1966 Brabham-Repco BT20 v1.6 Now Available!

Discussion in 'News & Notifications' started by 88mphTim, Feb 27, 2015.

  1. Sido Weijer

    Sido Weijer Registered

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    Both actually. At 80:20 you send 80% of the fluidpressure to the front brakes, and 20% to the rear. So compared to 50:50, you increase the front and decrease the rear pressure and thus braking torque.
     
  2. Lazza

    Lazza Registered

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    Ok, so it's probably safe to assume the BT20 brake torques (1996:1618) represent the torque when the bias is 100% at each end? So 50:50 would be 998:809. (that's a raw torque balance of 55.2:44.8, by the way)
     
  3. Damian Baldi

    Damian Baldi Registered

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    I don't know if you noticed the same thing. At Spa, when you are on the previous straight before the Masta kink, the horizon looks stable, car's body looks stable, but the wheels moves up and down like crazy while you don't feel anything on the steering wheel. It looks like the car is floating.
     
  4. Sido Weijer

    Sido Weijer Registered

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    Not really. As far as I know you just have to press the brakingpedal twice as hard to get an equal amount of brakingtorque at the front wheels with a 50:50 brakebalance than with a 100:0 brakebalance.
    It could be that I'm wrong though, might depend on what exactly determines the maximum braking torque. There are probably other people around this forum that can answer that better than me.
     
  5. Miro

    Miro Registered

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    Yesterday I had an cool 60's funk/soul playlist in my ears at Brianza and it was truly epic to race there.
    I am thinking all the time about how it would be with the rift. I can't even imagine it really. rF2 with the rift is gonna be an awesome experience.

    On the other note, I like this car.
    Has a very interessting limit IMO. The balance is aswell awesome. It really is insane to get a simcar to behave like this. Good job. Thx ISI.
     
  6. Marc Collins

    Marc Collins Registered

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    +1
     
  7. speed1

    speed1 Banned

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    I mean to know that there is something called balance bar which is connected with the main brake cylinders, and is a rail with which the ends are connected with the push rails of the main cylinders, where the brake pedal presses on the middle of, the driver can shift the brake balance, while he shifts the point in which the pedal presses the balance bar to controle the twin main cylinders, and i mean this is possible by a gearshift in the cockpit which is connected with a cable with the balance bar.

    Streatcars regulating brake pressure distribution by the ABS or statical by a pressure distribution cylinder such as in older systems to find on the rear axle as example, the also can controle fluid pressure distribution variable relative to the axle load, but wth is the value 57.xxxxxxxxxxxxxxxxxx with the three million numbers after the comma ? Apples ? :p What my question was all about.
     
    Last edited by a moderator: Mar 3, 2015
  8. P.S.R.

    P.S.R. Registered

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  9. Spinelli

    Spinelli Banned

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    Speed, think of it this way.

    If your balance bar, fluid pressure, whatever, was set to 50% front and 50% rear BUT your front brakes are super powerful brakes, grab very hard, don't fade, use a material with a TON of friction etc. while your rear brakes are TINY brakes made for my grandmother's bicycle, fade after 2 seconds, don't grab hard, use a material with low friction, etc., then, in the end, you'll surely be getting much more braking force at the front wheels VS the rears. So even though the balance bar and fluids and all that are set at 50:50, the end-result is not even close (in this example) to 50:50. Therefore, in my example, you could even set the braking to 30:70 (F:R) and there will still be more braking force, in the end, acting on the front tyres than the rears because of the physical properties/design of the brakes.

    I'm not sure how all of that fits into RFactor 2 and the Brabham. I know in RFactor 1 and even before (F1 Ch 99-02) brake disc thickness (or was it diameter?) could be set in the garage. Does RF also simulate calipers, materials for pads, and rotors? Or is there just a general "torque" setting stated for each individual wheel's brakes? I'm not sure, but how sophisticated or basic the end-result is calculated in RF2 shouldn't change anything anyways regarding this particular subject (Brabham brake-bias thing)
     
    Last edited by a moderator: Mar 3, 2015
  10. speed1

    speed1 Banned

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    That is clear, the value in the setup menue isn't as explained above. Actually it means Apples to me. :)
     
  11. Lazza

    Lazza Registered

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    Which value? The only one I can find is the actual brake bias setting. I can see you're asking about a number 57.xxxx, but I can't see that anywhere :(
     
  12. speed1

    speed1 Banned

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    That value is just an example for those in the setup menue.
     
  13. speed1

    speed1 Banned

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    Ahhhhhhhhhhhhhhh sorry for confusing you guys. Seems as if it was due to text colide. Now it looks quite logical and right after setting windows text size to 100% and no XP stile. The doble dot was lost and it looked like as a part of the 50 :eek:

    Now it shows 55.0:45.0 for the Brabham, before it looked like 55.0450 or something like that. :p I need a break. Thanks to all, it at least was a quite intresting talk.
     
    Last edited by a moderator: Mar 3, 2015
  14. Lazza

    Lazza Registered

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    lol

    It's funny how 'simple' stuff like that can be so confusing and cause all sorts of discussions... at least you worked it out :)
     
  15. speed1

    speed1 Banned

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    Shame on me or my machine playing tricks with me. :)
     
  16. Emery

    Emery Registered

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    For anyone having trouble getting consistent lap times (or having trouble completing laps), make yourself a setup. My own setup transformed what appeared to be a twitchy car hellbent on killing me into a car I can comfortably drift at high speeds (whether I intended to or not, LOL). Took me several sessions to get there, final adjustment was tightening up the front shocks so long corners didn't result in washing-out into understeer. Now all I do is adjust gears for new tracks... well, usually, as some tracks are grippier than others, so minor balance tweaks occur.
     
  17. P.S.R.

    P.S.R. Registered

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    Ironic that I am coming here to post this right after Emery's post above but I was sincerely coming here to ask if anyone but me wonders whether there the slip is too forgiving (my layman term). In other words the tires feel like there is almost no limit to how you can slid them they never break free (another layman term). What I mean I guess is that I feel that I should be spinning MORE. Damn I have this car so sideways it's insane. I'm not complaining because the car is great to race and still challenging to go fast but man I have a very loose setup and I honestly don't know I just feel like I am getting away with too much it's that simple so I was just wondering if I am the only person on earth that feels that way and/or if maybe next set of tire model updates could make it (OK, more?) challenging again or if this is realistic I'm totally OK with it because I am having an insane blast with these vehicles and I have no real world experience on bias ply tires on a race car. Anyway, just wondering...
     
  18. Emery

    Emery Registered

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    In the USA, from about 1990-2005, autocrossers in certain classifications often relied on a Hoosier bias-ply street tire. It drove kinda squishy, a bit slow to bite, but, man, the things you could get away with! Mid/rear-engine drivers often had the tail hung out at extreme angles. There was one X-1/9 couple out of Seattle area who liked their car extra loose and you'd see the tail hang out 30-45 degrees to direction of travel. The tradeoff to driving that way, as you'd expect, is wear & tear & too hot for best traction.

    Eventually most folks started using the radial version, but the bias-ply is still listed (http://www.hoosiertire.com, Sports Car DOT Bias in the catalog).
     
  19. P.S.R.

    P.S.R. Registered

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    Alrighty then. Makes sense. Thanks :)
     
  20. David Wright

    David Wright Registered

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    Although normally driven very tidily, if you do a Google image search for the BT20 you will find images of this car being driven at extreme angles of opposite lock without spinning. Brabhams were very user friendly cars, and Jim Clark reported that the 1967 Goodyear tyres (which Brabham used) were much more forgiving than the Firestone's he normally used on his Lotus 49. It is likely the 66 Goodyears were forgiving too.
     

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