Tesla really sandbagging performance of AWD

[JeffK]

Pretty sure Tesla has said larger pack won't physically fit in the car.

Well, Elon said 100 kWh won't fit with current battery tech.

No, will be lower. Wheelbase can't fit 100.
Elon Musk on Twitter

There were rumors out of Germany that there was a future 90 kWh version.
Das Model 3 ist Teslas neues Glanzstück
another out of the UK
Tesla Model 3 review: almost a Volks-Tesla

 

[D3xDt3Reaction]

I suspect 2 things will happen-


1) Folks will test these cars with 1' rollout, not realizing the official spec doesn't do that, get times that are a couple tenths quicker, and insist it's evidence Tesla is "sandbagging" with the official spec. This already happened with the first production 3, and will happen again with AWD and P.

2) There will indeed be at least a few tenths officially improved someplace down the line with an OTA update, as has happened to the S in the past, when competition requires it.






Pretty sure Tesla has said larger pack won't physically fit in the car.

And math-wise there seems no need for it to be larger... the S75D, a non-P discharge rate model, is 4.2 0-60 and 1000 lbs heaver than the P3D....(and the P85D Ludicrous does 2.8 in the same much heavier car...)... so 3.5 (or even lower) seems entirely reasonable on a P with the pack in the LR model 3 (which seems to be nearer 80 than 75 anyway)- no to mention it'd overly complicate production using a different battery pack.

Agreed. Incidentally does Tesla quote times without rollout for everything these days? At some point I am fairly sure they were using rollout.

 

[Knightshade]

Agreed. Incidentally does Tesla quote times without rollout for everything these days? At some point I am fairly sure they were using rollout.

That Motor Trend 1 foot rollout

This post shows Tesla saying they used it for P models but not regular models (and only after not initially disclosing that)

Dunno if they officially say what they do with the 3 anywhere- but the fact rollout usually knocks 0.2-0.3 off the "regular" time, and car mags were getting ~0.3 quicker 0-60 on the first production Model 3 using rollout pretty strongly suggests Teslas 5.1 spec is without it.

It'd be interesting if they still only use it for the P, because that'd suggest the performance difference from the AWD 3 to the AWD P3 is even smaller than the numbers appear.

 

[D3xDt3Reaction]

That Motor Trend 1 foot rollout

This post shows Tesla saying they used it for P models but not regular models (and only after not initially disclosing that)

Dunno if they officially say what they do with the 3 anywhere- but the fact rollout usually knocks 0.2-0.3 off the "regular" time, and car mags were getting ~0.3 quicker 0-60 on the first production Model 3 using rollout pretty strongly suggests Teslas 5.1 spec is without it.

It'd be interesting if they still only use it for the P, because that'd suggest the performance difference from the AWD 3 to the AWD P3 is even smaller than the numbers appear.

That’s what I remembered reading too - Tesla using rollout for P models. Certainly BMW is using it for their M3 given that Motor Trend’s 3.8 figure matches theirs exactly: 2017 BMW M3 With M Performance Parts First Test Review: Dial M for Modification - Motor Trend. I think Tesla ought to either use rollout everywhere or not use it anywhere - hard to compare apples to apples otherwise.

 

[Wooloomooloo]

Pretty sure Tesla has said larger pack won't physically fit in the car.

And math-wise there seems no need for it to be larger... the S75D, a non-P discharge rate model, is 4.2 0-60 and 1000 lbs heaver than the P3D....(and the P85D Ludicrous does 2.8 in the same much heavier car...)... so 3.5 (or even lower) seems entirely reasonable on a P with the pack in the LR model 3 (which seems to be nearer 80 than 75 anyway)- no to mention it'd overly complicate production using a different battery pack.

Yeah fair enough, thinking about it a larger pack makes no sense. It may be that there are slightly more durable components between the pack and the motors to allow for more power delivery over longer periods of time. Musk’s tweets about it out performing the M3 on a track (or anything in that class) suggests components more suited to such driving.

 

[PhaseWhite]

I suspect 2 things will happen-

...
And math-wise there seems no need for it to be larger... the S75D, a non-P discharge rate model, is 4.2 0-60 and 1000 lbs heaver than the P3D....(and the P85D Ludicrous does 2.8 in the same much heavier car...)... so 3.5 (or even lower) seems entirely reasonable on a P with the pack in the LR model 3 (which seems to be nearer 80 than 75 anyway)- no to mention it'd overly complicate production using a different battery pack.

Given the lack of the large high torque rear motor that the P85DL had, I don't think we'll get down to the same 0-60 levels. That said, overall horsepower might be pretty close so at highway speeds a P3D might be as fast or faster than a P85DL.

Supposedly the Model 3 BMS at one point had a limit of 370KW discharge limit.
Tesla Model 3 gets hacked, reveals more details and great potential for dual motor/ performance versions

Though it wouldn't surprise me if the limits get a bump for the P3D firmware once Tesla has more data from cars in the field. The Model S P100D for instance can discharge at around 550KW. 98KWh usable battery compared to ~ 76KWh would imply the P3D battery could do ~425KW.

I think there will be an extra performance toggle added at some point to P3D which will hit around ~3.2s 0-60.

 

[ℬête Noire]

The Model S P100D for instance can discharge at around 550KW. 98KWh usable battery compared to ~ 76KWh would imply the P3D battery could do ~425KW.

Doing the math that way is only good for a very rough approximation. Because the batteries are built with substantially different cells and battery construction, you can't really assume direct correlation like that.

The article you link implies a potential upper limit of 1.2kA * 402V = 482.4kW from the battery. Which would be nutso if it could get all that to the wheels since the P3 is going to be around 1850kg compared to about 2,240kg for the P100D. So it'll only need to do about 83% as much total work to get it to a given velocity. I've seen estimates of the P100D putting about 590HP-600HP on the ground, so the P3 would only need to put about 490HP on the ground.

If the P3 is able to channel all of that 1200A at 400V, even with a conservative 85% drivetrain loss from battery to wheels, that's still roughly 550HP to the wheels. The question then is only what tires you'll need to actual put that on the ground rather than traction control throttling to keep the wheels from burning up.

 

[ecarfan]

They will have worked very hard to minimize the weight of the front induction motor, and the reduction gear will be different ratio most likely as well, because they are using the front motor to accelerate and the rear motor for cruising at highway speeds

Please site a credible source to support your statement. I’m interested...

 

[ℬête Noire]

Please site a credible source to support your statement. I’m interested...

Here's an old discussion about lower gearing on front motor of the Model S D, over on the TMC Model S forum.

motor efficiency It seems somewhat inconclusive there about the gearing, I've been trying find a better confirmation. Coming up short so far.

It's fairly reasonable to assume they'll do the same thing on the Model 3 with whatever they've done on the Model S, especially since induction motors tend to be better at "torque sleep"** compared to PM motors like the Model 3 has in the rear.

** A fancy way to say "coasting", drawing no electricity nor inhibiting the vehicle's forward momentum.

 

[Knightshade]

Here's an old discussion about lower gearing on front motor of the Model S D, over on the TMC Model S forum.

motor efficiency It seems somewhat inconclusive there about the gearing, I've been trying find a better confirmation. Coming up short so far.

Undocumented | TeslaTap

FWIW that lists the large motor in the S/X at 9.73:1, the small motor at 9.34:1

The model 3 rear drive unit is listed a slew of places as 9.0:1- and obviously nobody knows yet on the front motor