I think the Model X will be able to claim all of the above. AWD and 4WD. With two motors it could replicate a true 4WD system, or a highly advanced AWD system, or ever a FWD or RWD system. That is why the potential of a dual-motor electric drive gives you.
It is not only capabilities but how it is done. There is no need for a dedicated low range gear since all the torque is available instantly for example. AWD seems the logical way to go plus that is what Elon and everyone connected to Tesla have been saying. There is no point in going exclusive FWD or RWD mode if the next second requires a torque split. It almost certainly will be a highly advanced AWD system.
My apologies, you are correct, he said "only" AWD and two motors in the X! Wow, that will be awesome. I wonder if in the future there will be a similar AWD drivetrain for the S.
I think what some are wanting/suggesting is an "Eco" mode that keeps the front motor in (effectively) neutral (or perhaps regen-only) mode. Or something like that. It wouldn't be something that the car would switch out of while increasing speed. Heck, if I was getting an X that feature might be great if it has a significant impact on energy consumption for longer trips.
My thoughts: I've been thinking they can use a smaller motor up front since there is no need for two motors the size of the current S motor to provide enough power for the X, especially since the pack could not provide full power for two S sized motors. By going with AWD only they can now use two smaller motors, instead of one larger and one smaller, or instead fitting one large motor for a 2wd version and two smaller motors for the AWD version. This makes manufacturing easier and allows a single platform and suspension setup. This smaller motor could also be used alone in the 2wd version of the Gen3, and the AWD version of the Gen3 using two of these motors, if it happens, could be a real screamer and/or the basis of the next gen Roadster.
I'm willing to bet that it will be less efficient. More moving parts = more friction. Maybe there will be some electronic efficiency advantage, but I doubt it. In any case the difference is likely inconsequential. Considering that the vehicle is both larger and heavier, it will get less range than the Model S for the same energy.
Since higher capacity cells already exist, I am willing to bet the X will come as an 85kw and then something higher (100+kw) in order to make up for the loss of aerodynamics that goes with a taller vehicle. I think the Model S refresh will also include the higher capacity cells for increased range at the price of the older versions. This gives better range/performance at the same price, and better margins for Tesla. With current world wide demand, Tesla should not drop the price of the Model S any time soon as that will affect margins directly.
Possible problem, as far as I know the higher capacity cells, 4ah, are volumetrically more dense but not gravimetrically, so that larger pack will add some weight, and hurt efficiency.
JRP3, if you had to guess do you think the net affect of using the higher capacity cells vs the added weight would result in higher or lower range?
Higher range, but obviously with some penalty for the added weight. Long distance driving where range is most important is less affected by weight, the higher aero drag of the X will likely cause more of an issue at highway speeds.
For Tesla Motors to focus only on one version of the Model X likely involves significant costs savings. 1) less engineering, development and testing time and effort. 2) less risk of customer disappointment with different experiences. 3) less complexity in the production line by only have one AWD version. 4) higher volume of single AWD version likely will lead to lower overall production expenses. Two different types of RWD and AWD would have been a much more complex process throughout the system. If someone wants a RWD car, Tesla can just guide that customer to the Model S. I think making the Model X AWD only makes a ton of good sense for Tesla.
+1 (especially the underlined above). I'd be driving a Model S right now otherwise, despite constantly wanting it! Must. Not. Hit. Order. Now. Button.
So if they're going AWD only on the Model X to save money by only having 1 configuration.... Why not go AWD only on both the Model S and X? (I don't remember seeing anyone else theorize this yet).
The Tesla engineer I spoke to at the release event said two motors will be more effecient as power can be directed to each motor as needed, and as the parameters dictate. One motor will be more effecient at low speeds, and the other keeping the car moving at higher speeds. With two motors you can have the best of each.
The problem is you are probably only talking about small differences in efficiency. If one motor is say 93% efficient but two allow an average of 95% efficiency that may not be an actual gain if it doesn't overcome the added weight and rolling resistance.
No, he is referring to starting point. Here's the question: Tesla London Store Opening reception with Elon Musk - YouTube