Model X performance... is Elon going nuts?

“Even though the X is heavier [than the Model S], it will still go zero to 60 miles an hour in about 4.4 seconds,” Mr. Musk said. “And that’s not even the Performance model.”

With that, and the falcon doors, my guts say that Tesla is targeting an extremely focused (read: small) market. Great vehicle for Tesla to show off, but will it contribute to the bottom line?

I have always defended Tesla's strategy in these forums, and I strongly believe in the "Secret Tesla Master Plan", but with this vehicle I can't help the thought: Are they slowing going off rails...? To me, the Model X doesn't fit the bill of the Secret Tesla Master plan. At least that's my preliminary first impression.

Full disclosure: My perspective is from Germany. I may not fully understand the American passenger car market. But does Tesla?

The Model X spec page shows Performance only on dual motors; Option 2 does not exist.

Sure seems that way right now Brian. If that press release in combination with the summary spec are the final word, 4.4 sec is top of the line, and Elon simply misspoke.

They did leave themselves some wiggle room though. It's curious that you don't see the 4.4 on the spec summary page. Instead it says "when outtfitted with AWD, Model X Performance accelerates from 0 to 60 mph in less than 5 seconds". Lots of numbers are less than 5.

And then in the press release, it doesn't mention AWD together with the Performance spec of 4.4 sec.

Just seems kind of notable that they didn't simply state the same 4.4 number when they described the AWD Performance combo.

It might just be casual and inadvertent, or they might have wanted to craft those slightly different words carefully.

Also interesting how they kept the Model S Performance quiet until late in the game.

Maybe Elon is crazy ...

like a fox.

Mark K | FEBRUARY 18, 2012
"AWD definitely offers better drive dynamics, and would be the cooler choice for the enthusiast.

There is a range penalty to pay if you have the two motors, but only when you flex those muscles."

I agree wholeheartedly with the first sentence, not sure if the second sentence is correct.

With AWD drive there should be regenerative braking with both the front and rear motors/generators.
Rear wheel drive has regenerative braking only in the rear. Front and rear regenerative braking could probably offset the small penalty of having two motors in the AWD.

What if the gains of front/rear regenerative braking more than offset the penalty of two motors? Talk about having your cake and eating it too! To mix metaphors, the Model X will sell like hotcakes!

GoTeslaChicago, you raise a good point. You have a larger range of deceleration rates that could be handled by regenerative braking if you can distbribute the job to all 4 wheels instead of just the rear.

In practice though, this gain is likely to be less than the loss from the harsher demand on the battery when you push it to accelerate quickly.

Taken to extreme, the Roadster can double its range if you to keep it at 25 mph or so, and decelerate gradually.

But a really light foot isn't so fun, so the practical case is where you do acc / dec briskly,, and the other losses kick in.

I'm sure the X would get absurdly high mileage too if you stayed in the perfect zone where these factors are optimal. But how could we pass up the joy of using what it does better than anything else you can buy?

That's why I say you'll take a hit only when you flex those muscles.

It's not that the machine is less good than the 2WD S, AWD clearly is better. it's that you won't be able to resist enjoying its benefits.

Hi Mark,

Of course we're trying to make informed speculation here, but it is still speculation.

Here's my 2 cents worth.

Unlike a gas engine I don't think there is much penalty for accelerating rapidly.
As I understand it, the conversion efficiency of an electric motor is fairly constant over a wide range of rpm. At higher speeds, the energy lost is due to wind resistance, and has nothing to do with how rapidly you achieve the high speed.

Braking is a different story. Even with regenerative braking a lot (more than half?) of the energy used in accelerating is lost. Therefore, stop and go driving where you have to brake a lot will enact a penalty, (lessened by regenerative braking), but it is the stopping that does it, not the rapid acceleration.

Of course I won't be able to resist hitting the accelerator when the light changes, but after a couple of weeks I probably won't do it so much when I know that I'll have to stop at another light only a few blocks away. Acceleration to top speed when entering the freeway will be a thrill, and with no need to stop again, any time soon, my conscience will be clear.

Hi GoTeslaChicago,

You've got the motor efficiency right. Ideally, twice the electric power for half the time results in the same total application of thrust.

The difference is in the battery. The battery impedance (think of this as internal losses), gets worse at higher load.

This is a function of its chemistry and electrode structure. Picture a finite number of tiny holes (electrode receptor sites) for the electrons to exit the cell to get to the motor. If all available paths are full, the rest of the electrons have trouble getting out and some get wasted as heat inside the battery.

The more suddenly you ask high current from the battery, the more prominent this effect. As batteries improve, this effect will be less and will approach more of the ideal you describe. For the event horizon though, this loss is real.

Some months ago, as a sanity check, we did some tests with one of our engineer's Nissan Leaf (also Lithium Ion chemistry like TM). We repeatedly gunned it to 30 mph quickly, but always slowed down gradually to regen efficiently. 30 mph was chosen to dodge aerodynamic drag influences. The battery depletion was significantly worse than if we always accelerated slowly to reach the same speed fot the same total number of miles.

We also use a lot of Lithium Polymer batteries in our work, (similar LiIon chemistry to TM), and you routinely see this. The battery wants to deliver up to a certain rate. Ask for more, and the battery gets hot and dies quicker.

What TM ends up building is speculation, but the physics is not. That's the way these cells work for TM and any competitor (though TM is definitely the best at managing them intelligently).

It's cool to have bigger muscles. Flex them too much, and you get tired.

But then, who could defy?

Model X Performance has such big muscles, and more of them.

And muscles are so cool!

There was a tech article on new LiIon cell architecture from MIT some time ago, which talked about "banding". Essentially, pre-established channels within the battery to route electrons to "exit tunnels" . Claims of faster charge/discharge, absence of heat penalty, etc.

Lets see if I can find it in my Clipmate records ...

They call it a "beltway" design.

With regards to the different comments, perhaps the Model X page is referring to "what they want to advertise for the production vehicle that will be delivered in 2013" vs. "comments about what they've achieved with the specific prototype shown at the press conference"?

Batteries will definitely get a lot better, both in capacity and in lower internal losses at high load. EV demand will fund these advances.

But this will take several years, not months. You can expect your second EV to charge faster and go farther.

But what TM has done now is very brilliant. LiIon cell performance recently reached sufficient critical mass to enable no-compromise EVs, but only if you integrate the cells very cleverly. So TM buys the best cells available and manages them with very smart technology developed in-house. It's indeed the best in the world - which is why Daimler is buying it.

The result is cars (S and X), that make economic sense now. Not years from now. The S is a 5 / 7 series killer right now. Faster, roomier, safer, unmatched grip, more beautiful and not a drop of gas - all at comparable price points. The X will have lower operating cost than a Ford SUV, yet outperform a Porsche Cayenne.

TM uses classic disruptive change strategy:

Whenever you offer a new technology to solve a big problem, don't just outperform on the key feature (no gas), outperform on all fronts. When you eliminate compromise, you make the consumer decision simple, and drive rapid adoption.

From the beginning with the Roadster, to the S, and now the X, in each segment all TM models leverage this strategy.

Once the S is shipping, you'd have to blow off reality to spend another dollar on old technology for a premium sedan.

Do we need 4.4 sec or faster acceleration? No. But buyers compare models on such specs, and if you beat the ICE cars even there, game over.

The largest SUV audience is low-snow city dwellers who currently buy 2WD SUV's. And minivan buyers rarely ever pop for AWD. These kind of guys never go off-road. A 2WD Performance X is lowest cost way to give them high specs (it's half the parts). That's why I think they'll offer it, and why the exact specs vs. config will remain unconfirmed until they are close to production (also smart strategy).

If smart strategy makes Elon nuts ... whatever he's drinking, I'll have one too.

@Mark K wrote: Do we need 4.4 sec or faster acceleration? No. But buyers compare models on such specs, and if you beat the ICE cars even there, game over.

I said in another thread that very fast low speed acceleration of BEV is more a side-effect of used technology than goal to achieve. It doesn't cost you much more to build 300+kW engine and electronics than 100kW. Bigger motors tend to be more efficient than small ones (unlike ICE). Big batteries just plain give huge power.

As long as you use big batteries you pretty much automatically get a very high performance car. Two motors makes that even easier. It's easy for Tesla to make such a car, so it would be just plain stupid not to make it.

And it just keeps getting easier and easier with new technologies. With battery techs like what Brian H above linked even small batteries give enormous power soon, and electronics get better and better all of time.

Well, I see no indication there will be a RWD Perfomance X. I think it's an unnecessary complication. If you want RWD Performance, you'll be "stuck" with an S, I think.

It doesn't cost TM any more engineering to offer the 2WD Performance flavor if they choose to do it. They're already doing a 2WD version, and already have the performance motor and electronics in the parts bin. It's simply a business decision if the demand is there.

Personally, I'm sticking with the S Performance for me, but I'm thinking my wife will discover her new AWD Performance X surprise in the driveway in 2014. It's the safest and most sure-footed family protectobile. And I would steal the wheel from her for weekend trips.

If they offered AWD on the S, I'd go for it across the board on all my EVs. It's just technically better.

Just quickly, before this thread turns into an RWD vs. AWD discussion -- there's a very spirited discussion around these issues already going on here:

Here is a video of getting up the driveway at my other home in the Rockies, called Hole in the Wall. The last pitch before the house and after the turn is a 15% grade. All I want is an electric vehicle that can make it up this most of the time in the winter. Even my jeep with air lockers and good snow tires can't make it up after a 2 foot, 60 cm snowfall until its plowed. This video was done in a 4WD Chevy pickup in low range with the transfer case locked.

Butch, I left a comment in the RWD thread:

It would be really interesting to try that 15% incline with an RWD Model S or Roadster. Let us know what you learn! ;-)

In that other thread there are also links to videos that show the Roadster perform on snow and ice, some of them showing quite impressive performance stopping half way up a snowy hill and then getting going again.

FWIW, at the Boston beta event I was told that Tesla had hired a third-party assessment of the Model S performance in snow. They are clearly expecting to publish impressive results.

Beautiful post. What is wrong with Tesla? Why do they keep targeting other cars? Faster than this, bigger than that... In the end its about price and value. I agree the "go electric" crowd will buy to keep them alive but we live in a real world. The X is just a statement and it does not save the owner any money even though electric is cheaper. Its going to be too expensive. It has a large touch screen, falcon wing doors, and side cameras instead of mirrors. Why add these "new" to automoblies features in one vehicle. I think they are trying too hard to impress people and not being realistic. Get me a full size car with great range and at a good price. Why prolong the Gen III with the X? I hope they are still around to produce a Gen III.

What's with all the irrational posts? TM is obviously not targeting your and your priorities. 'Bye.

Because its easy to modify the Model S skateboard to build the Model X.

Building a new skateboard thats cheaper than the Model S for Gen III? That's a little bit more work.

SMahindra21 >>> "...Why prolong the Gen III with the X?"

One word: Foreplay

I love Tesla's approach on the Roadster, S, X, Gen III.

If they survive -- highly likely, now --- they will literally rule the world.

There are likely to be a few "variants" on the S platform, too: the cabriolet, pickup, van, etc. Maybe announced soon, per Elon.

The beauty of the robotized line is that all can be produced together on it.

SMahindra21 >>> "...Why prolong the Gen III with the X?"

I think a major under appreciated factor affecting the timing of the Gen III is the battery cost. If the Gen III were completely designed and ready for production now it would flop. Why? Because the cost of the battery is currently too high to make an affordable AND desirable electric car. We need 3-4 more years of 8% per annum battery improvement/cost decline to make the Gen III possible.

Therefore the extra volume & profits of the Model X will help make the Gen III both possible and successful.

More profits equals more money available for Gen III R & D.

More volume (Model X combined with Model S) equals economies of scale necessary to drive battery & battery pack production costs down.

@ GoTeslaChicago
I agree with you on this. Because the most important (and decisive) part of an EV is the battery pack, which has to be able to store enough electricity to make a more than reasonable range possible, and which does not cost too much. Therefore, in order to be successful, it would be wise not to introduce the "Tesla GEN III car" too soon. Be patient and focus on the production of Model S, Model X, and other variants (i.e. station wagon, coupe, cabriolet) on this platform/skateboard.

IMHO Too much emphasis is being placed on performance 0 to 60 times etc. When reading in these forums and elsewhere the buying public seems to be much more focused on RANGE! including myself.

If the performance is comparable to other ICE vehicles in the Model X class of close competitors, range becomes king.

If I want 0-60 I could drive a top fuel dragster Blows the doors off anything on the road 0-60 but it only has less than a half mile range, which is not very useful.

For my $$ I'd rather pay a premium for RANGE!! Best in class range is WAY more useful to a BEV driver than face stretching performance.

Power is side-effect of having big battery, so you get both without any penalty to either.

@ Timo

Yes, because EV's automatically have instant torque, which is a great advantage.

Power being instantaneous has nothing to do with this.

Let me explain:

lets say you can drain one battery in half a hour giving it 2C rate.

Two batteries in parallel you can drain twice as much current without dropping voltage and without draining individual battery any faster than 2C, so you just doubled your power without causing any additional strain on batteries. It still takes half a hour to drain the battery, but you get twice the output.

Which means: Double the energy capacity = double the power capacity.

This leads to big battery = a lot of power pretty much automatically. People talk about power density just because of this relation.

Many anodes make light work.

I have to add here that "big" in this case means physically big. When battery chemistries change you might get upgrade to energy density without upgrade to power density which can cause problems if the battery size (physical) gets downgraded to keep capacity same.

This is problem with Li-Air -batteries, they don't have very high power densities, which means you need physically big battery to get power to move the car and get charge fast enough that you don't die to old age before you have charged enough to drive one day. Consequently you have battery that could go coast to coast (US) in one charge (and then take month to charge it back to full).

OTOH for traditional Li-Ion -batteries some lab results give absolutely insane C-rates, biggest I have seen was something in order of 10000C (meaning you can drain battery in about 1/3 of a second).

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