Sport vs. Non-Sport the same motor?

[Doug_G]

At 215kW and 800A, the voltage is only 269V. That's quite a drop from nominal pack voltage; does this actually happen?

 

[TEG]

I have heard the phrase "Sport PEM" around the store...

Doesn't say much, but the PEM in the Sport seems to have its' own badge...

Also, I saw pictures of the barcode sticker on the side of the PEM where there was handwritten "Base" or "Sport" depending.


By the way, the 2.0 motors seem to have a B (for "Base") or S (for "Sport") hand written on the side.

All of this suggests that there is something different in both the motor and PEM between Base and Sport.

When they transferred motor production from Taiwan to Palo Alto, I don't know if it changed anything.
I suppose one possibility is that they could only make Sport motors now, but that is just idle speculation.

 

[Young]

There is another possibility:
I do not know how good the winding machines are, and how tight they wind the wire. Tesla did not say one motor has more windings, but did say it has less resistance.
Maybe manual winding uses shorter wire to achieve same number of windings.

I haven't seen the 2010 manual yet. Has Tesla actually stated how many more windings they're able to achieve in the Sport motor?

Quick freshman physics explanation:

To first order, you can think about it in terms of the basic solenoid equation

B=mu*n*I
​

Where B is the magnetic field, mu is a permeability constant, n is the number of windings per unit length, and I is the current.

So you can see if you're able to increase the number of windings, n, by say 5%, you get a 5% higher magnetic field, B, for the same current, I. In a motor that higher magnetic field means more torque, again for the same current (to first order).
​

 

[zack]

At 215kW and 800A, the voltage is only 269V. That's quite a drop from nominal pack voltage; does this actually happen?

DC is different from AC. RMS voltage is used in equations... 269 * 1.414 = 380 peak-to-peak. If you measure AC from the tip of the upper wave to the bottom of the trough, that's called peak-to-peak voltage. That voltage has to be divided by the square root of 2 (about 1.414) to calculate RMS voltage (root mean square) which is the equivalent DC voltage.

 

[Doug_G]

DC is different from AC. RMS voltage is used in equations... 269 * 1.414 = 380 peak-to-peak. If you measure AC from the tip of the upper wave to the bottom of the trough, that's called peak-to-peak voltage. That voltage has to be divided by the square root of 2 (about 1.414) to calculate RMS voltage (root mean square) which is the equivalent DC voltage.

Actually, conversion from RMS to peak-to-peak is 2.828. You only did RMS-to-peak. Besides they probably calculate using the input power.

 

[zack]

Thanks for that correction.

 

[bolosky]

At 215kW and 800A, the voltage is only 269V. That's quite a drop from nominal pack voltage; does this actually happen?

This is the output current of the PEM, not the input. At low RPM, the motor wants relatively low voltage/high current, and the sport PEM can deliver that better than the standard one. In fact, power draw is less than 215kW until about 40MPH, so the output voltage is even lower than you say.

This analysis is backed up by the fact that the difference between the sport and non-sport is below 40MPH; above they're pretty much the same (because they're limited by the ESS power output, and there's no difference in ESS between the models).

 

[Doug_G]

This is the output current of the PEM, not the input. At low RPM, the motor wants relatively low voltage/high current, and the sport PEM can deliver that better than the standard one. In fact, power draw is less than 215kW until about 40MPH, so the output voltage is even lower than you say.

Okay that makes sense; this is a chopper drive after all.

So what is the difference between the PEMs? More IGBTs to provide less resistance? Better heat sinking? Or are they simply adjusting the timing and detuning otherwise identical hardware?

 

[smorgasbord]

Having just bought a 2.5 non-sport, I might be able to add/clarify some information here.

First, the 2.5 Addendum repeats specs that were quoted here earlier:
Motor:
Maximum net power:
Roadster: 215kW (288HP) @ 5000-6000 rpm
Roadster Sport: 215kW (288HP) @ 4400-6000 rpm

Maximum torque:
Roadster: 370 Nm (273 lbf.ft) @ 0-5400 rpm
Roadster Sport: 400 Nm (295 lbf.ft) @ 0-5100 rpm


So, I gather the real difference is that below, say, 55MPH you get an additional 22 lbf.ft of torque and a power curve that peaks 5MPH sooner. That's where the 0.2s improvement comes from.


Some pieces of the $19,500 Sport package are available separately:
Adjustable Suspension: $4000
Forged Wheels: $2900
Tires: Yokohama A048 vs AD07 $850
Which leaves $11,450 for the motor/PEM part of the upgrade (that $520 for each pound-foot of torque!).

Of these, only the adjustable suspension was worth the money to me. Thunder Gray looks great with the stock cast wheels, IMHO. I'm not driving hard enough to warrant the extra sticky tires. At least, not yet. ;^)


BTW, custom ordering is fading fast. As of last month all custom orders had to be Sport models and Rally seats were no longer available.

 

[TEG]

So, I gather the real difference is that below, say, 55MPH you get an additional 22 lbf.ft of torque and a power curve that peaks 5MPH sooner. That's where the 0.2s improvement comes from.

Yes, I think about sums it up. The sport has a little extra kick in the lower speed range, then accelerates similarly to non-sports as you get past the (US) speed limit.
Tracks tests showed the Sport still had that same ~0.2s advantage all the way through the 1/4 mile up to top speed.

 

[user497]

The sport has a little extra kick in the lower speed range, then accelerates similarly to non-sports as you get past the (US) speed limit.
Tracks tests showed the Sport still had that same ~0.2s advantage all the way through the 1/4 mile up to top speed.

I think the question remains however: is the extra torque really due to a difference with the motor or is it just a firmware change?

 

[TEG]

My guess would be both. Another question would be: is it just a firmware change in the PEM, or different hardware too?

 

[smorgasbord]

Yes, I think about sums it up. The sport has a little extra kick in the lower speed range, then accelerates similarly to non-sports as you get past the (US) speed limit.
Tracks tests showed the Sport still had that same ~0.2s advantage all the way through the 1/4 mile up to top speed.

OK, so a related question is what's the difference on 0-60 times between Standard and Performance modes, for Sport and non-Sport? I'm assuming the HP/Torque specs are for Performance mode. What's different in Standard mode? Is a non-Sport in Performance mode still slower than a Sport in Standard mode, for instance?

 

[tdevince]

Doesn't say much, but the PEM in the Sport seems to have its' own badge...

Also, I saw pictures of the barcode sticker on the side of the PEM where there was handwritten "Base" or "Sport" depending.


By the way, the 2.0 motors seem to have a B (for "Base") or S (for "Sport") hand written on the side.

All of this suggests that there is something different in both the motor and PEM between Base and Sport.

When they transferred motor production from Taiwan to Palo Alto, I don't know if it changed anything.
I suppose one possibility is that they could only make Sport motors now, but that is just idle speculation.

PEMs are identical. When my PEM failed (non-sport), the tech replaced it with a Reman PEM that has the Roadster Sport badge. In fact, he made a note to replace the badge with a non-sport during my annual maintenance. He told me the PEMs are identical, however, the firmware setup is different depending which model the PEM is installed.

 

[Doug_G]

OK, so a related question is what's the difference on 0-60 times between Standard and Performance modes, for Sport and non-Sport? I'm assuming the HP/Torque specs are for Performance mode. What's different in Standard mode? Is a non-Sport in Performance mode still slower than a Sport in Standard mode, for instance?

It's on the order of 0.2 seconds, for a non-Sport at least.

 

[S-2000 Roadster]

I'm not sure there is actually any difference in the motor. The same Tesla person that said the motor is the same also said that Tesla may someday offer firmware "performance upgrades" for a price to current customers. When I questioned the ethics of such a practice, they said that there are many companies that offer after market chip upgrades for ICE cars to get better performance. Although this is true, I don't think there are any car manufactures that purposely sell "performance hindered" cars just so they can sell them an upgrade later. This practice is far more common in the electronics and software world where manufactures sell products and later sell "unlock" codes to enable features that were there out of the box but disabled until purchased. I don't fault Tesla for such a practice, it is just new for the automotive world.

The ethical dilemma that you pose assumes that Tesla has already figured out every possible firmware upgrade, has the firmware images ready to go, and is merely holding back so they have the option of selling upgrades in the future. That makes absolutely no sense, because why wouldn't they be offering those upgrades already so they can collect the cash now?

I do not see an ethical problem with what Tesla is doing because they provide the best firmware that they have at the moment. The mere fact that they might someday discover a way to get more out of the same hardware, and could make this improvement available via firmware upgrade, does not mean they are violating any sort of ethical rule.

As a firmware developer, I can assure you that it is very difficult to determine the best possible algorithms in a finite time frame. Tesla is not holding back, but they're just pointing out that anything they discover in the future can be made available, provided your hardware is capable.

But the catch is the limits of the hardware. With even minor internal differences in the motor, or circuit differences in the PEM, the firmware is still limited to each combination of available parts. So, while they might be able to increase the non-Sport performance, that doesn't mean they can simply provide performance that is identical to the Sport (besides, they would likely make the same improvements to the Sport firmware, thus leaving the non-Sport behind by the same relative amount).

In contrast, the electronics industry practice that you describe can easily be verified by looking at the circuit boards. Usually, missing features depend upon extra chips that simply are not installed, and changing the firmware alone cannot hope to enable every feature. Granted, there are firmware-only features that are offered for extra cost, but these can always be recognized because the specific features in question are available at the time of purchase. Rest assured that Tesla is offering every trick they have. I also happen to trust that the motor windings are indeed different, not to mention more expensive to produce, and it is not a mere firmware change that creates the Sport.

 

[smorgasbord]

It's on the order of 0.2 seconds, for a non-Sport at least.

So if my non-Sport lives up to its 0-60 in 3.9 seconds spec, then in Standard mode it's 4.1 seconds?

And so my car in Performance mode is about as fast as a Sport in Standard?

 

[S-2000 Roadster]

Here's my take:

I cannot imagine that they are hand winding all the motors. Hand winding is very expensive. I can't believe they would give that away for "free".

The other option for everyone getting the same thing would be, of course, if no one is getting a hand wound motor.

Of course, I also have no idea what they are doing.

I totally agree with your take. Basically, what you're saying fits with Occam's razor: "the simplest explanation is most likely the correct one." We know for certain that AC motors can be wound by hand and by machine. We also should be able to accept that there is a difference in performance if the windings are different. Once you accept that it is possible for two motors that appear identical on the outside, but which have different windings on the inside, to in fact be different motors ... well, I stop questioning Tesla's claims at that point. There simply is no reason to assume that they could make every Roadster perform at Sport levels and are too stupid to offer the option as an upgrade to non-Sport owners.

Keep in mind that nearly every option is available to owners as an upgrade, and the various Tesla Stores are more than willing to take your money for parts and labor to add these options. With few exceptions (which are easily explained), you can get anything that's missing from your Roadster added later. Considering the theory that the Sport is nothing more than a firmware upgrade, we'd certainly see Tesla Store service departments busy with just such an upgrade if it were true. The absence of any evidence tells me that it's more than firmware, and you really need the windings on the rotor to get the Sport performance.

Aside: When the Roadster 2.5 appeared with improved sound treatments and a quieter ride, many of the Roadster 1.5 and 2.0 owners in my area rushed in to the Tesla Store to get this 'upgrade' installed. You can be sure that if they could get Sport performance with a mere firmware upgrade, then they would have done so already.

 

[S-2000 Roadster]

So if my non-Sport lives up to its 0-60 in 3.9 seconds spec, then in Standard mode it's 4.1 seconds?

And so my car in Performance mode is about as fast as a Sport in Standard?

I think your original question was vague, in that it could be interpreted two ways, and thus the answer wasn't the one you were seeking.

 

[S-2000 Roadster]

Now, here's a conspiracy for you; if the Sport is more powerful, how come both power gauges are calibrated to 200KW?

Haven't you ever driven a sports car so fast that you buried the speedometer needle at the 'maximum'? It is possible for a car to go faster than the highest reading on the gauge. This is especially true with older cars, or cars which do not show anything beyond about 70 mph for legal/liability reasons. Even the non-Sport Roadster can exceed 200 kW if you trust the 215 kW specifications, and thus I just assume that the needle is pegged by the pin in the guage.