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Formula-Retro drivability

Discussion in 'Automobilista 2 - General Discussion' started by Damian Baldi, Jul 2, 2020.

  1. Marc Collins

    Marc Collins Well-Known Member Reiza Backer

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    Thanks for posting--great race to highlight.

    I wonder what consistently ignoring the rev limit/up-shift light will do over a longer race (e.g., near end of video)?
     
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  2. oez

    oez Mayor of Long Beach

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    I was up to 14/100 engine damage after 10 careless laps around 77 Spielberg. So that I guess.
     
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  3. InfernalVortex

    InfernalVortex Active Member

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    Two thoughts - 79 feels wonderful. The Regular F-Retros now feel absolutely terrible. They wander so much more in a straight line and are very unpredictable. They just seem far more prone to being unsettled. The Mclaren M23 is the only one of the Lotus, Mclaren, or Brabham that I find reasonably driveable right now.
     
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  4. InfernalVortex

    InfernalVortex Active Member

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    So I did a 20 something lap race in the M23... Was great for 10 laps and became utterly undriveable after that. I normally race the Lotus, so Im not ssure if this is normal for the Mclaren or not. It seemed to be heating up the outside rear tire badly in our race at historic silverstone. What's curious to me is I had all my troubles at Abbey and at Chapel... those arent even real corners. When you do it right you dont even lift through there. But the car would just snap on me and dart off through them as the tires got hotter.

    Whatever they did with the diffs... it may be a step in the right direction but it feels terrible in that car right now.
     
  5. CrimsonEminence

    CrimsonEminence German localization/Testing Reiza Backer

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    Not everything has to be connected to the differential (actually the opposite, the diff is saving the cars a bit right now). This is more down to tire changes and might need some adjustments to default setup still.

    To counteract some of the issues, some recommendations for now:
    This was on the example BT44, but might also help for other F-Retro.

    Steering lock something between 21-24° (increases response to steering input, car is horrible with wheel input response, it will also not be so much more sensitive with gamepads, when increased)

    Brake bias 54-53% at the front

    springs rear 46 N/mm

    slow bump front 1667 N/m/s
    slow rebound front 2000 N/m/s
    slow bump rear 2333 N/m/s
    slow rebound rear 2667 N/m/s

    rear ARB 25 N/mm

    front ride height 54mm

    (And maybe a click less rear wing and 75-80° coast ramp angle)
     
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  6. Maser V6

    Maser V6 Old School. Enjoying AMS2.. ASSISTS OFF RACING Reiza Backer

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    Only from BT44 perspective and mine. (DFV cars imo all have a common 'oddness' to a greater or lesser degree.)
    Agreed, with the right direction, and given the swings and roundabouts since June 2020 seems to me & for me, after last tyre restore front grip, were going forward again overall.
    Race was fine for me tyre heat wise, I did dump all previous setups in folder and started afresh. as recommended in update I think? . (not set up for track and rusty there forgot how nice that track is).
    Thanks for reset tip. lol will remember that 1

    I tried the Lotus 79 at Monaco and the let's say 'oddness' is apparent there as expected.
    More enjoyment in both gen 1 and 2 atm, rather than 'leave it alone for a while' a few weeks back.
    Was kinda hoping to try one of your setups, so will try this 1.
    for the tightest of track these things ran on, say Monaco, any other adjustments/ difference in settings from above?.
    Ran the 79 wet at Spielbergh Historic last evening and feelt okey dokey, good, for some near future runs.
     
  7. CrimsonEminence

    CrimsonEminence German localization/Testing Reiza Backer

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    Lower preload, a good chunk of rake for the BT44, because it's actually producing a bit of ground and maybe venturi effect and a lot of steering lock and maybe even try to add more negative toe at the front. Be careful with rear toe, if you add some, it's abit quirky in AMS2 in general, but now, it shouldn't be that "sudden" and "edgy" anymore after the driveline tweaks.

    Shorter gearing will also improve the ability to turn.

    And one tip by me personally, that has to be executed decently though:
    Don't drive heel&toe on downshifts. Drive it clutchless there and control a bit of turn-in by strength of blipping, without grinding the gears. The disadvantage here is, to be accurate, or you will run into losing a gear or overreving the engine when blipping. But it's not that hard to do, maybe needs more attention into lower gears, but you should at least always be able to get that gear in.

    For the Lotus 79, but also Retros in general has to be mentioned, that at low speeds, you really need all the tire heating, you can get, it will probably be AWFUL in the first 2-3 laps, these tires need some good "breaking-in".
     
    Last edited: Apr 3, 2021
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  8. azaris

    azaris Active Member

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    Can't say I agree with some of the evaluations here. While on some tracks the default setups on the gen 1 might need some work (Brands is very tricky in these cars, for example), I was able to take the BT44 on defaults and run it through Nordschleife on the first try. I didn't see any of those hairy moments that used to plague the lap, where the car would just suddenly leap sideways and fly into the barriers (starting at Flugplatz). At the same time, it felt more lively and definitely required more care getting on the throttle and negotiating fast corners. The low-speed understeer is still there, but that's just a feature of this era of (fundamentally flawed) cars.

    The Lotus 79 in comparison feels like a grip machine in medium-fast corners.
     
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  9. oez

    oez Mayor of Long Beach

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    This thinking is something I contributed to in January perhaps. I no longer think the diff is to blame for absolutely everything as has been proven by updates to other components. But it does still play an indirect role and especially hairpins got much easier as there’s minimal last minute unlocking going on.

    One thing that does happen is if you force liftoff oversteer or otherwise turn in with a (in this given situation) completely locked diff, you’re not relying on a completely planted rear. It has to give in, slip and slide, for there to be that subtle extra rotation we want. And it always feels a bit sketchy going this route with the rear sliding. So in that sense it is connected to difficult handling from a setup point of view. You are forced to setup around the current diff behaviour. No matter your own taste or driving style. This is the part I don’t like. I still have fun though.

    I find that you have to force rotation with the F-Retro and a bunch of other cars to turn quickly. But this is quite safe to do, because the car wants to keep going straight and it no longer catches sharply with a nasty pendulum effect. Former likely in big part due to the LS diff. I assume the latter is tire and driveline improvements.

    So yes. I agree that the current LS diff situation helps keep the car going straight in this case. I can’t imagine an otherwise unstable or misbehaving car without heavy coast locking. It would be terrible.
     
  10. CrimsonEminence

    CrimsonEminence German localization/Testing Reiza Backer

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    No, actually i meant the exact opposite.

    The diff is making the car turn better at coasting/braking right now, also visible on wheelspeeds, the F-Retro doesn't look particularly unreasonable anymore, especially when receiving additional help by engine compression. Try some corners in Neutral or with the clutch and then with applied gear and without clutch.

    Again: Not everything has to be differential related. These understeer problems also have other sources and it shows more and more.

    A functional differential will also only work, if it has something to also actually react to.
     
  11. Maser V6

    Maser V6 Old School. Enjoying AMS2.. ASSISTS OFF RACING Reiza Backer

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    Yes the cars are nice to run there now and have moved on from Strangest reactions. glad your having fun to.
    .
    Mm RL sim or both. Flawed?
    Although the video posted earlier here at Laguna Seca shows the driver pushing the car at certain points, mainly straights, and no surprise given the value of the heritage beast.
    There is very little on board footage of drivers in the day actually racing the machines.
    What is crystal clear for me and from what I've seen and refered to many times is the lift off throttle. In the mentioned video and all others RL. when the driver lifts off for a turn, the retardation of car is immediate due to initially engine braking. If we had the same track and did back to back at the ie corkscrew then in sim we would have to wait for engine retardation to effect transmission line, trail brake overly /brake earlier, etc to compensate. (AI in sim similar corners will soon catch u up as they have no issue with this laggyness albeit improved)
    Careful viewing of the vid shows and is heard what happens on liftoff.
    This reaction from the car to pedal inputs contributes to the understeer effect in my perception and slows me down in an unnatural way.
    My rl cars are the same, 1 has throttle damper (and lag to lift off effect on transmission as a result) the other car slows immediately.
    Things have so much improve though, and it's nice to see this thread with a string of positive comments not seen before. looking forward to seeing more good comments and more people enjoying the Retros.
    I have enjoyed both BT and 79 in recent days here:):)
    The plan this season is to have some onboard footage and thoughts from our contributing (discussion wise) RL driver of the cars in question. (Covid permitting on this seasons schedule)
    In interview with a racing driver pt 3 in due course.
     
    Last edited: Apr 3, 2021
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  12. oez

    oez Mayor of Long Beach

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    Ah gotcha. You are probably right. I did notice that aggressive downshifting helps as revs shoot up in a lower gear. I will check telemetry. Even so it seems a bit suspicious to me that it takes a lot of engine braking to achieve unlocking, but that’s LS diff detail or something else. But you are correct in your statement and this may be why it feels safer than before as the rear isn’t sliding. Which is what I meant in my post even though I mistakenly said that the Retro slides when rotating (this is how I managed to drive them before) :).
     
  13. SaxOhare

    SaxOhare Well-Known Member Reiza Backer

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    The Retro Gen2 doesn't seem to like coasting, keeping the brake on, or applying the throttle in the corners makes it cornering easier.
     
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  14. oez

    oez Mayor of Long Beach

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    I tried the BT44 at 75 Silverstone. This seems half true. I did get rear diff unlocking in T1 except on my fastest lap (I forget how I drove through it then). But never in T3 even though it felt like it many times. I have a feeling that this should be easier to turn in, but I'm not sure. Low gear, high revs, engine brake, steering input... very stable. Either way this car feels entirely dependable and consistently fun to drive now so that's good news.

    Now to be clear from my side: I dunno what causes this and I don't want to claim to know (anymore at least). But I'm not seeing what you're seeing here and I can say as a driver that the car is hesitant to get turning. And even when it does turn it wants to straighten back up. My common sense says it doesn't help that rear tires speeds are locked together and those tires are massive. But this is just common sense - it's often wrong :p.

    I also wonder if my telemetry software (Second Monitor) is wrong somehow and it's not displaying data correctly.

    bt44_diff_ams2.jpg
     
    Last edited: Apr 3, 2021
  15. F1Aussie

    F1Aussie Active Member

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    Had a drive of the lotus 79 tonight, great fun. The car has understeer at low speed but when you have power slides you are able to drive through them. The complete opposite of the formula retro lotus, could not get that thing to go in a straight line or around a corner without wanting to spin out. I hope the lotus 79 in the retro 2 class does not get any treatment that makes it difficult to drive down the track.
     
  16. InfernalVortex

    InfernalVortex Active Member

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    I tend to disagree with this... I think if you look at the weight distribution of these cars the front/rear grip disparity may not be all that prone to massive understeer. But I can absolutely be convinced. The surface elements definitely indicate these cars would be prone to understeer. I just am not sure if they were anything like this bad in real life on corner entry where the front tire just seems to have so little grip.



    I cannot drive these anymore. They will not go in a straight line very easily... at least the 72. There's a weird resonance or something where the car sways back and forth oddly and will "snake" down the track. The M23 doesnt seem to do this for me, which is weird, but I had a bad race in the M23 yesterday just due to overheating the rear tires. That's user error, but I never had a problem with that driving the Lotus 72 previously. I could deal with the swaying if the corner entry was good, but it's not. It's better... but you can tell it's still reluctant to turn in initially.
     
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  17. Maser V6

    Maser V6 Old School. Enjoying AMS2.. ASSISTS OFF RACING Reiza Backer

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    I've reposted this vid here for several reasons. (in case you may have missed it.) From 'sim racing general discussion and thoughts' thread.
    Plus its interesting
    Ground effect ie Lotus 79 era, and new car F1 2022
    Johnny comments on understeer, ground effect seat being forward etc
     
    Last edited: Apr 3, 2021
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  18. InfernalVortex

    InfernalVortex Active Member

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    Wow what a beautiful car!
     
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  19. InfernalVortex

    InfernalVortex Active Member

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    This video just went live on youtube, I believe this is steelreserv on here.



    Note at 10:30 the differential discussion.
     
    Last edited: Apr 3, 2021
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  20. oez

    oez Mayor of Long Beach

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    By the way hitting the outside curb at 75 Silverstone in a powerslide in these F-Retros is so satisfying. Kind of like a mini game of its own. :cool:
     
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