Dan203
Active Member
I meant from a standing start. They seem to just launch with zero wheel spin no matter how hard you mash the pedal.
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Petition Tesla to make the Model 3 Performance 0-60 <3s
- Thread starter Sutton 3P
- Start date
I meant from a standing start. They seem to just launch with zero wheel spin no matter how hard you mash the pedal.
Swampgator
Active Member
True but it shows the car can spin the tires. It certainly would from a stop if traction control was turned off.No. Anyone who has added stickier tires reported no difference. Lighter wheels do help of course.
I bet we could get to a 3 second 0 to 60 with going light weight for all suspension, wheels etc. and performing some minor surgery on the car interior for weight loss.
Point of information, that's not a burnout.
I'm familiar with burnouts. I used to do 6000 rpm clutch drops in my S2000 all the time
Swampgator
Active Member
It's software that is preventing the wheels from slipping. The car has MORE than enough torque to spin the tires from a standstill.
Knightshade
Well-Known Member
But it's not a software limit due to traction
If it were the car would get faster with stickier tires.
And it doesn't.
Switched reluctance motors traditionally have problems with cogging at low RPMs. I wouldn't be surprised if Tesla programmed in a reduced maximum torque off the line to limit this tendency (though we don't know how prone their PMSR motor is to it, since PMSR isn't exactly the same as classic switched reluctance.)
This still seems very vague and hand waving. Do you have a reference?
If I look at 3 phase inverters, such as: http://www.ti.com/lit/ug/tidudj9/tidudj9.pdf I find that they are rated for a maximum voltage and power output, but I don't see anything in the data sheet about power dissipation being mostly dependent on current, etc. What I do see is equations showing that the main component of dissipated power is proportional to V^2 (see section 2.2.1.10).
Generally, I'm seeing a lot of claims like "yeah, idiot of course it's at the limit already" but pretty much nothing in the way of quantifying that.
Swampgator
Active Member
That is an interesting question I have always had. Given than ANY ICE car that put down 472 lb-ft at 1 rpm would spin it's tires without traction control, why can't the M3P?
right but youre assuming the speakers (and motors/battery) are set to 100% output - if all of your speakers output isnt being fully utilized, you can program the settings to raise in proportion to their current settings based on available output left
you really think that, even not considering Marchs 5% increase, that the p3d battery is 100% tapped for power? And that changes to the acceleration algorithm couldnt improve speed?
you guys gotta free your minds
That isn't a guarantee that it would see tire spin without traction control. If people who get stickier tires don't see improved time, it suggests that TC isn't even being triggered.True but it shows the car can spin the tires. It certainly would from a stop if traction control was turned off.
I'm familiar with burnouts. I used to do 6000 rpm clutch drops in my S2000 all the time
Dan203
Active Member
I wonder if you could do it with really bald tires? At the very least that should trigger the traction control and slow the 0-60 time.
I have no doubt the system has overhead. The question is what impact utilizing that overhead has. I don't know how much room the cell links have, but if they were to heat the battery it should allow for considerably more power output from the pack. Although the cooling architecture might make this rather problematic since the battery isn't on a dedicated circuit with a separate heater. And if the concern is 0-60, the max power only occurs above ~50MPH. So the battery isn't really the major limit anyways. Unless Tesla comes out and says this officially, its all effectively speculation. I'm not sure being confident Tesla is intentionally limiting the car is the most likely option, but it very much is possible.
People tune stock cars and unlock good power all the time. Does this make the manufacture irresponsible, or hyper conservative? It's a very competitive market, I just don't see the incentive to intentionally hold back. I believe its reasonable to assume they have a better understanding of the vehicle than you and I, and they have valid reasons for this beyond product cannibalization. That would mean they could ship wimpier hardware and run it harder to get the same performance at lower cost.
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AlanSubie4Life
Efficiency Obsessed Member
That's not true, if you're talking about torque at the wheels. That's not even close to enough to spin the wheels.
The Model 3 Performance after the 5% bump puts out something like 490 lb-ft of torque, counting front and rear motors together (but not at 1rpm, it's more like at 333rpm, around 3mph - just rough numbers here), but there is a ~9:1 drive ratio, so total to the wheels is at most 4400 lb-ft of torque. There's some loss so the real number is something closer to 4000 lb-ft of torque, which translates to 3700 pounds to the ground due to a 13.2 inch wheel radius - which results in acceleration of less than 0.9g. That's not nearly enough to spin the tires in a straight line on a good surface - even all-season tires can pull a bit over 1g (just look at stopping distances to figure that one out)!
The reason ICE cars with similar torque at the crank can spin wheels is due to gearing...and not surprisingly they can also accelerate faster than a Model 3 Performance - for a time, and with various significant practical caveats.
Swampgator
Active Member
So my old 305 hp Tundra was putting down more wheel torque due to gearing? And my old V6 FWD Camry? I did not know that.
AlanSubie4Life
Efficiency Obsessed Member
Quite likely. You can do the math on those vehicles. Remember that with front wheel drive the front wheels receive all the power at the same time that they are somewhat unweighted, due to weight transfer. So in that case there is less normal force and the tires will slip sooner even with an excellent coefficient of friction (which can exceed 1) - so not necessarily more torque in that case.
Remember than when you change gears the ratio changes and torque is likely reduced (depends on HP curve)! So this condition of more torque (to the wheels) than a Model 3 is often only true in first gear!
I think that’s a pretty obvious no for any normal person.
So is anyone going to give a quantitative answer for what would stop Tesla from increasing the acceleration at low speeds (eg why can’t they make a = 1.2g at 10 mph)? ...and to be clear this is a physics question, not a sales or philosophical question.
Daniel in SD
(supervised)
Some YouTuber needs to put 215/35R18 tires on a P3D. That should increase the torque by 9%! Think of the clicks!
If you could find some 17" wheels that fit the P3D-...
If you could find some 17" wheels that fit the P3D-...
Erleichda
Member
$187k for "more than 1 lap". You realize, with less significantly less range...you are not going to do lap after lap. The range matters too.
A Model 3P has done 33 laps at Laguna Seca. The Model S Raven has that tech.
Let's see what happens next week at the ring...Elon is up to something.
AlanSubie4Life
Efficiency Obsessed Member
The force, man, the force...isn't it?
The clicks would surely pay for the tires.
The guy who shed 450 pounds from his P3D should try it just for kicks.
Daniel in SD
(supervised)
Oops. I flunk basic physics.
It would be equivalent to increasing the torque by 9%.
