Engineering Explained Upgrades To Tesla Model 3 Performance

Explains how the Model 3 rear motor might work.

Jason Fenske, of the popular Engineering Explained Youtube channel, has traded in his Tesla Model 3. His new car, which he says is a huge improvement, is also a Tesla Model 3. The video above doesn’t just fill us in on why he made the switch. It also gets into the inner workings of the Model 3 rear motor and how that played a part in his decision. We’ll give you a quick synopsis here, though, in case you don’t have the time to watch. (We do recommend it though)

When Fenske first got his Model 3 Mid Range rear-wheel-drive he seemed pretty happy with it. It was the most affordable version available, yet still boasted a reassuring 264 miles of EPA-rated range. Sure, there were some issues with it upon delivery that weren’t really acceptable, but those could be dealt with. Still, it didn’t quite seem to spark joy like he had thought it would. The problem, it seems, had to do with the acceleration.

The mid-size Tesla sedan uses a unique type of permanent magnet motor. According to Fenske, it is a permanent magnet switched reluctance motor (PMSRM), which has a higher efficiency while costing less. With no AC induction motor on the front axle — used in the all-wheel-drive versions of the car — the Mid Range rear-wheel-drive version lacked that instant torque that is generally the hallmark of electric vehicles.

Fenske tells us this is because a PMSRM has to deal with a unique phenomenon called torque ripple. In order to this from making acceleration feel uneven, power is meted out in a slightly limited fashion. While still capable of a 5.6-second sprint from 0-to-60 miles per hour, the performance edge felt blunted.

The obvious fix to this situation was the one the affable host took. He traded in his car for a Performance variant. As you can see in the video, he is extremely happy with the new car. Besides having much better panel alignment and only a couple very minor paint issues, it gives him that deeply satisfying instant acceleration response he felt was missing. With 310 EPA-rated miles, it also gives his range a significant boost. Then there are the extra features like “track mode.”

Besides the info in the video, Fenske also answered a couple questions in the text of the video description dealing with the price of everything and how he knows he didn’t get special treatment. We’ve added that just below. Enjoy!

Video description:



I Sold My Tesla Model 3 Mid-Range & Bought A Model 3 Performance!

After driving the Tesla Model 3 mid-range, I regretted not opting to upgrade to the Performance AWD Model 3. The Model 3 mid-range features a unique permanent magnet rear motor, which gives it different driving characteristics versus many other electric cars, including the Model S and Model X, which both use induction motors. This video will cover what the differences in the motors are (front and rear), how this affects the driving characteristics of the car, the mechanical differences between the mid-range and Performance, as well as the overall condition that my Tesla Model 3 Performance arrived in.

How Do I Know I Didn’t Get Special Treatment From Tesla With Paint Repair/Car Exchange?

First off, this seems strange to me, but many have asked if I somehow received special treatment with regards to getting paint fixed, ordering the Tesla, delivery, etc. That’s not how Tesla works, nor myself, but here’s how I know that no special treatment was provided:

1. Both previous videos were filmed before either video was released. I took delivery of the Model 3 Performance BEFORE the video about paint scratches went live. Hence, Tesla had not seen that I had publicly posted paint issues until I already had my new vehicle. The paint video was filmed before I had decided I was going to trade-in the Mid-Range.

2. I specifically selected the vehicle which I bought. I called Tesla to find out what was in inventory, and I selected a red M3P from that inventory, with VIN. Tesla did not choose the new car for me.

3. When I received the Mid-Range with paint scratches, I called Tesla SLC for the fix. I had heard horror stories from friends about the process required to get the paint repaired (multiple body shop visits, coming back worse than before, loss in value from repaint, etc) so I decided against getting the repair and asked Tesla if they could compensate me at all for the damaged paint instead of dealing with the hassle of repair shops. I felt $2,500 was an unjustified payment for the red paint if it arrives defective/scratched. Tesla said they would get back to me about this. They never did before trading in the car.

4. I only put 49 miles on the car before calling Tesla to inform them I wanted to exchange it for the Performance. This was outside of the 3-day return window (we had a bunch of snow after I took delivery, so I waited until snow had melted before driving for the video review, thus no 3-day window). Tesla said they might be able to switch the car due to the special circumstances (71 miles on the odometer, typical 3-day window needs mileage under 500). Then, they told me they could not.

How Much Did All Of This Cost?

– I bought the Model 3 Mid-Range in November 2018. $46,000 base price.

– $2,500 red paint option, $1,500 19” wheel option, and $1,200 delivery. Total: $51,200 – $7,500 tax credit. Actual Total: $43,700

– The trade-in value of the Mid-Range was $43,200. A $500 loss. The $7,500 tax credit can only be applied to the first buyer, so it instantly loses this much in value. Essentially, buying used means getting the tax credit up front.

– I bought the Model 3 Performance in December 2018. $64,000 base price.

– $2,500 red paint option, and $1,200 for delivery. Total: $67,700 – $7,500 tax credit. Actual Total: $60,200

– Total Cost To Upgrade To Model 3 Performance: $17,000



Source: YouTube

This article originally appeared on Inside EVs.

 

[J-Ho]

I’d be curious to see if anyone has an 1/8 or 1/4 mile timeslip for the MR to see if his observations on smoothed our acceleration holds water. Hopefully it’s not true that there is much if any difference between the LR, RWD

 

[ℬête Noire]

I'm more curious if by this fall he sells his S2000 because he finds he's not driving it anymore.

 

[AlanSubie4Life]

I’d be curious to see if anyone has an 1/8 or 1/4 mile timeslip for the MR to see if his observations on smoothed our acceleration holds water. Hopefully it’s not true that there is much if any difference between the LR, RWD

Actually it would be nice to see the VBOX data for the LEMR. A lot of people even complain about the P3D feeling slow off the line, and it may indeed be the case in the very early going (shockingly, there is disagreement about this ). It is difficult to see the P3D slowness in the VBOX data (see the nonlinearity in the plot below below 5mph), but may indeed exist below 5mph, or at about 1ft into the run. (At 0.85g the car is going 5mph at about 30cm - this distance is inversely proportional to the actual initial acceleration so it could be as long as 60cm perhaps - but the typical max g during a run is about 0.85g). EDIT: I guess with a wheel circumference of 7 feet and a 9:1 drive ratio that is a bit more than 1 revolution of the motor in the first foot? Not sure of these numbers.

In any case you can see in the plot that whatever acceleration/torque ripple might be dealt with is resolved by around 5mph for the P3D.

My guess is Jason's complaint with the LEMR slowness is mostly software related. All the cars have the same rear motor. It's true that the front motor could minimize any of the torque ripple issues. So it would be good to see LEMR & LR RWD VBOX data like this, to see if the acceleration actually takes a while to fully kick in as EE claims. Whatever the data says, he did say he thought a big portion of the issue is software. I'm just not sure about how much this torque ripple really matters at speeds above 5mph, is my point. Presumably to the extent it is an issue, Tesla's motor controller is set up to try to mask it. How much that limits the peak torque the motor can produce when this is a real issue, I do not know.

 

[ℬête Noire]

In any case you can see in the plot that whatever acceleration/torque ripple might be dealt with is resolved by around 5mph for the P3D.

I think his contention is:
1) an engineer may mitigate the direct ripple effect by backing off how much they'll dial up the torque
2) in the dual motor Model 3s, then supplement the low end of the acceleration curve by turning up the [less energy efficient] front induction motor

So Tesla can shape the curves of the power application to obscure this. We can sort of induce what may be happening by doing a dyno run that breaks out front torque from rear torque, but I've not seen anyone do that. Dynos typically aren't even set up to measure those very low speeds, as that isn't normally pertinent for ICE vehicle operation because down there you're not in the power band where the car is being operated.

 

[Peteski]

Yep, that acceleration looks pretty consistent and shows no sign whatsoever of being "slow" off the line. From the gradient on that graph, acceleration looks to be a constant value up to around 40 mph and then begins to reduce as the torque drops away.

 

[scottm]

Well, I found that to be a pretty verbose video. I'm not into the yackity-yack style of filling airtime.

Can sum that up in maybe 2 to 3 minutes, if all you wanted was the facts out of it.

If you wanted the 2 whoopie cushion demonstrations that seem to amuse the videographer way more than it should, then watch the whole thing.

 

[AlanSubie4Life]

1) an engineer may mitigate the direct ripple effect by backing off how much they'll dial up the torque
2) in the dual motor Model 3s, then supplement the low end of the acceleration curve by turning up the [less energy efficient] front induction motor

Yes. Agreed, this is exactly as I posted.

It follows, then: For the LEMR/LR AWD it would be interesting to see if the slope is reduced below 10-20 mph (whatever value Jason gave, not rewatching...) to something *well* below the acceleration of the P3D *below* 3mph (which I would estimate to be below 0.5g assuming no measurement error - which there might be at such small position changes). Because at that point you’d have (if he’s right that this is a factor) torque ripple and reduced torque (acceleration) and the P3D should have a lot more than the RWD at those speeds due to the front motor. Seems unlikely that acceleration is that much reduced though.
I think it is mostly perception and the lack of initial jerk that makes people think it is slow. Combined with the software reduced acceleration, makes the LEMR feel slow. It is quite quick but it is also smooth. To me the P3D now feels slow. Oh well.

Still, would be good to see plots. Just to see...

 

[AlanSubie4Life]

Yep, that acceleration looks pretty consistent and shows no sign whatsoever of being "slow" off the line

To be fair, if you look at the first 3-4 data points the slope is lower. Hard to know if it is measurement error related. But by 3-5mph, after 1 foot or so and 0.2 seconds, it is off to the races.

 

[Peteski]

To be fair, if you look at the first 3-4 data points the slope is lower. Hard to know if it is measurement error related. But by 3-5mph, after 1 foot or so and 0.2 seconds, it is off to the races.

I don't think there's really enough data there to say. A lot is happening down at the contact patches in that initial fraction of a second when it starts moving. The fact that it appears to be getting close to its peak acceleration by 5 mph is enough to suggest that there would be no perceivable delay in the cabin. I expect it would snap your head smartly into the head restraint off the line and keep it there up to 50 mph. Not like my uncorked X 75D which definitely has a lower initial rate of acceleration for maybe the first second and then kicks in aggressively thereafter. You really feel it being held back at the start in that car, as if the traction control settings are very conservative.

 

[mongo]

Possibly, they delay power to allow people to realize they are pressing the accelerator and not the brake. May also be a way of extending the lifespan of the CV joints.

 

[SpiceWare]

I'm more curious if by this fall he sells his S2000 because he finds he's not driving it anymore.

A month after getting my Long Range 3 I drove my S2000 around to get quotes to sell it. I initially thought something was wrong as the acceleration wasn't as good as I remembered, and the noise was significantly louder than I remembered.

 

[Krash]

I suspect that what is mistaken by the video author as a delay is simply the initial fixed torque setting being lower. There is no delay in acceleration for either the 3LR or the X75D. The fixed torque simply limits the power output until it is limited by the battery. Since all these are settings, it would make sense that the midrange (for which we do not have data) simply has lower torque and lower max power. Also, traction control does not engage unless on an unusual surface like gravel or ice as the car's tires are matched to this torque and power setup.

I am not arguing that torque ripple would not be observed at really high torque settings. But since it doesn't appear at higher settings in the 3LR, I doubt that the torque curve of the midrange is anything but linear.

 

[AlanSubie4Life]

I am not arguing that torque ripple would not be observed at really high torque settings. But since it doesn't appear at higher settings in the 3LR, I doubt that the torque curve of the midrange is anything but linear.

Agreed. That looks like something around 0.55g (30mph in 2.5sec) for the LR, just looking at the slope. That's not low enough relative to the initial P3D acceleration (which is perhaps 0.55g, if we're not just seeing VBOX measurement error - which is entirely possible) to suggest that torque ripple is the limiting factor for initial acceleration at low RPM for the currently programmed max torque. Though, more of the weight would be on the back wheels during a 0-60 run, so the front motor won't help the P3D as much as one would like. But I'd expect SOME help from that front motor at launch. If anything, initially the LR RWD motor might be putting out the same or more torque than the rear motor (alone) of the P3D (though the P3D has the front motor to help out so it's just as much (probably more) total torque initially and has much more torque after 1 foot).

Though I'm a bit confused by your 0-60 listed times in your spreadsheet, as they don't appear to align with the plots of mph vs. time, which start at negative time. And we can't see the critical first few MPH in your data...

 

[mswlogo]

Duh. Maybe he should have taken a test drive.

 

[ℬête Noire]

Duh. Maybe he should have taken a test drive.

He says exactly that in the video. The reason he didn't do a post-sale "test drive" that Tesla allows, and then returned inside the 3 day window, had to do with weather.

 

[mswlogo]

He says exactly that in the video. The reason he didn't do a post-sale "test drive" that Tesla allows, and then returned inside the 3 day window, had to do with weather.

Test drive before you even buy it. I test drove extensively before deciding. And I still think I made the right choice.
It looks like he didn't take a total bath. But the whole video is kind of silly.

There are good reasons to get a RWD too.

 

[ℬête Noire]

Test drive before you even buy it.

Watch the video.

 

[Peteski]

There is no delay in acceleration for either the 3LR or the X75D. The fixed torque simply limits the power output until it is limited by the battery. Since all these are settings, it would make sense that the midrange (for which we do not have data) simply has lower torque and lower max power. Also, traction control does not engage unless on an unusual surface like gravel or ice as the car's tires are matched to this torque and power setup.

I agree there is no time delay between hitting the pedal and the motor response, but the initial kick (acceleration) on my X75D is still relatively soft (due to the set torque limit) and that's why active traction control doesn't need to kick in as the torque is already limited well below the grip potential of the tyres. Acceleration then ramps up suddenly (maybe at around 5-10 mph) to whatever peak it is set to achieve. It basically feels like a soft start motor. From a rolling start at say 15 or 20 mph it seems to hit max torque more or less instantly with no obvious ramp up like you get from a standstill. It doesn't really show in your graphs.

None of this is a problem for me personally and it makes for a very smooth launch without any traction control scrabbling off the line. P-models I've driven are obviously brutal straight off the line with traction control working hard, but outside of a drag strip it's all fairly academic. What I don't experience in my X is the delay in throttle response that the guy in the video appeared to be complaining about in his MR M3. Other than the slightly soft launch from a standstill, torque response in my X75D is instant from any rolling speed. But from what the guy says in the video it sounds like the MR M3 didn't quite have that "instant torque" characteristic that most electric cars have.

When one UK magazine was comparing the iPace performance against an X100D, the iPace beat the 100D from 0-60 mph by about a car length, but the 100D was notably quicker from a rolling start, easily pulling a few car lengths away, which again suggests a deliberate soft launch holding the 100D back slightly from a standstill.

 

[Peteski]

Though, more of the weight would be on the back wheels during a 0-60 run, so the front motor won't help the P3D as much as one would like. But I'd expect SOME help from that front motor at launch. If anything, initially the LR RWD motor might be putting out the same or more torque than the rear motor (alone) of the P3D (though the P3D has the front motor to help out so it's just as much (probably more) total torque initially and has much more torque after 1 foot).

Even with the dynamic rear weight transfer, the front motor will still be able to put some serious torque through the front wheels as it will be far from pulling a wheelie Remember there are plenty of quick front wheel drive cars out there, even if the weight transfer does favour RWD off the line. Dynamic rearward weight transfer is nothing like as dramatic as lateral weight transfer under cornering, due to the relative long wheelbase vs track and lower longitudinal vs lateral acceleration. If I could be bothered it would be quite easy to work out the dynamic front & rear tyre loads under peak acceleration and then you could get an idea of the front and rear potential contributions to acceleration.