Tesla really sandbagging performance of AWD

[Swampgator]

A completely new motor sounds like a lot of work. I was making the assumption that it was going to be the existing Model S front motor, it being induction and all.

Tesla went clean sheet for Model 3 design. You can check out any of Jack Rickards EVTV videos to see that. The re-imagined everything, including ditching the induction motor in favor of the switched reluctance PM design. 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. This is the opposite of Model S where the rear motor is used more for acceleration and the front motor for highway cruising.

 

[Daniel in SD]

Tesla went clean sheet for Model 3 design. You can check out any of Jack Rickards EVTV videos to see that. The re-imagined everything, including ditching the induction motor in favor of the switched reluctance PM design. 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. This is the opposite of Model S where the rear motor is used more for acceleration and the front motor for highway cruising.

I sure hope this is not true. I don't want my AWD Model 3 to handle like a FWD car
The only logical way to do it would be for the front motor to be used when the rear motor runs out of power or traction. As far as we know the rear motor is more efficient than the front motor so why would you ever use the front motor if you don't have to?

 

[Big Earl]

I sure hope this is not true. I don't want my AWD Model 3 to handle like a FWD car
The only logical way to do it would be for the front motor to be used when the rear motor runs out of power or traction. As far as we know the rear motor is more efficient than the front motor so why would you ever use the front motor if you don't have to?

During acceleration, the front motor will just be supplemental. The rear motor will still be doing the bulk of the work, retaining the rear power bias.

 

[Brando]

reminder: Tesla, (can we say DNA?) is continuously improvement and NOT just software but the hardware too. Looking at history we see even the induction motors of the S/X have changed and going from RearWheelDrive [how many versions? TeslaTap may have documented] to AllWheelDrive (standard, not optional).

I suspected that perhaps all of the FrontWheelDrive motors would be the same induction motor for economy of scale. This thinking is so last century monopolistic tendencies of corporations (bean counter/Wall St.) mentality. NO. Tesla team constantly improves as fast as is practically possible.

It will be fascinating [to me at least] to read of the motor development of Tesla products. Hope someone documents this progress - but this may well be considered a "trade secret" for now. Same for batteries. ALL other companies are free to do the same - who actually will?
So far the other auto companies are slow on the uptake. couple of talks I suggest for background understanding of batteries:

Yi Cui is an associate professor at Stanford University and SLAC National Accelerator Laboratory

Jeff Dahn currently research is financed by Tesla (since 2016??)
Certainly there are probably even better talks, but you'll have to research on your own. Hope you share what you find. But these talks are still very good basic knowledge of Lithium Ion battery technologies.

Also remember that this continuous improvement is sometime lamented by buyers who fell they bought too soon and missed out on the updated versions. Don't buy till you are ready/prepared and don't buy what you don't want. And for those with the cash flow you can upgrade your ride any time you want - just buy a new one. And for those crazy as me, I'm sure any Tesla good for at least 30 years - if Saab can do it, so can Tesla.

 

[Swampgator]

so why would you ever use the front motor if you don't have to?

Exactly. They will use it mostly during acceleration with gearing to match application.

 

[ZeroRider]

I'm still hoping they are sandbagging the numbers on the performance model.

I'd say it's pretty likely! Purely speculation, but I think Elon gave us a bit of a hint in one of this first tweets about the Model 3 Performance specs: "Cost is $78k. About same as BMW M3, but 15% quicker & with better handling. Will beat anything in its class on the track."

The BMW M3's claimed 0-60 mph time is 3.9s (which has also proven by several auto magazines to be a sand-bagged number). 15% quicker than 3.9s = 3.315s

 

[adaptabl]

In order to increase sales of the performance model, it seems Tesla is really underselling the AWD performance numbers.

LR RWD car has 335 whp, weighs 3838 pounds, and does 0-60 in about 4.7 seconds.
If the AWD induction motor adds 150 pounds and has at least 130 whp, we are looking at a 4 second flat car. They may use software to limit that speed, but they will surely unlock that once they are cash flow positive later this year. Then they will simply proceed to crush the competition. The AWD is a looking to be a really impressive car in it's own right.

I doubt it. They are grading the motors so the P version gets the best quality ones. The regular ones get the poorer quality ones and may not take full power without service issues.

 

[D3xDt3Reaction]

I'd say it's pretty likely! Purely speculation, but I think Elon gave us a bit of a hint in one of this first tweets about the Model 3 Performance specs: "Cost is $78k. About same as BMW M3, but 15% quicker & with better handling. Will beat anything in its class on the track."

The BMW M3's claimed 0-60 mph time is 3.9s (which has also proven by several auto magazines to be a sand-bagged number). 15% quicker than 3.9s = 3.315s

View attachment 314320

And if you add their "Competition Package" (adds 19 hp), then BMW claims 3.8s for the M3. So now we should be 3.23.

 

[Knightshade]

I doubt it. They are grading the motors so the P version gets the best quality ones. The regular ones get the poorer quality ones and may not take full power without service issues.

Or the regular ones and the P ones end up speccing almost identically and all them are "good enough" for the P, and the only real difference is software.

Look at binning for CPUs or video cards- there's been cases where there were real yield issues, but most of the time lower from-the-factory chips can easily be overclocked a fair bit, and safely... so much so Intel had to lock down the ability to do so in their mainline chips because too many people were buying the cheaper ones knowing they ran faster just as well as the expensive chips.

 

[Knightshade]

I'd say it's pretty likely! Purely speculation, but I think Elon gave us a bit of a hint in one of this first tweets about the Model 3 Performance specs: "Cost is $78k. About same as BMW M3, but 15% quicker & with better handling. Will beat anything in its class on the track."

The BMW M3's claimed 0-60 mph time is 3.9s (which has also proven by several auto magazines to be a sand-bagged number). 15% quicker than 3.9s = 3.315s

View attachment 314320

Depends what he means by 15% quicker... 3.9 times 0.15 is .585 so 3.9-.585=3.315

But a mere 3.4 times 1.15 gets you to 3.91. Not much of a sandbag there.

 

[D3xDt3Reaction]

I doubt it. They are grading the motors so the P version gets the best quality ones. The regular ones get the poorer quality ones and may not take full power without service issues.

Seems like there's still a chance...

"Also, not promising anything, but we *might* be able to increase Model 3 Performance power output a little"
- Elon Musk on Twitter

 

[D3xDt3Reaction]

Depends what he means by 15% quicker... 3.9 times 0.15 is .585 so 3.9-.585=3.315

But a mere 3.4 times 1.15 gets you to 3.91. Not much of a sandbag there.

I don't see why we should infer he had a different meaning: percentage change generally implies we start from the first value, a la Percentage Change. In that case (3.315 - 3.9) / 3.9 = -15%, or 15% quicker. 3.9 / 1.15 = 3.39 doesn't seem like valid math if we're talking percentage change, right?

 

[Knightshade]

I don't see why we should infer he had a different meaning: percentage change generally implies we start from the first value, a la Percentage Change. In that case (3.315 - 3.9) / 3.9 = -15%, or 15% quicker. 3.9 / 1.15 = 3.39 doesn't seem like valid math if we're talking percentage change, right?

...no?

15% slower than 3.4 is 3.9... because 3.4 *1.15 is 3.9

so that's only a 0.1 second "sandbag"

or simply a rough approximation since "15% quicker" sounds better than 12.8% quicker (which is the most "quicker" you could use for the official 3.5 of the P3 to still round to the 3.9 official of the M3... 3.5 times 1.128 is 3.948.

 

[D3xDt3Reaction]

...no?

15% slower than 3.4 is 3.9... because 3.4 *1.15 is 3.9

so that's only a 0.1 second "sandbag"

or simply a rough approximation since "15% quicker" sounds better than 12.8% quicker (which is the most "quicker" you could use for the official 3.5 of the P3 to still round to the 3.9 official of the M3... 3.5 times 1.128 is 3.948.

Granted, Elon could have just been using a rough approximation since 3.315 (15% quicker than 3.9) is not 3.5 as advertised. Still, I think (as Elon must have from his other tweet) that the P3 may have more in it than 3.5. No telling what he really meant but fun to speculate.

 

[sreams]

because they are using the front motor to accelerate and the rear motor for cruising at highway speeds. This is the opposite of Model S where the rear motor is used more for acceleration and the front motor for highway cruising.

I sincerely doubt this. When accelerating, the weight of the car shifts to the rear wheels, and they end up having the most traction. It would be a mistake to give the most power to the wheels with the least traction.

 

[Swampgator]

I sincerely doubt this. When accelerating, the weight of the car shifts to the rear wheels, and they end up having the most traction. It would be a mistake to give the most power to the wheels with the least traction.

I never said they would give the most power to the front wheels. Only that the front motor will be geared more for acceleration than highway cruising. This is already known. Yes, the weight shifts to the rear when accelerating. But not all of it does. There is still plenty of opportunity to get extra "pull" from the front wheels. I do think the overall choices made are a little strange, but it makes sense in the context of wanting to simplify production and have the same rear motor across the entire Model 3 lineup. But switched reluctance PM motors do not do torque sleep very well. Induction motors do though. So the front motor pulls during acceleration and then at cruising speed it goes mostly to "sleep" leaving the more efficient rear motor to do most of the work.

 

[Wooloomooloo]

A lot of companies under-state performance figures for the purpose of insurance and other factors. There is a history of this, particularly among Japanese performance cars. Even my lowly Golf GTI - which has official performance figures of 220hp/258TQ - actually has 335hp/270TQ at the wheels (so the crank figures are about 15% higher.

I'm guess the performance Model 3 will have a 0-60 of a little under 3.5 seconds, and the regular AWD under 4.

I suspect the Performance model has a slightly larger battery pack and it's not just software.

 

[Wooloomooloo]

Tesla may or may not uncork both of these at later times but they certainly won't ever let the AWD car approach the performance of the P model. If the original delta in 0-60 times is 1 second flat then I would anticipate that will remain the case after any future improvements.

There will be a new faster P Model soon. When that happens, there is no reason the Model 3 won't be allowed to be as fast as the old P100D... or is that just wishful thinking?

 

[Knightshade]

Granted, Elon could have just been using a rough approximation since 3.315 (15% quicker than 3.9) is not 3.5 as advertised. Still, I think (as Elon must have from his other tweet) that the P3 may have more in it than 3.5. No telling what he really meant but fun to speculate.

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.

A lot of companies under-state performance figures for the purpose of insurance and other factors. There is a history of this, particularly among Japanese performance cars. Even my lowly Golf GTI - which has official performance figures of 220hp/258TQ - actually has 335hp/270TQ at the wheels (so the crank figures are about 15% higher.

I'm guess the performance Model 3 will have a 0-60 of a little under 3.5 seconds, and the regular AWD under 4.

I suspect the Performance model has a slightly larger battery pack and it's not just software.

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.

 

[sreams]

I never said they would give the most power to the front wheels. Only that the front motor will be geared more for acceleration than highway cruising. This is already known.

This is known? Do you have a source?