Why does the S85D have greater listed range than the P85D?

[Bighorn]

I'm simply challenging out that the assertion of what they ARE doing being made in some posts based on what the ordering page says.

Tesla has chosen to quote what power the motor would deliver, not what it's capable of, therefore using that as an authoritative source of what the motor size must be is questionable.

We have at least two instances of a component being specifically upgraded solely based on matching the car configuration: inverter (for the P models), and 60 & 85kWh battery packs.

We also have several instances of Tesla including hardware on the car capable of more, but limited based on the configuration: 40kWh packs, supercharging hardware, motor (in the non-P), autopilot sensor package.


Obviously time will tell, but until then it's speculation, and thus stating authoritatively one way or the other is difficult.

Sorry, I was using an idiom with a person whom I know that posed the question. I assumed you were being contrarian to make a point, but you must admit that the economic and weight costs of leaving a big motor in the rear would not sit well with any engineer or stockholder. I appreciate the validity of your argument, but I'm guessing you wouldn't be willing to make any wagers

 

[scaesare]

I appreciate the validity of your argument, but I'm guessing you wouldn't be willing to make any wagers

Nah, I have no vested interest one way or the other.

I've just simply seen thing asserted on the forum many times based on non-authoritative data (hand would Perf motors, anyone?), that I strive to be careful and add/ask for clarity when I see questionable statements go by...

 

[Bighorn]

Nah, I have no vested interest one way or the other.

I've just simply seen thing asserted on the forum many times based on non-authoritative data (hand would Perf motors, anyone?), that I strive to be careful and add/ask for clarity when I see questionable statements go by...

I'll happily recant, but for now I'm going with it

 

[brkaus]

The S85D also has higher top end speed. Perhaps different gearing in one of the transmissions? Not sure if there is a specific rpm that would be more efficient with an electric motor?

 

[jerry33]

The S85D also has higher top end speed. Perhaps different gearing in one of the transmissions? Not sure if there is a specific rpm that would be more efficient with an electric motor?

The difference in the amount of heat produced by the inverters because of the different gearing is the most convincing argument right now.

 

[Bighorn]

The S85D also has higher top end speed. Perhaps different gearing in one of the transmissions? Not sure if there is a specific rpm that would be more efficient with an electric motor?

I think that's a fairly good assumption. It will be interesting to see what the gear ratios to the two motors are ie will the rear motor get a different gear ratio or will the smaller front motor have more of an overdrive gear? Peak torque starts to drop off at a certain RPM far shy of peak RPMs (I forget--8 or 9K perhaps), so a second gear has always been desirable. Doing that with two separate single geared motors rather than having a transmission required to shift simplifies the process and protects the gear box.

 

[NoMoDinos]

The difference in the amount of heat produced by the inverters because of the different gearing is the most convincing argument right now.

It will be interesting to see what the mileage is like at varying speeds. I'm planning on plotting my energy usage per mile at a few different speeds on the same flat stretch of road and compare with a friend's P85.

(BTW, in four posts you'll hit the big jackpot!)

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I think that's a fairly good assumption. It will be interesting to see what the gear ratios to the two motors are ie will the rear motor get a different gear ratio or will the smaller front motor have more of an overdrive gear? Peak torque starts to drop off at a certain RPM far shy of peak RPMs (I forget--8 or 9K perhaps), so a second gear has always been desirable. Doing that with two separate single geared motors rather than having a transmission required to shift simplifies the process and protects the gear box.

You've got a whole lotta mechanical knowledge for an opthal-malologist type of feller, Big

 

[Olle]

Nah, I have no vested interest one way or the other.

I've just simply seen thing asserted on the forum many times based on non-authoritative data (hand would Perf motors, anyone?), that I strive to be careful and add/ask for clarity when I see questionable statements go by...

It is very obvious that the 85D has small Drive Units front and rear. Some indications:
1. weight. the old rear DU weighs 150 kg and the new DU weighs 115. Ill let you add them up and then look at the weights of 85D and P85D.
2. pictures. The order page has pictures of the DUs both for the 85D and the P85D. You can clearly see how the 85D has the small DU front and rear and the P85D has the big old DU rear

Need more evidence?

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I've already confirmed my order, but was just wondering. I had assumed it would be a situation like the 85 vs P85, where both are capable of the same range given the same driving style. Any ideas?

@OP: I think all the explanations people have posted are good reasons for the difference in range. I would just add that 85D probably has a combination of gear ratios, front and rear, optimized for range while the P85D probably has ratios optimized slightly more toward acceleration.

 

[Kandiru]

No, they have the same motor: the P85's control electronics are just able to provide more juice to it than the S85's do. When driven the same, they consume the same amount of battery power.

Which of course begs questions about motor longevity, especially that knowing myself (Audi S4 owner) there will be some Kalifornicators and others who will rape it at the track.

S85D future owner here also. Makes a lot more sense, I will only be sacrificing 0.1s on the 0-60 from my old car, but oh boy how I will miss the 6MT, or maibe not, to be compensated by uniform delivery of torque.

 

[henderrj]

It seems to me that Elon claimed the new motors were more efficient because they are newer technology. I think he said something like "2nd generation". There's also a video on the Tesla site titled "high efficiency electric drive unit" (added last November) showing off new equipment for making said units. Related?

 

[Matias]

I asked if there is any difference between front and rear motor. Tesla's worker said, that the front and the rear motor are geared differentially. But of course that worker might be wrong.

 

[ScepticMatt]

Because the new motors are more efficient (a variant of which will be used in the Model 3)
Weight is probably a pretty minor difference at high-ish speeds.