    Last edited: Jul 23, 2020
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  5. InfernalVortex

    InfernalVortex Active Member

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    These cars are great, but this proves the tire model is just broken on these.
     
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  6. CrimsonEminence

    CrimsonEminence CrimsonCringeLord Reiza Backer

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    Thanks for testing this!(!!)

    I already suspected that yesterday. But this should be partially normal behaviour to a certain amount, because the energy is going into the tyres directly over the rim, core-, air- and rubber- temps in the tyre remain/rise and pressure is adjusting to that. Pressures should also rise due to surface heating, though (the Donut example), or i'm baffled and need an explanation, why it isn't happening. :D

    (Tyre temps on the surface often are lower and if the HUD shows this value, then it's not that meaningful for pressure, but just a hint)
    BUT: Is it maybe a bit too much? There is quite a journey going on from 1.2 to almost 2 bar. :D

    But believe me, when i say, that the F-Vintage aren't the only car, influenced by this behaviour, it's basically a general behaviour in AMS2. I've seen it happening also with other cars, i saw on videos and also driven by myself in AMS2 and so on.
     
    Last edited: Jul 24, 2020
  7. Damian Baldi

    Damian Baldi Active Member

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    I think that heat transfer from the brakes to the tires should be part of the equation, but as it is today it overshadow everything else. I mean, no matter what you do with the car, heat transfer from the brakes is everything that matter as physics are now. I exploited this today doing the fastest lap at Kyalami by almost a second in TT. What I did was to do the first lap slowly without touching the brakes, and then I started the second lap having a clean acceleration from the last corner with tires still under 1.3 bars and bingo.

    What I mean with this hotlap example, is that physics as they are today doesn't represent true racing, it's more about adapting to a problem. Real racing in part is that, better adaption, but in this case I feel it's extreme.

    On the other side, this exagerated heat transfer, narrows the posibilities to explore different setups and driving styles, making the winners those whom found the way to mantain tire pressure controlled. All this is very far from what I expect from racing.

    About AMS2 in general, this situation should be fixed or modified to bring a better racing experience. Tires are fundamental, all you do to the car, and all the responses from this planet to the car goes throught the tires.

    About the Vintage cars, this situation is something terminal because the driving style needed puts a lot of stress on the tires. The easier solution in the short time, is to reduce brake's heat and to add a lot more heat inertia, to balance heating on low and high speed tracks (now are on the extremes). Other solution is to directly reduce the heat transfer from brakes to the tires (but I don't know if the engine allow this kind of changes). Last solution is to make tires to work better at 1.5-1.6 bars.

    Vintage cars in particular had very weak and primitive brakes. I think any cheap car of today have better and more powerfull brakes. Solid discs and a single piston on the caliper, that convination can't generate so much heat if brakes are exposed.
     
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  8. Damian Baldi

    Damian Baldi Active Member

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    Careful with this solution, because it could create a bigger exploit making the tires superfast with low pressure. Reducing brakes heat and reducing cooling should be the path, because disc would need more time to reach high temps, and then there shuldn't need a fast and high cooling. This solution avoid temp peaks.
     
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  9. David Wright

    David Wright Active Member Reiza Backer

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    The 1967 Lotus 49 originally had ventilated discs with 4 piston calipers. At 305mm dia they are larger than the 256mm dia discs on my cheap car of today. The Lotus 49 was unusual in mounting the brake discs so that they were just proud of the inner edge of the wheel rim and so exposed to the airflow. The ventilated discs were later swapped for solid discs as the ventilated discs did not get hot enough for the racing spec brake pads, which did not work well unless the discs were hot.

    I am not commenting on the general issue you are discussing (do the brakes have too much influence on tyre pressure). This is a new aspect of the physics for Reiza and its certainly possible they haven't got it perfect yet, but your general assumptions about historic brakes are flawed. When a racing car brakes from say 170 mph to 50 mph, the kinetic energy in the car is largely translated into heat energy in the brakes. This is true whether the car is a 1967 F1 car or a 2020 F3 car. It is not true that just because brakes are older they will generate less heat.
     
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  10. Damian Baldi

    Damian Baldi Active Member

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    Good information about the ventilated brakes. Brake discs temps is the result of contact surface, pads pressure and their abrasion. I can't say what's the correct value in these cars. More disc diameter doesn't mean better braking if the pads have the same surface, but it better for disipation.

    EDIT: I was wrong about diameter. More diameter means that the pressure is applied farest from the wheel axle and it should be more effective.

    Most of the car I had check have only two faced pistons and solid discs. Only the BRM P83 had ventilated discs with what it looks to be four pistons, maybe because that car was very heavy
    These are the discs and calipers of the Matra MS11 - Rear

    upload_2020-7-26_15-48-25.png

    Front
    upload_2020-7-26_15-49-1.png


    Cooper T86 - Rear

    upload_2020-7-26_15-49-46.png

    Front

    upload_2020-7-26_15-50-50.png
     
    Last edited: Jul 26, 2020
  11. XTRMNTR2K

    XTRMNTR2K Active Member Reiza Backer

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    Throughout Early Access and most post-1.0 versions, the Formula Vintage (G1) has always been the bane of my existence. No amount of fiddling with the setup could make this a car that I could honestly say that I truly liked and understood. The basis was there, but for every bit that I enjoyed the car would exhibit at least one or two odd quirks that didn't feel quite right to me.

    Now that I've finally found the Formula Retro to be amazing in the latest updates (thanks to updates to the tires among other things, iirc) I also decided to give the F-Vintages another try today. For this I chose Hockenheim '77 as track - my first run on any of the Hockenheim versions since the DLC has been released. (I realize '77 is not fully era-accurate for the F-Vintage, but it's the closest I could get for now).

    Even with the default setup, the car (G1M1) suddenly made much more sense to me. It didn't radically switch between under- and oversteer so much any more, and despite the squirrely behavior under acceleration and braking it was quite fun. So I decided to dive into the setup for a bit.

    Ultimately I reduced the differential ramp angles to ~58-60 for power and 45 for coast, as well as increasing the number of clutches from 4 to 6 or 8. This made the vehicle feel much more planted under acceleration and when lifting off the throttle, while still enabling throttle (and brake) -induced steering where necessary.

    Additionally one of the first things I did was reducing brake pressure to around 81-82 percent while also further moving the brake balance to the front (between 64/56 and 52/58). This resulted in vastly improved braking behavior. No more silly lockups at high speed, or veering off to one side or the other while approaching a corner!
    In order to keep the brakes somewhat cool I would also further open at least the front brake ducts to 60 or 70 percent.

    For the V12-powered Model 2 it also seems to help if you increase tire pressure from 1.6 to ~1.65 bar in the setup for all wheels. From what I could tell the V8 actually seemed to be more stable at 1.6-1.62 bars of pressure, so it's probably better left alone unless you really need that extra pressure.

    (Oh, and both cars also needed some adjustments to the gear ratios. The V12 in particular suffers from gears that are waaay too long, losing a lot of its power advantage even on fast tracks like classic Hockenheim)


    So, now that I had gained a decent grasp of the G1M1 and M2 I finally tried the G2 cars for the first time. Way back I had promised myself I had to get a good grasp of the '67 F-Vintage before even considering the move to the '68 ones.

    This time around I already had a decent idea of the setup changes I wanted to make, so I was good from the get-go. And what can I say - they are amazing! A tiny bit slower on the straights, just a little bit more prone to understeer throughout some of the corners, but definitely just as much fun as the first generation! Wow.

    I've already dismantled my racing setup for today, but the next time I get an opportunity to spend some time with AMS2 I am definitely doing a race in one of these!
     
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  12. Damian Baldi

    Damian Baldi Active Member

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  13. Damian Baldi

    Damian Baldi Active Member

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    Talking about the brakes again, and putting aside that the brake ducts not changing the cooling, the main thing is the overall thermal inertia, or que speed of heating and cooling.

    As the brakes works now, it's ok at some tracks, where the brakes stabilizes at an operative temperature near 500 ºC. The problem appears at slow tracks like Adelaide, and Londrina, where brakes stabilizes near 600 ºC and all that heat is transfered to the tires rising their pressure.

    The goal should be to find a thermal inertia that permit the brakes stay on their operational temp, or below a temp that doesn't increase the tire pressure so fast.

    I don't know how it could work better, if with slower rising temp and lower cooling (maybe), or with the same rising temp as today but with faster or more effective cooling. That's the devs task.
     
  14. lawgicau

    lawgicau Active Member

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    Just wanted to check in and say thanks for a great race online with Damian today in these cars. In practice I started about 7 seconds seconds off his pace but slowly improved enough that we could have a great 10 lap race. He was still at least half a second quicker than me but the battle was fair and fun. :)
     
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  15. Damian Baldi

    Damian Baldi Active Member

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    Ohh is that you, you had a great rhythm. I made a mistake and spun the car. I pushed the car as much as I could but it was too late. I usually host races at the same hour as today, join us, you drive very well.
     
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  16. Marc Collins

    Marc Collins Well-Known Member Reiza Backer

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    This was even more insane than a H-16. As is evident by the exhaust, it is actually two H-8's pancaked on top of each other!! Oh, to remember the days when the teams could be creative and come-up with truly innovative engine, transmission and chassis designs...
     
  17. lawgicau

    lawgicau Active Member

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    That timeframe is mornings in Aus, so on weekends I will try to join.
     
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  18. Damian Baldi

    Damian Baldi Active Member

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    Here is a lot and very detailed information about the Repco-Brabham cars from 1966 to 1968. Even there is information engine by engine and by number, power curves, etc etc etc

    The Brabham BT26 announced yesterday used both engines Repco 860 and Corsworth DFV, this information could be usefull if the engines used is the Repco.

    Repco Brabham Engines – primotipo…


    And here, detailed information about the BT-24

    Give Us a Cuddle Sweetie…

    Even if numbers don't care you, the overall reading is very interesting.
     
    Last edited: Aug 1, 2020
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  19. Damian Baldi

    Damian Baldi Active Member

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    After release of v1.0.2.0

    What a great news is to have these two new cars. Both feel very different, with the Lotus being a lot more stable and the Brabham more agile and nervous (at least with the early setup I was using). I can't confirm with any data, but the engines feels different, less agressive making the driving better. The Brabham doesn't have suspension animation, but I think it's just a question of time.

    The generic cars with the new tires and smaller rims looks better, and they seem to have a better interaction with the track, I mean height and tire connection from the graphic point of view.

    It looks like every cars has a different seat position now, needing an adjustment everytime you jump from a car to another. Was that in purpouse or it's a collateral damage?

    Now the most important thing. Tires. Physics seems and feels great while the cars run with tire pressure between 1.25 and 1.45 bars, over that pressure everall handling change and become diffuse, with the car too nervous and slippy tires. Brakes seem to work as before causing that overheating.

    Abother thing that desn't make sense with these cars, it's the increase in tire pressure before the race. I understand that hot tires/brakes avoid accidents at T1, but it seems to work better with modern cars instead these vintage ones.

    Commond point is still the same, the best performance of the cars is always the first lap, then everything become worse at every lap.
     
    Last edited: Aug 12, 2020
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  20. BrunoB

    BrunoB Active Member

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    I have not checked this out mainly because Im solely running AMS2 in TT/LB mode where tire temps doesnt matter (so much).
    But if the tire temps in AMS2 is mainly caused by transfer of brake temps and to a (much) lesser degree dependent of the rubber/tarmac friction then the correlation is plain wrong.
    But even without knowing exactly how the AMS2 tire model is constructed I would not conclude that the TM is broken - but maybe more conclude that the correlation between tire temperature raise caused by brakes vs tire friction is wrong.
     

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