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"Full-Time" AWD Winter Mode

mswlogo

Well-Known Member
Aug 27, 2018
6,044
4,663
MA, NH
In Alaska we don’t use any chemicals or pre treatment to melt snow/ice due to the negative environmental impact. I’m sort of surprised with how liberal MA is that they haven’t banned salt there as well. So I drive on packed snow and ice most of the time around half the year.

Yeah, understood. But my point is how fast would you drive on it? I also know you run studs too. Is it snow pack on the highways up there too?

Lots of people hate the salting. They use mountains of it. Both NH and MA.
 

coleAK

Member
Oct 23, 2018
887
597
Alaska
Yeah, understood. But my point is how fast would you drive on it? I also know you run studs too. Is it snow pack on the highways up there too?

Lots of people hate the salting. They use mountains of it. Both NH and MA.
I don’t go over 55 mph very often in the winter. We don’t have many true stretches of highway as most people in the lower 48 would consider. And yes I’m on studded Hakka 9’s. Roads are rarely so bad I need to go <40 mph on the highway. And much of a typical the highways are snow/ice covered.
 

mswlogo

Well-Known Member
Aug 27, 2018
6,044
4,663
MA, NH
Maybe you don't understand this because you are in S.D. but on very low traction surfaces it's not about the load you don't have, it's about the load you do have. There is always a load or the power distribution just doesn't matter (at all). It's on ice (where the load is very small) that it matters the most.

I think you have a fundamental misunderstanding of what's required to achieve good traction on ice. It's a very delicate thing which is why EV's can be so superior to ICE. Because the electronics allow very precise measurement of load, even at very small values. There is no comparable ability in any ICE car, at least none that I'm aware of.

Looks like someone finally did a thorough test on the AWD of the model 3. Clearly it’s heavily RWD biased. Little disappointing.


I’m sure @StealthP3D will probably say Performance cars are different or something.

I think the Model 3 needs a “Grip Start” instead of a “Slip Start”.
 

StealthP3D

Well-Known Member
Dec 12, 2018
9,201
70,817
Maple Falls, WA
Looks like someone finally did a thorough test on the AWD of the model 3. Clearly it’s heavily RWD biased. Little disappointing.

Too funny! Is that why every auto journalist to ever drive the Model 3 has raved about its superior driving dynamics? And I bet that's why it performed so well for me climbing steep roads covered in snow and ice. The AWD handles snow and ice covered roads like a bat outta hell! I guess it's "disappointing" in the same way the BMW M5 is "disappointing".

EXCLUSIVE: BMW Wants Rear-Biased AWD For Next-Gen M5

"We were told any all-wheel-drive system on the next M5 would have to “deliver the feel and performance like a rear-wheel drive system but with additional traction support.” If that can be achieved “then BMW will consider it for implementation.” This seems to corroborate what the Aussie product specialist told GoAuto regarding the 20:80 torque split, a massive bias towards the rear wheels."

If you have an AWD Volvo, you need to pay thousands of dollars extra to get the rear-bias software upgrade installed! That's right, it's not a free Over-the-Air update, you have to pony up some real money to get rear wheel bias:

Polestar AWD optimisation is going to make Volvos even more fun to drive - AutoBuzz.my

"There is a Polestar tuning package for almost every Volvo vehicle out there that offers sharper throttle response, quicker gear changes and increased engine output. Now, Volvo Cars have just introduced a new Polestar-developed software upgrade that promises a more dynamic driving experience on all-wheel drive (AWD) Volvos.

The optimization software increases the amount and frequency of torque being sent to the rear wheels giving the car sharper turn-ins, better control and engagement in a corner and improved traction when pulling away. All these give the driver a more dynamic and engaging driving experience."

Sounds real "disappointing"!:rolleyes:

Next thing you know, mswlogo will claim it's real disappointing that Tesla increased the peak HP of all Model 3's with a software update. The real "disappointing" part is that you can't even pay for it, it's loaded on your car free of charge! How disappointing. ;)

Maybe if you ask Tesla real nicely they will develop a special mode just for you:

Coming in 2020, a new software downgrade called "beginner mode" applies less torque to the rear wheels giving the car a duller turn-in, worse control and engagement in corners and decreased traction when pulling away. All of these give the driver a less dynamic and engaging driver experience.

This software downgrade was developed specifically for those drivers who are tired of the lively and engaging driving dynamics of the AWD Model 3. A further downgrade to the peak HP and torque will make the car easier to handle and increase safety.;)

Keep in mind that with dual motors it's child's play to move the torque bias from front to rear or vice-versa. It's just a software change. The Performance Model 3 dynamically changes the front/rear bias while driving so a static roller test is pretty meaningless. The best way to experience it is simply to drive the car. On this point, the auto journalists all agree, it's a fine handling AWD car.
 
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Daniel in SD

Well-Known Member
Jan 25, 2018
6,331
8,996
San Diego
Looks like someone finally did a thorough test on the AWD of the model 3. Clearly it’s heavily RWD biased. Little disappointing.


I’m sure @StealthP3D will probably say Performance cars are different or something.

I think the Model 3 needs a “Grip Start” instead of a “Slip Start”.
Thank you! It's exactly like everyone in this thread has been saying.
For people that don't want to watch the video. From a stop with the front wheels on rollers the car accelerated with zero slippage, with rear wheels on rollers that car spins the rears for a while then sends power to the front wheels. The car has a reactive AWD system.
 

Daniel in SD

Well-Known Member
Jan 25, 2018
6,331
8,996
San Diego
Too funny! Is that why every auto journalist to ever drive the AWD Model 3 has raved about its superior driving dynamics? And I bet that's why it performed so well for me climbing steep roads covered in snow and ice. The AWD handles snow and ice covered roads like a bat outta hell! I guess it's "disappointing" in the same way the BMW M5 is "disappointing".

EXCLUSIVE: BMW Wants Rear-Biased AWD For Next-Gen M5

"We were told any all-wheel-drive system on the next M5 would have to “deliver the feel and performance like a rear-wheel drive system but with additional traction support.” If that can be achieved “then BMW will consider it for implementation.” This seems to corroborate what the Aussie product specialist told GoAuto regarding the 20:80 torque split, a massive bias towards the rear wheels."

If you have an AWD Volvo, you need to pay thousands of dollars extra to get the rear-bias software upgrade installed! That's right, it's not a free Over-the-Air update, you have to pony up some real money to get rear wheel bias:

Polestar AWD optimisation is going to make Volvos even more fun to drive - AutoBuzz.my

"There is a Polestar tuning package for almost every Volvo vehicle out there that offers sharper throttle response, quicker gear changes and increased engine output. Now, Volvo Cars have just introduced a new Polestar-developed software upgrade that promises a more dynamic driving experience on all-wheel drive (AWD) Volvos.

The optimization software increases the amount and frequency of torque being sent to the rear wheels giving the car sharper turn-ins, better control and engagement in a corner and improved traction when pulling away. All these give the driver a more dynamic and engaging driving experience."

Sounds real "disappointing"!:rolleyes:

Next thing you know, mswlogo will claim it's real disappointing that Tesla increased the peak HP of all Model 3's with a software update. The real "disappointing" part is that you can't even pay for it, it's loaded on your car free of charge! How disappointing. ;)
All the cars you're referencing have selectable AWD modes...
 
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mswlogo

Well-Known Member
Aug 27, 2018
6,044
4,663
MA, NH
Thank you! It's exactly like everyone in this thread has been saying.
For people that don't want to watch the video. From a stop with the front wheels on rollers the car accelerated with zero slippage, with rear wheels on rollers that car spins the rears for a while then sends power to the front wheels. The car has a reactive AWD system.

Yeah, I’d be curious how fast the front might wake up if you gun it. Obviously a bad idea in this test. But I would expect it must spool up the front quicker on quick accel or they could never reach the benchmarks these cars can get.

It really should have done exactly the same thing with rollers on front vs back.

It might be optimized for spirited dry handling and efficiency but it’s not ideal in Icey conditions and should have an option for slippery conditions.

Know what would have been a good test, is to repeat the test several times back to back. Possibly once the car knows it’s in slippery conditions it may subsequently spool up the front quicker on later rear wheel slippage encounters. I can hear @StealthP3D jumping all over that speculation ;). I doubt it does, but certainly could and probably should if they don’t want to allow a manual option.
 
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Daniel in SD

Well-Known Member
Jan 25, 2018
6,331
8,996
San Diego
Yeah, I’d be curious how fast the front might wake up if you gun it. Obviously a bad idea in this test. But I would expect it must spool up the front quicker on quick accel or they could never reach the benchmarks these cars can get.

It really should have done exactly the same thing with rollers on front vs back.

It might be optimized for spirited dry handling and efficiency but it’s not ideal in Icey conditions and should have an option for slippery conditions.

Know what would have been a good test, is to repeat the test several times back to back. Possibly once the car knows it’s in slippery conditions it may subsequently spool up the front quicker on later rear wheel slippage encounters. I can hear @StealthP3D jumping all over that speculation ;). I doubt it does, but certainly could and probably should if they don’t want to allow a manual option.
I would bet if you gunned it it would send torque to the front wheels instantly. There is a ton of torque going to the front wheels when I've got a heavy foot on the throttle. Too much in fact and it makes me wish I got the Performance.
I think the throttle is just mapped to send torque to the rear wheels for the first X% of throttle (maybe the maximum throttle used in the EPA test :p) and then starts sending torque to the front wheels as well. This results in the best MPGe and the great handling that @StealthP3D is raving about but it's not optimal for snow and ice, especially on crappy all season tires.
Maybe they could use a neural net like they do with the windshield wipers :rolleyes:
 

StealthP3D

Well-Known Member
Dec 12, 2018
9,201
70,817
Maple Falls, WA
Possibly once the car knows it’s in slippery conditions it may subsequently spool up the front quicker on later rear wheel slippage encounters. .

Judging by my extensive experience with my P3D in snow/ice, I don't think they use a variable torque distribution mapping based upon slippage (except as needed on an instantaneous basis via traction control). My observation is the torque distribution mapping is very consistent, even during/after some hooliganisms on a snowy road. And I think I prefer consistency over any kind of attempt to adapt to the conditions as they were immediately preceding any adaptive change. As it is, it's very good at finding the available traction and capitalizing on it. Traction control works basically in real time which is a good thing, it wouldn't be desirable to have it trying to adapt on a more general timescale at the cost of being less consistent in its behavior. It's not difficult to program the desired behavior into the system in real time (and that's what they have done). I wouldn't like it if my car changed it's behavior as I drove it through various conditions, I want consistency.

One thing Tesla will almost certainly add when they have the time/money for the necessary development/testing is to add user-selectable drive modes. They keep adding more features. Not that those who wish to paint Tesla and their products in the most negative light will suddenly be happy and positive, they will simply find other perceived flaws with which to try to take Tesla down a notch. I will definitely experiment with other modes of torque bias when they come out with selectable modes but, in the nastiest snow and ice, I would probably leave it in the current rear-biased setup because this leaves the front end the most planted. Which is exactly what is needed to maintain directional control when traction is super scarce. I like that the rear is tuned to slip easier than the front. This works especially well in the Model 3 due to the battery and motor weight being so evenly distributed front to back. It can be a handful in a front-engined, rear drive fossil car that has an overly light rear-end but works this isn't an issue in the Model 3 with the rear motor between the rear wheels and the battery weight distributed 50/50 front/rear. As you climb progressively steeper hills covered in snow and ice, the weight shifts to the rear wheels which is a primary reason the Model 3 climbs so well in both the RWD and AWD versions. It's also why they don't make a FWD version (thankfully). Don't get me wrong, I like the driving dynamics of a number of FWD fossil cars, but only because the engine is over the drive wheels.
 
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mswlogo

Well-Known Member
Aug 27, 2018
6,044
4,663
MA, NH
Judging by my extensive experience with my P3D in snow/ice, I don't think they use a variable torque distribution mapping based upon slippage (except as needed on an instantaneous basis via traction control). My observation is the torque distribution mapping is very consistent, even during/after some hooliganisms on a snowy road. And I think I prefer consistency over any kind of attempt to adapt to the conditions as they were immediately preceding any adaptive change. As it is, it's very good at finding the available traction and capitalizing on it. Traction control works basically in real time which is a good thing, it wouldn't be desirable to have it trying to adapt on a more general timescale at the cost of being less consistent in its behavior. It's not difficult to program the desired behavior into the system in real time (and that's what they have done). I wouldn't like it if my car changed it's behavior as I drove it through various conditions, I want consistency.

One thing Tesla will almost certainly add when they have the time/money for the necessary development/testing is to add user-selectable drive modes. They keep adding more features. Not that those who wish to paint Tesla and their products in the most negative light will suddenly be happy and positive, they will simply find other perceived flaws with which to try to take Tesla down a notch. I will definitely experiment with other modes of torque bias when they come out with selectable modes but, in the nastiest snow and ice, I would probably leave it in the current rear-biased setup because this leaves the front end the most planted. Which is exactly what is needed to maintain directional control when traction is super scarce. I like that the rear is tuned to slip easier than the front. This works especially well in the Model 3 due to the battery and motor weight being so evenly distributed front to back. It can be a handful in a front-engined, rear drive fossil car that has an overly light rear-end but works this isn't an issue in the Model 3 with the rear motor between the rear wheels and the battery weight distributed 50/50 front/rear. As you climb progressively steeper hills covered in snow and ice, the weight shifts to the rear wheels which is a primary reason the Model 3 climbs so well in both the RWD and AWD versions. It's also why they don't make a FWD version (thankfully). Don't get me wrong, I like the driving dynamics of a number of FWD fossil cars, but only because the engine is over the drive wheels.

Well the car clearly does some dynamic adjustments based on slippage. They adjust regen based on wheel slippage. Now how much else they do dynamically I don’t know. But I bet they do a fair bit.

Be curious what the roller test would do in track mode as well.
 

coleAK

Member
Oct 23, 2018
887
597
Alaska
Thank you! It's exactly like everyone in this thread has been saying.
For people that don't want to watch the video. From a stop with the front wheels on rollers the car accelerated with zero slippage, with rear wheels on rollers that car spins the rears for a while then sends power to the front wheels. The car has a reactive AWD system.

Funny how that works. The masses (all but the one “outlier”) we’re correct. Anyway we had an extremely warm end of March early April with lows around 30 and highs around 40 and rain Up to ~2k feet. Anyway I use my driveway completely melting off as an indicator as when to take off my winter tires since it’s shaded, on the north side of my house, and I’m at ~1000 ft above Anchorage. So in short it’s one of the last roads to melt off. In anticipation of getting the winter tires off to unleash the beast on dry roads This year I took them off a little early. We got hit last week with 6 days straight of snow and over 3’ of new at my house. On day 4 the snow on the driveway was packed down and the streets had been plowed. I was going to “test” the MXM4s on the snow. I couldn’t even make out of my driveway. Rear end spun just like this then front spun. It was futile though as friction had already been broken in the rear.
 

StealthP3D

Well-Known Member
Dec 12, 2018
9,201
70,817
Maple Falls, WA
Well the car clearly does some dynamic adjustments based on slippage. They adjust regen based on wheel slippage. Now how much else they do dynamically I don’t know. But I bet they do a fair bit.

That's why I said the Traction Control is done in real time. I was addressing the idea that Tesla might modify the torque distribution in ways other than real-time. They don't do that as far as I can tell (thankfully).

Be curious what the roller test would do in track mode as well.

The roller test is a nice party trick and that's about all it's good for. If you really want to know how the car behaves at the limit, drive it at the limit!

That's what I did.
 

StealthP3D

Well-Known Member
Dec 12, 2018
9,201
70,817
Maple Falls, WA
Funny how that works. The masses (all but the one “outlier”) we’re correct.

If you are referring to me, I've always said the AWD definitely has a rear-bias, you don't need a roller test to figure that out. It's obvious. That's why the car drives as well as it does.

We got hit last week with 6 days straight of snow and over 3’ of new at my house. On day 4 the snow on the driveway was packed down and the streets had been plowed. I was going to “test” the MXM4s on the snow. I couldn’t even make out of my driveway. Rear end spun just like this then front spun. It was futile though as friction had already been broken in the rear.

LOL! You learned that "All-season" radials are not real snow tires. :rolleyes:
 

coleAK

Member
Oct 23, 2018
887
597
Alaska
If you are referring to me, I've always said the AWD definitely has a rear-bias, you don't need a roller test to figure that out. It's obvious. That's why the car drives as well as it does.



LOL! You learned that "All-season" radials are not real snow tires. :rolleyes:
I didn’t “learn”. It was intentional, Just wanted to see how bad the OEM all seasons were in snow. I switched the tires on the Tesla early because I had to mount the MXM4s to our new rims and also wanted to do the Tesla switch on a frame lift, not with a floor jack l. Basically didn’t want to hit the tire change over rush at the auto hobby shop. We have 4 cars between the 2 drivers in the house the other 3 still have winter tires on.
 

mswlogo

Well-Known Member
Aug 27, 2018
6,044
4,663
MA, NH
I didn’t “learn”. It was intentional, Just wanted to see how bad the OEM all seasons were in snow. I switched the tires on the Tesla early because I had to mount the MXM4s to our new rims and also wanted to do the Tesla switch on a frame lift, not with a floor jack l. Basically didn’t want to hit the tire change over rush at the auto hobby shop. We have 4 cars between the 2 drivers in the house the other 3 still have winter tires on.

I took our snows off on the Model 3 little early too and also left the snows on, on the Jeep a few weeks longer. But I was a lot luckier. Still fairly cool though. Still have days I don’t reach full regen.
 

Shayne

Member
Dec 2, 2019
239
119
North Bay
Read most of it; it is quick once you learn what to skip. Did Tesla ever address the fish tailing noted on this thread? Was there ever a software attempt to allow true awd and not slip and grip? One would think with the weight of these vehicles they should be able to run on snow like a 4x4 truck. Appears not so and winter tires are a must and even then not gr8. Was just looking to see if people were running all seasons like my truck and found out something I did not want to hear. Winter is picking up again; unfortunately we get it for 1/2 the year. Here is hoping the Y is a bit better in the snow.
 

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