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Throttle / Pedal Issue?

Discussion in 'Assetto Corsa' started by Shaun Clarke, Aug 11, 2017.

  1. Shaun Clarke

    Shaun Clarke
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    Hi All,

    Just wondering if somebody you help me. As you will see by the video, I apply very little throttle, but get maximum revs. This happens in Official cars and tracks as well as mod cars.

    I have re-calibrated everything, and it works in AC/Settings/Controller screen ok, but in game, as you will see.



    Cheers

    Shaun
     
  2. Manfredk2

    Manfredk2

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    Which pedals?

    Had a similar issue with Fanatec CSP V3 (full rev without touching the throttle). Solution for me was to save the preset for axis/FFB/keys in content manager again.
     
  3. Shaun Clarke

    Shaun Clarke
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    G27

    I never start the game from CM, only from AC Icon
     
  4. PhilS13

    PhilS13
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    That's normal, nothing to fix on your side
     
  5. Shaun Clarke

    Shaun Clarke
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    Oh thanks for that, so not "show" progressive pressure then...hmmm major fix there required

    Thanks again

    Shaun

    PS - I only spotted it now, as I was sending a file to a real racing driver trying to show the progression of pedals, matching revs, speed, as I never use this view, and just spotted it and I thought, what have I broken, bust tested official car and track and found out, it's not my mod
     
    Last edited: Aug 11, 2017
  6. PhilS13

    PhilS13
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    It doesn't affect the car while driving. It's probably only missing the throttle losses which would only show up at high rpm low load.
     
  7. Shaun Clarke

    Shaun Clarke
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    It does affect the car actually, when you trying to measure throttle pressure to power. The Throttle.lut file, you state, 100 % pressure is 100% power, but in fact 25% pressure is 100% power, makes it harder for us modders to get is correct
     
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  8. PhilS13

    PhilS13
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    Ok but no it does not mean in fact that. Try actually driving the car with 25% throttle and see how fast you can go maybe?
     
    Last edited: Aug 12, 2017
  9. kunos

    kunos
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    so let me get this straight...you think that a car should reach the max rpm at 100% gas pedal while standing still, and if it doesn't in means it'll have "max power" at whatever % pedal you need to reach max rpm... and because this does not happen in AC you think there's a "major bug" that should be majorly fixed.

    Have you ever had a real car?

    The guy in your avatar just did a 360 in his tomb... and so should all the people that made through the daring challenges of high school.
     
    Last edited: Aug 12, 2017
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  10. Rupe Wilson

    Rupe Wilson
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    gotta love the customer support :thumbsup::thumbsup::thumbsup:
    Maybe you could explain why and enlighten us lesser mortals as to why, and help the guy out as apposed to poking fun please :)
     
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  11. kunos

    kunos
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    ya my bad for thinking this stuff should be pretty obvious... here we go then, sit down and enjoy a dynamics 101 lesson:

    RPM is a measure of VELOCITY.. just as km/h or m/s... RPM is the velocity at which the engine is rotating.
    Gas pedal influences the amount of fuel (and obviously other things like air opening and fuel mixture) that goes into the engine and that result in TORQUE.
    TORQUE is is a FORCE.

    FORCE generates ACCELERATION.
    ACCELERATION over time generates VELOCITY.

    So let's start very simple, how much force is needed to accelerate a cube to 10 km/h ?
    ANSWER:
    Any force >0 will do , so given enough time, even a force of 0.00000000000000000000000000000000000001 in whatever units you want is going to give us, eventually, a velocity of 10 km/h.
    This is obviously counter intuitive here on planet earth but it's totally true in space, that's actually the reasoning behind things like solar sails.. the idea is exactly that, it doesn't matter how much force you can generate, even a very small one over a long period of times will give you astonishing velocity.
    Here in earth tho, we have to deal with all sort of frictions that will try to slow down every moving object to an halt... there are different kind of frictions, to simplify we can say that the friction that comes from air and liquid is dependent on speed (ie.. the faster you go, the bigger is the force trying to stop you).. and the one that comes from contacts (ie. tyres or scraping against a wall) that is more constant regardless of speed.

    So once the basics are covered let's consider our car engine.
    This is an engine that is able to produce enough torque to get a 1000+Kg vehicle and all it's rotating parts (gearbox, diffs, wheels) up to whatever max speed it can by resisting air resistance that is trying to slow it down... so after all, it must be pretty damn powerful right?
    So how much of this power is really needed to get just the engine up to its maximum speed?
    An engine with disengaged clutch only has to overcome frictions coming from the engine itself.. and those frictions will also be there when the car is in motion.
    So, if an engine would need max power just to make it to max RPM with disengaged clutch.. would it be able to get to max rpm once the entire drivetrain is engaged and the actual car is moving?

    So what amount of torque the engine really needs to produce in order to get to max rpm? Just enough to overcome the friction in the engine itself. Being and engine a kind of "air pump", internal frictions are mostly coming from compressing air, so they are velocity dependent (ie.. the faster the engine goes the more friction there will be).. this what we identify as "engine brake torque"... it's much higher if the engine is at high RPM right?
    But we are still talking about a fraction of what the engine needs to overcome in order to move the entire car and the rest of the drivetrain.

    So finally, does the engine need FULL POWER to simply overcome the internal frictions? Obviously not.. or, as Phil suggested, if you are not convinced and you still think that since RPM max is hit with 25% gas max power is obtained at 25% gas.. go on and drive with 25% gas and see how fast you'll go around a track.

    To make it brutally simple, RPM is NOT a measure of power, is a measure of velocity and has no (independent) relationship whatsoever with the amount of power an engine has or hasn't. At the end is simply an equilibrium between engine torques and friction torques.. as long as engine>friction the rpm will go up.

    oh and btw.. this has nothing to do with "customer support".. unless you expect the head of a studio to give physics lessons to somebody reporting a "bug" because his Mustang in game can't pull 4 lateral G in a corner.
     
    Last edited: Aug 12, 2017
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  12. Eddy

    Eddy
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    Awesome explanation Stefano :)

    One thing I'd like to add, in real life, at least on my bike , let's say I'm doing 7000rpm, then slowly start pulling the clutch in without changing the throttle then the revs will start climbing, maybe not to the extreme of 25% but maybe it'd eventually hit max rpm given time, I imagine the same happens in a car but never tried in real life
     
  13. Rupe Wilson

    Rupe Wilson
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    thank you :thumbsup::thumbsup::thumbsup::thumbsup:
     
  14. Shaun Clarke

    Shaun Clarke
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    Thanks for the lesson @kunos (Stef), and yes, I do have a real car thank you, a very nice one in fact.

    @Rupe Wilson Don't worry, I have known him long enough for his sometimes, tonge in cheek replies, and I never take them to heart, actually made me smile, esp his reference to the cheeky chap in my avator doing 360 turn. Wonder how much pressure that would of taken :roflmao:

    And OK, my bad. I hated physics @ school, at the time, wasn't interested in the rotational gravity force of the solar system....Now if somebody told me back then, that physics would apply to computer sims, then maybe I would of paid attention. :(
     
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  15. RasmusP

    RasmusP
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    Awesome explanation from Stefano. Reminds of when I ask my physics lecturer at university how a LCD screen works (I just wanted to know how the crystals are actuated) and after 20 minutes I knew how it's build, what problems you get, how light bends through little holes, about the two models of light explanation (beams and waves) and why we need quantum mechanics to understand them together :confused::roflmao::thumbsup:

    To give Shaun a quick answer: I need about 5mm of throttle in my old 120 ps c-class to reach about 5k rev and 1-2mm more to reach the limiter.
    As Stefano explained: the explosions from the fuel only need to work against the internal friction of the engine, which is reeeeeaaallyyy low :)

    My thoughts why it feels strange on the Logitech pedals: as everything on such "cheap" pedals, you have nearly no feeling for the first 50% of the pedal. They are too light and too less friction. Plus you don't feel the Torque of the engine when you push the throttle. In real life you feel a little kick/notch coming from the engine into the chassis :cool:
     
  16. Shaun Clarke

    Shaun Clarke
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    I have uprated springs, so I have really good feeling, it was just me being a total....
    [​IMG]

    I actually went and tested this in my Focus ST, as I just never thought of it like this. I actually thanked Stef for the lesson, as I told him, his 10 second reply made physics sound interesting, instead of the 5 yrs I suffered at school:)
     
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  17. RasmusP

    RasmusP
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    Haha that picture :laugh:
    Yeah it's a shame that there is no time in school for interesting examples. But instead of kicking some stuff out and make it interesting, they cut out the fun part :thumbsdown:
     
  18. HypoToad

    HypoToad

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    I use them without shoes on, just socks, it lets me feel them beautifully, but you are right if I am wearing shoes I get very little "feel", but my solution works well until I get some better pedals.

    Comparing real cars and going back to my first car, it had non assisted drum brakes, so I literally had to push so hard on the pedal it pushed me back into the seat, then I got a car with power assisted disc brakes. I would nearly go through the windscreen until I got used to them. You also needed plenty of upper body strength to steer my first car and it had a huge dead spot so you had the wheel going from side to side to keep it going straight.

    My latest car has drive by wire steering and is so light and direct, but I love it, and the brakes don't need any pressure at all, so it's horses for courses, depends on what you are used too.