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Tesla ‘Easter Egg’ Makes the Fast-Accelerating Model S Even Faster

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Re: Tesla ‘Easter Egg’ Makes the Fast-Accelerating Model S Even Faster

#41

Post by cjrp »

ska wrote: post #24
tankenmate wrote: post #16

Earlier quoted context omitted.

But downforce isn't appreciable until over 50mph (80kph), short of having stupidly oversized wings (which would drastically slow your acceleration) or active downforce (fans etc).

This is actually why a lot of expensive sports cars have 0-60 times of 2.9 seconds. Unless you design specifically for it, it's difficult to generate much downforce at low speeds. Related: if you've ever wondered why some drag cars (e.g. Funny cars) have short exhaust pipes angled up and back, now you know.

Similar to the Red Bull F1 car's exhaust-blown diffuser: http://jalopnik.com/5892403/the-exhaust-pipe-that-made-red-b...

Re: Tesla ‘Easter Egg’ Makes the Fast-Accelerating Model S Even Faster

#42

Post by jackmott »

LeifCarrotson wrote: post #39
jackmott wrote: post #28

Earlier quoted context omitted.

Cars can do more than 1G even without downforce. Sports car street tires commonly ~1.2g, race tires commonly ~1.5g+ High school friction is wrong. Source: various of my cars (in the past, I just have lame hybrids now) and a g meter

> High school friction is wrong. No, it's at least mostly correct. High school friction says F = mu * W Where F is the output force, mu is the coefficient of friction, and W is the normal force (typically equal to the weight). If it's failed you, it's failed in failing to mention that the tire-road interface can have a coefficient of friction greater than one, and in failing to mention that the normal force can be in…

High school physics tends to claim that the coefficient can't be greater than one.

Source: note all the people here who thought it couldn't be greater than one.

Re: Tesla ‘Easter Egg’ Makes the Fast-Accelerating Model S Even Faster

#43

Post by CarVac »

gravypod wrote: post #40
jaredraby wrote: post #38

Earlier quoted context omitted.

It's not equal torque at all rpm.

Effectively it's more equal then an ICE. Also if you can get someone who has a lot of experience with motor control they can get you going pretty quickly. I'm assuming what's in the Tesla is a brush-less DC motor and there are a few things you can do (especially since you're on some serious batteries in the Tesla) to push some serious torque at the startup curve. You're probably only running a modulated power start f…

Teslas have AC induction motors.

Re: Tesla ‘Easter Egg’ Makes the Fast-Accelerating Model S Even Faster

#44

Post by aecing »

d0mine wrote: post #13
Desustorm wrote: post #2

Not sure I agree with the terminology of the article (fast rather than quickest accelerating), but I thought this quote was special: > Speeds like this offer more Gs than Earth, so the rate of acceleration is faster than falling. It can feel difficult to support your head and shoulders if you don’t lean back on the headrest.

1 g is nothing. "A hard slap on the face may impose hundreds of g-s locally" "Early experiments showed that untrained humans were able to tolerate 17 g eyeballs-in (compared to 12 g eyeballs-out) for several minutes without loss of consciousness or apparent long-term harm" https://en.m.wikipedia.org/wiki/High-G_training

from the paper(o) in citation 3 from the linked wiki article(i):

> The terms "eyeballs in" "eyeballs out," and "eyeballs down" correspond to acceleration fields AX, -Ax, and AN, respectively, where AX, -Ax, and AN refer to the direction of acceleration forces measured in the conventional airplane body-axis coordinate system.

> AN acceleration factor, ratio of acceleration force to weight, positive when directed upward along spinal axis (i.e., from seat to head )

> AX acceleration factor, ratio of acceleration force to weight_ positive when directed forward transverse to spinal axis (i.e., from back to chest)

(o) https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/199802...

(i) https://en.m.wikipedia.org/wiki/High-G_training

Re: Tesla ‘Easter Egg’ Makes the Fast-Accelerating Model S Even Faster

#45

Post by WordyMcWordface »

It also depends on how you define "Worlds fastest car" While there is no doubt this is a fast car and that time is a stonking 0-60 time. I am lead to believe it can't complete a full flat out lap of the Nurburgring as constant high speed/full throttle use heats up the battery to the point where performance has to be limited.

So while it will be great to "hoon about" in and should be a win at the traffic light gran prix there are probably much better track day cars.

Re: Tesla ‘Easter Egg’ Makes the Fast-Accelerating Model S Even Faster

#46

Post by semi-extrinsic »

josefresco wrote: post #30
cynix wrote: post #20

Earlier quoted context omitted.

> I want range, range, and more range. I could not give a damn about how fast I get to the next stop light or supercharger. You're not the target audience for their top-of-the-line P100D. It's aimed at people who would otherwise buy Bugatti Veyrons, Ferraris, etc., and range probably doesn't even come up in their decision making process. The Veyron has a range of 50 miles at top speed, for example.

"aimed at people who would otherwise buy Bugatti Veyrons, Ferraris" More like Porsche 911 Turbo, Mercedes SLS, Audi R8 buyers.

No, I think more like Dodge Charger Hellcat buyers. Those who pony up for a 911, SLS or R8 want a car that'll go faster around the Nürburgring than a Honda Civic Type R. Which I think even the P100D won't be able to (too heavy, brakes and motors overheat).

Edit: why the downvotes? It's well documented that the P90D is no quicker than a Civic Type R around a proper racetrack.

Re: Tesla ‘Easter Egg’ Makes the Fast-Accelerating Model S Even Faster

#47

Post by jameshart »

mirimir wrote: post #31
return0 wrote: post #21

Earlier quoted context omitted.

and 4/4ths of a car

With rear-wheel drive, acceleration transfers most of the vehicle weight to the rear wheels. That's why funny cars do wheelies. That doesn't work so well for front-wheel drive, so those vehicles can't accelerate as quickly as rear-wheel drive vehicles. With four-wheel drive, weight transfer cuts both ways, but more rubber on the road helps, for sure. Low center of gravity helps too, I think.

With wheels on the bottom of the car acceleration transfers weight to the rear axle. The forward forces on the car body are below the CG so produce a net rearward tilting torque.

Re: Tesla ‘Easter Egg’ Makes the Fast-Accelerating Model S Even Faster

#48

Post by gravypod »

CarVac wrote: post #43
gravypod wrote: post #40

Earlier quoted context omitted.

Effectively it's more equal then an ICE. Also if you can get someone who has a lot of experience with motor control they can get you going pretty quickly. I'm assuming what's in the Tesla is a brush-less DC motor and there are a few things you can do (especially since you're on some serious batteries in the Tesla) to push some serious torque at the startup curve. You're probably only running a modulated power start f…

Teslas have AC induction motors.

If they do that then they can also take advantage of mutli-phase power that they could modulate to change the speed thereby running it at a higher torque at lower speeds.

Re: Tesla ‘Easter Egg’ Makes the Fast-Accelerating Model S Even Faster

#50

Post by Viper007Bond »

WordyMcWordface wrote: post #45

It also depends on how you define "Worlds fastest car" While there is no doubt this is a fast car and that time is a stonking 0-60 time. I am lead to believe it can't complete a full flat out lap of the Nurburgring as constant high speed/full throttle use heats up the battery to the point where performance has to be limited. So while it will be great to "hoon about" in and should be a win at the traffic light gran pr…

Acceleration is also relatively poor above about 100 MPH. It's an amazing beast, but yes certainly a traffic light car no sports car.
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