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Performance Model 3: Excited or Disappointed?

Discussion in 'Model 3: Driving Dynamics' started by GTKAZ, May 20, 2018.

  1. Garlan Garner

    Garlan Garner Banned

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    Reguardless - over 2 years ago....Tesla / Elon said the car would be 35k and today its still 35k.....even though they haven't started building SR yet.

    https://www.bing.com/videos/search?q=model+3+elon+talks+finance&&view=detail&mid=C7097ACFA1A27831A21EC7097ACFA1A27831A21E&rvsmid=9D82ECE24AA85ED693F99D82ECE24AA85ED693F9&FORM=VDQVAP

    I would like to know where the article is where he posted that a 60kWh car would cost 46.500 so that I can see what he is talking about.

    $35k was and has not been vaporware.
     
  2. McRat

    McRat Well-Known Member

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    Vaporware - A digital product that has been claimed 'almost ready' for a long period of time with no actual retail product to sell.

    Elon Musk publicly stated the 60kWh Bolt must lose $9000 per unit. That means the MSRP has to be at least $9000 higher, which would be $46,500. There is not a lot to a Bolt other than the 60kWh, 200HP drivetrain. It's maybe a $15,000 roller at best, so Elon thinks it's driveline is over $31,000.
     
  3. Skotty

    Skotty 2014 S P85 | 2020 3 P19"

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    It's as quick as cars like the V12 powered quarter million dollar Aston Martin Vanquish S. I think we're good.
     
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  4. Garlan Garner

    Garlan Garner Banned

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    The bolt? We are talking about the bolt now?

    Again....to respond to the thread title....I'm excited about the Model 3 itself. Disappointed about the performance price. Excited about the SR price of $35k as it was stated over 2 years ago.
     
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  5. Knightshade

    Knightshade Well-Known Member

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    Exactly as many as you are making.

    But unlike you they've actually physically torn down a Model 3- so they seem much more likely to have the slightest idea what they're talking about regarding its parts and cost- since they provided a somewhat detailed analysis of same- and you've provided... what someone tweeted about the cost of a totally different car...
     
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  6. bxr140

    bxr140 Active Member

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    It is a simplified version of the formula...and not simplified like Navier Stokes to Euler but more like something you'd learn in high school physics. It is very good at illustrating the top level concept and getting the first order answer, and specifically does that by hand-waving away of all the perturbations (which is exactly where things like the nuances of the braking system come into play).

    Since you posted it though we can still use it, because it actually does in fact support the notion of bigger brakes being better anyway. See that "f" in the equation? That's the coefficient of friction. That's not a constant. In fact, that's where many of those pertubations roll up. Going back again to first year high school physics, friction comes in two forms: static, which is higher, and dynamic, which is lower. You see this all the time in life--its a lot harder to get something moving (Static) than it is to keep it moving (dynamic) . A rolling tire has no relative motion to the ground (more or less) and thus falls under the "static" realm. Conversely, a locked up tire is moving relative to the ground and thus is dynamic and has a lower coefficient of friction. Apply that to a car, and it explains why it takes longer to stop a car when you lock up the brakes than it does when the tires are just at the limit of 'still rolling'--the higher friction in the rolling tires enables more braking force. (There's even more nuance when you add in things like tire slip, but since that just supports my position even more we can skip past all that.)

    In fact all that is why ABS was invented in the first place--to better keep the tire near that 'still rolling' limit and not beyond into the locked up condition. As previously discussed we know that bigger brakes enable the ABS to more finely control the wheel speed; that of course will increase the amount of time the tire can spend near its maximum braking force, and that enables the car to slow down faster. An adjacent analogy to this point is taking two identical modern cars and magically replacing one car's ABS computer and control unit/modulator with units from, say, the 80's. Same tires, rotors, calipers, suspension, master cylinder, vehicle mass, etc. Both versions of that car will lock up the brakes and engage ABS in an emergency stop. One version of that car is going to stop shorter than the other in an otherwise identical emergency stop, and that's because (in this example) technology has enabled much finer control over wheel speed.

    Indeed, you're absolutely right that more force doesn't help once you've applied enough brake force to maximize stopping force. Nothing I've said suggests otherwise. Again, the value in the bigger brake is the additional control they provide. When ABS 'engages', what its really doing is relieving system pressure by a small amount over and over again very quickly. It basically lets off the brakes for a split second when it senses the tire has transitioned from static friction mode (rolling) to dynamic friction mode (locked up), which allows the tire to start rolling again and transition back to the higher friction mode. Importantly, that cycle is a function of the system's ability to control based on the inputs. Adding more control--like, by adding bigger brakes--reduces the cycle time and magnitude, keeping the tire closer to the limit and of course the result is that the car slows down faster.

    Make no mistake, I'm fully aware that this definitely does not move the needle on the first order answer. We're probably taking a few inches...maybe a foot at best. To that end I wholeheartedly stand by a statement like "bigger brakes won't really make a difference in an emergency situation on a modern car". It is the resolute insistence in turning that kind of first-order, hand-wavey statement into a binary truth that I find damaging in this kind of fourm. As it were, I'm a sucker for calling out misinformation. :p
     
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  7. Knightshade

    Knightshade Well-Known Member

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    So far so good... here's where you go off the rails...

    Except no, we don't.

    We didn't "discuss" that.

    You claimed that- and then when asked for sources to support that claim (which would be contrary to all the sources I provided) you failed to provide any- or even a physical explanation of how or why that would be true- instead you simply repeated the claim and pretended anyone "discussed" it.

    It would if somehow bigger brakes actually did that- they don't of course (and physically can't)

    I again suggest you re-read pulp friction.

    It explains what bigger brakes can and can NOT actually do.


    How does that help your point?

    That's due to better ABS sensors taking more readings more often and the computer controlling the system being improved- in your example the actual physical brakes are the same.

    So it's an incredibly weird way to try and suggest upgrading the physical brakes would do that since that's not, at all, what happened in your example.



    Except the part where you claim larger brakes help. Several times. Never once offering any evidence of that actually being correct- and in the fact of source after source telling you it's not.

    In court this is called "assuming facts not in evidence"


    Here again you provide a fairly accurate explanation then go off the rails with-

    This is utter nonsense you've once again provided no evidence for.

    How does "bigger brakes" let you come OFF the brakes faster (the bit you just described in ABS)

    We know it doesn't help fully engaging the brakes- since even you admitted more force once you have enough to lock the wheels does not help.

    So coming off is the only bit left in your story.

    How, specifically, do "bigger brakes" help you REMOVE braking force quicker?


    Or it's zero. Because that's what even the people who sell big brakes say it is. Also the people who design braking systems for OEMs for a living. Also Road and Track, Car and Driver, the folks who tested the $10,000 Porsche PCCB upgrade, and basically everyone else who understands brakes and physics.


    Then it's really weird you've spent multiple posts trying to insist otherwise...including most of this one I'm replying to now.


    Then again- please provide a source for your claim "bigger brakes" make even the small difference you claim they do- in contradiction of expert after expert saying otherwise.

    Because if not you appear to be posting exactly the sort of claim you just said you like to call out.

    Anyway, back to sourced facts

    Which are that in some cases a big brake kit will make ABS performance WORSE

    Here's stoptech explaining why-
    http://www.stoptech.com/technical-support/technical-white-papers/abs-and-big-brake-kits

    It explains (a bit simplified, though in more detail than your explaination) how ABS works- and why aftermarket brake kits that change the factory pressure-torque (P-T) relationship of the caliper/pad/rotor assembly and the pressure-volume (P-V) characteristic of the system, on which the ABS computer is depending can cause you problems.

    It also explains that the better big brake kits specifically are engineered to offer the as similar as possible P-T and P-V setups as the factory brakes... so that you'll be able to get the same ABS performance as factory brakes, not worse.

    At no point do they suggest the bigger brakes which, again, they are trying to sell you can in any way actually improve ABS performance over the factory ones.

    They can only match them, or for cheaper kits, make them worse.


    If they could improve stopping distance, at all, they'd be highly motivated to tell you.

    They don't because they're an honest brake manufacture. (As is Brembo if you go back and read the bit I posted from them about why they don't provide stopping distance test numbers- because they admit bigger brakes can't stop the car any shorter than factory ones.)
     
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  8. allhands

    allhands Member

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    First of all I want to repeat whar others have said about the Model 3 sound system. It sounds fantastic! Better than any other system I've heard.

    I had always planned on waiting and getting the AWD performance version, but at the current price point I'm strongly considering just getting a Model S. I love my 2015 S85D for the cargo room, hatch, and body style, but I want more range, the facelift, AP2.5 and premium sound.
     
  9. Garlan Garner

    Garlan Garner Banned

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    Good luck.
     
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  10. mhan00

    mhan00 Active Member

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    That’s Tesla’s cost, not the price to the customer. And Tesla, like every other company in the world, needs to charge more for their product than it costs them to make.
     
  11. Knightshade

    Knightshade Well-Known Member

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    Given the only Model 3 they could've torn down at this point is the $49,000 first production one, if its cost was 28k, they would be making a profit on it.

    Likewise, especially as costs drop with higher production, the cost of the 35k model would have to be even lower than the 28k they found for the LR version.
     

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