Optimizing track mode for snow driving

Hello everyone,

I've just returned from Winter Driving School, now that my MYP has track mode. I thought I would share the settings I came up to optimize track mode for high performance driving on snow (high performance here refers fine control, not outright speed).

Here's a video - see below for discussion of settings & analysis.

Before my MYP, I had Audi's and Subaru's that would let me turn off the stability program. That was much more effective in snow than an MY without track mode. I had hoped they'd eventually give us track mode, and that with it, my MY would be able to get into the same ball park for car control as my prior cars. I am happy to report that that is exactly what happened - but it was not a direct, or short path to that goal. If you just want to know the numbers I'll give the spoilers now. Read on if you're interested in why these ended up being the right numbers or in how we got to them.

Notes:

• These settings were with around 200 lbs of cargo in the trunk
• The track had a solid foundation of ice with several inches of snow that we wore through in several spots.
• These bias and regen settings are likely not optimal for either all-ice or all-snow, but they'd be fine as a starting point
• The stability setting is critical, and would be the same for any conditions

Settings:
Front/rear power bias: 30/70% (anywhere between 35/65 and 20/80 was acceptable)
Stability: -9
Regen: 75% on the skidpad, 30-40% on the slalom

IMPORTANT: Watch out for ABS on ice - with regenerative braking on even partially, if you trigger ABS, the car will keep doing ABS after you take your foot off the brake, b/c it still does ABS for regen-braking. That means you can't threshold-brake to get back your grip. Or at least to do it w/ regen on, you would have to actually press the accelerator to the point where the car wasn't braking anymore, reverse-modulate by lifting to brake more, and pressing to brake less. Crazy-making, that was too next-level single-pedal driving for my brain, I didn't try.

Ok, I'll jump directly to the biggest spoiler from all that: the -9 stability setting. It took a lot to get to this.

-10 does not work well because the MY has open differentials, and uses the brakes to force power from a slipping wheel to the other side of the differential (some call this EDL - Electronic Differential Locking). However, Tesla considers this part of "stability," and when stability is at -10, it's completely off. -9 is the magic number because it enables just enough EDL to reliably get wheels on both sides of an axel to spin together, without cutting out power or doing other tricks to stop you from sliding intentionally.

Here's how we came to all the above...

On the first day, my results were really frustrating - about 1/3 of the time, I could initiate controlled oversteer readily, and keep it controlled for 3-8 seconds. 1/3 of the time it wouldn't come easily, I'd have to slam the accelerator to get oversteer, and then it would be wild/uncontrollable. And 1/3 of the time the car just wouldn't do anything except just keep going slowly in whatever direction I was pointing it, with no understeer or oversteer, no matter how hard I pressed the accelerator.

I tried many combinations of settings that day, ranging from 50/50 to 20/80 bias, 30-80% regen, and -10, -7, and -6 stability. The other tweaks only had a minor impact on how often or how long I could maintain controlled oversteer, or how likely I was to wildly oversteer & spin out. There was no happy medium - always a split between too much, not enough, and always unpredictable.

We had a social event that evening, and I had a great super technical conversation and super constructive conversation with one of the instructors. We had several theories:

1. Maybe even with stability as low as I can put it, the car is still doing some stability control
2. Maybe there is a timer, and it's only willing to let me spin wheels wildly for a limited time
3. Maybe part of the problem is that when the details are just right, and open differential can still spin both wheels (like if they have exactly the same amount of grip and are going the same speed when you overpower them)
4. Maybe the built-in "Drift Mode" setting - which you can not edit, but you can see what settings it is using - has a hidden change that it does that is not available to me in the custom settings

So, we came up with the following experiments to answer the above questions, and he let me go out to the track early on day 2 to conduct them:

1. Get on some ice, point the car straight, and floor it for a long time. See if it eventually cuts power
   1. It did not
2. Same as above, but have observers on both side of the car - see if all four wheels are spinning at the same time
   1. They were not. Sometimes wheels on both sides of an axel would spin, other times it would go back & forth between one side and the other.
3. Turn on Drift mode, and see if I was maintain a continuous drift without it ending except by my choice
   1. I was
4. Duplicate Drift mode's settings in a custom setting group, and see if I was still able to maintain continuous drift (thus proving or disproving whether the built-in Drift mode has a special hidden setting)
   1. I was, and thus, it does not.

Armed with all of the above information, the instructors all concluded that the car still has some kind of traction or stability control going on, even when it's set to -10. I was not convinced. The one thing we didn't have an experiment for was to determine whether the inconsistent results were simply because an open differential has inconsistent behavior.

That is when I thought of trying -9. It was more of a hail-mary, I never believed it was going to work. My thinking was this:

• If an open diff sometimes will still spin both wheels, then maybe all the times I was able to cause oversteer, it is because in those cases, by chance, I got both wheels to spin.
• I had a feeling that the alternating spinning and stopping of wheels that they reported during the straight-line acceleration test was because as I moved forward (slowly b/c of all the slipping), a wheel that was once on ice would eventually find snow, and if the opposite wheel was then on ice, I'd expect the slipping to switch from one wheel to the other
• Maybe, with a lot of luck, if I add the smallest amount of stability programming that I can add, it will bring in just enough EDL to force both wheels to spin whenever one is spinning, but not so much as to prevent me from getting the car to slide.

Well it worked! We did one more test:

• Straight-line floored acceleration with observers on both sides, and front/rear bias at 50/50
  • All four wheels spun continuously until I took my foot off the accelerator!

After that, I tried 25/75 front/rear bias and hit the skid pad again. For the first time, I was able to "drift" in all-wheel-drive mode for as long as I wanted, and it worked every single time. We never did bother to figure out why Drift Mode also enabled this, even though it uses a Stability setting of -10. I think it is a combination of me already being moving and turning before flooring it, and turning off the front motor means the equation for keeping wheels on both sides of the read differential became much simpler.

 

[Madsen203]

Excellent post.

 

[tm1v2]

This is great! Thank you for the detailed experiences and recommendations, and also just for getting out there and really putting the dual motor AWD + Track Mode to use.

 

[gx9901]

Hello everyone,

I've just returned from Winter Driving School, now that my MYP has track mode. I thought I would share the settings I came up to optimize track mode for high performance driving on snow (high performance here refers fine control, not outright speed).

Here's a video - see below for discussion of settings & analysis.

Before my MYP, I had Audi's and Subaru's that would let me turn off the stability program. That was much more effective in snow than an MY without track mode. I had hoped they'd eventually give us track mode, and that with it, my MY would be able to get into the same ball park for car control as my prior cars. I am happy to report that that is exactly what happened - but it was not a direct, or short path to that goal. If you just want to know the numbers I'll give the spoilers now. Read on if you're interested in why these ended up being the right numbers or in how we got to them.

Notes:

• These settings were with around 200 lbs of cargo in the trunk
• The track had a solid foundation of ice with several inches of snow that we wore through in several spots.
• These bias and regen settings are likely not optimal for either all-ice or all-snow, but they'd be fine as a starting point
• The stability setting is critical, and would be the same for any conditions

Settings:
Front/rear power bias: 30/70% (anywhere between 35/65 and 20/80 was acceptable)
Stability: -9
Regen: 75% on the skidpad, 30-40% on the slalom

IMPORTANT: Watch out for ABS on ice - with regenerative braking on even partially, if you trigger ABS, the car will keep doing ABS after you take your foot off the brake, b/c it still does ABS for regen-braking. That means you can't threshold-brake to get back your grip. Or at least to do it w/ regen on, you would have to actually press the accelerator to the point where the car wasn't braking anymore, reverse-modulate by lifting to brake more, and pressing to brake less. Crazy-making, that was too next-level single-pedal driving for my brain, I didn't try.

Ok, I'll jump directly to the biggest spoiler from all that: the -9 stability setting. It took a lot to get to this.

-10 does not work well because the MY has open differentials, and uses the brakes to force power from a slipping wheel to the other side of the differential (some call this EDL - Electronic Differential Locking). However, Tesla considers this part of "stability," and when stability is at -10, it's completely off. -9 is the magic number because it enables just enough EDL to reliably get wheels on both sides of an axel to spin together, without cutting out power or doing other tricks to stop you from sliding intentionally.

Here's how we came to all the above...

On the first day, my results were really frustrating - about 1/3 of the time, I could initiate controlled oversteer readily, and keep it controlled for 3-8 seconds. 1/3 of the time it wouldn't come easily, I'd have to slam the accelerator to get oversteer, and then it would be wild/uncontrollable. And 1/3 of the time the car just wouldn't do anything except just keep going slowly in whatever direction I was pointing it, with no understeer or oversteer, no matter how hard I pressed the accelerator.

I tried many combinations of settings that day, ranging from 50/50 to 20/80 bias, 30-80% regen, and -10, -7, and -6 stability. The other tweaks only had a minor impact on how often or how long I could maintain controlled oversteer, or how likely I was to wildly oversteer & spin out. There was no happy medium - always a split between too much, not enough, and always unpredictable.

We had a social event that evening, and I had a great super technical conversation and super constructive conversation with one of the instructors. We had several theories:

1. Maybe even with stability as low as I can put it, the car is still doing some stability control
2. Maybe there is a timer, and it's only willing to let me spin wheels wildly for a limited time
3. Maybe part of the problem is that when the details are just right, and open differential can still spin both wheels (like if they have exactly the same amount of grip and are going the same speed when you overpower them)
4. Maybe the built-in "Drift Mode" setting - which you can not edit, but you can see what settings it is using - has a hidden change that it does that is not available to me in the custom settings

So, we came up with the following experiments to answer the above questions, and he let me go out to the track early on day 2 to conduct them:

1. Get on some ice, point the car straight, and floor it for a long time. See if it eventually cuts power
   1. It did not
2. Same as above, but have observers on both side of the car - see if all four wheels are spinning at the same time
   1. They were not. Sometimes wheels on both sides of an axel would spin, other times it would go back & forth between one side and the other.
3. Turn on Drift mode, and see if I was maintain a continuous drift without it ending except by my choice
   1. I was
4. Duplicate Drift mode's settings in a custom setting group, and see if I was still able to maintain continuous drift (thus proving or disproving whether the built-in Drift mode has a special hidden setting)
   1. I was, and thus, it does not.

Armed with all of the above information, the instructors all concluded that the car still has some kind of traction or stability control going on, even when it's set to -10. I was not convinced. The one thing we didn't have an experiment for was to determine whether the inconsistent results were simply because an open differential has inconsistent behavior.

That is when I thought of trying -9. It was more of a hail-mary, I never believed it was going to work. My thinking was this:

• If an open diff sometimes will still spin both wheels, then maybe all the times I was able to cause oversteer, it is because in those cases, by chance, I got both wheels to spin.
• I had a feeling that the alternating spinning and stopping of wheels that they reported during the straight-line acceleration test was because as I moved forward (slowly b/c of all the slipping), a wheel that was once on ice would eventually find snow, and if the opposite wheel was then on ice, I'd expect the slipping to switch from one wheel to the other
• Maybe, with a lot of luck, if I add the smallest amount of stability programming that I can add, it will bring in just enough EDL to force both wheels to spin whenever one is spinning, but not so much as to prevent me from getting the car to slide.

Well it worked! We did one more test:

• Straight-line floored acceleration with observers on both sides, and front/rear bias at 50/50
  • All four wheels spun continuously until I took my foot off the accelerator!

After that, I tried 25/75 front/rear bias and hit the skid pad again. For the first time, I was able to "drift" in all-wheel-drive mode for as long as I wanted, and it worked every single time. We never did bother to figure out why Drift Mode also enabled this, even though it uses a Stability setting of -10. I think it is a combination of me already being moving and turning before flooring it, and turning off the front motor means the equation for keeping wheels on both sides of the read differential became much simpler.

View attachment 902093

Awesome post! Winter driving school sounds like fun. Now I'm wondering if there's one around here.

I read through your post and didn't see what kind of tires you have mounted. I assume they are winter tires? What brand/model? Thanks!

 

[dafish]

Well Done Sir!

Now I wish I had track mode. ARGH!!!

 

[Mattemsmy]

great job.that’s a lot of time you put into this.

Now I can only hope that someone somewhere in tesla will understand that us long range with acceleration boost would love to be able to have this car rotate. As soon as my mylr starts to rotate the Nannie’s cut right in. please please loosen up the Nannie’s and let my big girl eat.

 

[Electric700]

great job.that’s a lot of time you put into this.

Now I can only hope that someone somewhere in tesla will understand that us long range with acceleration boost would love to be able to have this car rotate. As soon as my mylr starts to rotate the Nannie’s cut right in. please please loosen up the Nannie’s and let my big girl eat.

I want the best safety with AWD and normal safety features active as I think most Tesla owners would, however it might make sense to have some features in Track Mode adjusted optionally to accommodate those who like to go to racing facilities. There could be one or two buttons underneath Track Mode for that.

 

[kpanda17]

Hello poster, can you be specific for your setting against this image?

for each setting what worked? Or take a photo of your actual display and the settings.
TY

 

[avramd]

Awesome post! Winter driving school sounds like fun. Now I'm wondering if there's one around here.

I read through your post and didn't see what kind of tires you have mounted. I assume they are winter tires? What brand/model? Thanks!

Ah, yes, that was in there originally, but I did a lot of editing. They are Nokian Hakkapeliitta 9's on 18" rims.

As it turned out, they were not even close to the best tires at the track. That is partly b/c they are on their third season, so the studs are a bit worn and the tread-block edges are rounded now. But some of the cars there had absolutely amazing grip, more than I would have even expected from these when they were new. Those people had different versions of "stud-less ice tires."

Blizzaks were the original, and having tried them once, swore I'd never touch them again - their dry performance was horrifying. They were super squirrelly, even in just normal driving, I felt like I was on the verge of losing control on any turn above about 30mph. It seems that this technology has gotten better. I'm on the hunt now for Nokian Hakkapeliitta R5's - they have what they call "arctic crystals," microscopic bits of sharp material embedded in the rubber. The idea is that the entire tread can actually grab the ice at a microscopic level, not just where the metal studs are, and that it is all through the rubber, so as the tires wear, fresh crystals emerge as the old ones wear away. Apparently they do not have the turn-in issue of the original Blizzaks, which seams plausible.

 

[avramd]

Hello poster, can you be specific for your setting against this image?

for each setting what worked? Or take a photo of your actual display and the settings.
TY

Sure, here you go:

 

[gx9901]

Ah, yes, that was in there originally, but I did a lot of editing. They are Nokian Hakkapeliitta 9's on 18" rims.

As it turned out, they were not even close to the best tires at the track. That is partly b/c they are on their third season, so the studs are a bit worn and the tread-block edges are rounded now. But some of the cars there had absolutely amazing grip, more than I would have even expected from these when they were new. Those people had different versions of "stud-less ice tires."

Blizzaks were the original, and having tried them once, swore I'd never touch them again - their dry performance was horrifying. They were super squirrelly, even in just normal driving, I felt like I was on the verge of losing control on any turn above about 30mph. It seems that this technology has gotten better. I'm on the hunt now for Nokian Hakkapeliitta R5's - they have what they call "arctic crystals," microscopic bits of sharp material embedded in the rubber. The idea is that the entire tread can actually grab the ice at a microscopic level, not just where the metal studs are, and that it is all through the rubber, so as the tires wear, fresh crystals emerge as the old ones wear away. Apparently they do not have the turn-in issue of the original Blizzaks, which seams plausible.

Cool, thanks for the feedback on the tires. I do hope the Blizzaks are better now, since I put a set on my daughter’s Subaru for the winter, haha!

I’ve got a set of Michelin X-Ice Snows/19” wheels on my MYP. I have no idea how they rate against other winter tires. They seem to work fine in MN winters, but it would be great if I could some day test them out on one of those winter driving schools.

 

[avramd]

Thanks everyone for the acknowledgements & appreciation!

 

[Mattemsmy]

I want the best safety with AWD and normal safety features active as I think most Tesla owners would, however it might make sense to have some features in Track Mode adjusted optionally to accommodate those who like to go to racing facilities. There could be one or two buttons underneath Track Mode for that.

I want a safe car however there are times and places I like to drive this car. I have been a driver for over 35 years. over 20 track days and tons of auto cross days along with finishing in the top 5 of scca seasons. I can drive this stupid tesla better than the computer the collision avoidance Nannie’s and traction control Nannie’s are for the people that can’t drive Or don’t pay attention while they are driving because they are on social media Or yelling at their kids in the back seat. imo

I don’t want an internet argument all Tesla has to do is let us defeat the traction and yaw Nannie’s. It’s my car I should be able to turn them off.

 

[nencmeister]

I want a safe car however there are times and places I like to drive this car. I have been a driver for over 35 years. over 20 track days and tons of auto cross days along with finishing in the top 5 of scca seasons. I can drive this stupid tesla better than the computer the collision avoidance Nannie’s and traction control Nannie’s are for the people that can’t drive Or don’t pay attention while they are driving because they are on social media Or yelling at their kids in the back seat. imo

I don’t want an internet argument all Tesla has to do is let us defeat the traction and yaw Nannie’s. It’s my car I should be able to turn them off.

Nothing wrong with wanting to get the max out of your vehicle. I think they are hesitant because the media would spin it as disabling “safety” features.

I just wanted to add, we need a dedicated and factory tested snow mode from Tesla. This is my first winter with my MYP, I’m running Pirelli snow tires on 18” wheels, and the car handles beautifully in snow and ice. I’m growing to like this car more and more, I was hesitant at first coming from bmw.

 

[kpanda17]

Sure, here you go:

View attachment 902654

Really appreciate it!

 

[avramd]

I want a safe car however there are times and places I like to drive this car. I have been a driver for over 35 years. over 20 track days and tons of auto cross days along with finishing in the top 5 of scca seasons. I can drive this stupid tesla better than the computer the collision avoidance Nannie’s and traction control Nannie’s are for the people that can’t drive Or don’t pay attention while they are driving because they are on social media Or yelling at their kids in the back seat. imo

I don’t want an internet argument all Tesla has to do is let us defeat the traction and yaw Nannie’s. It’s my car I should be able to turn them off.

I don't think their primary concern is safety, there are many other examples of them forcing automation on us. I think they don't let us turn automation off because, IMHO:

• If they allowed it, they would then have a lot of data they could not ignore about how many of us don't like it
• The people who would turn it off are likely the ones producing the most useful data on how it needs to be improved
• They have trouble admitting to themselves that it is as bad as it is
• A lot of their marketing and market capital hinges on the widely believed story that computers either already do, or will soon make much safer drivers than people, and not having significant data to the contrary gives them "plausible deniability."

 

[avramd]

Hey again, I realized that the photo I took of my settings had a significant difference from what I described in my initial write-up, so I thought I would explain that.

We all often rode in other people's cars when it wasn't our turn. It was helpful to to just observe, as well as hear other people getting coached while we weren't actively driving. Towards the end, a woman who was also a student, but races BMW's in the summer, took a few rides with me. I had ridden with her already in her car (a rear-wheel drive 3-series wagon), and she was talking through her thought process on the slalom out-loud for my benefit. At each turn, she would say "Lift, turn, unwind, accelerate... Lift, turn, unwind, accelerate..." like a mantra. It meant:

• Lift the throttle to shift weight to the front wheels, so they will have more grip
• Turn, with the extra grip, to steer the car to the correct side of the next cone
• Unwind the steering wheel so you are not turning anymore
• Only accelerate once you are going straight, b/c you're at the limit, and you don't have enough grip to accelerate while turning

I was extremely sloppy on the slalom towards the end of the day, often already past the next cone before I had recovered enough grip and control to complete my turn around the previous cone. She was trying to coach me through the mantra, and while I understood what she was asking for, I couldn't get the timing right. Part of the problem was that the accelerator was too touchy - with that much instant torque, I couldn't get my foot to make small enough inputs, every time I tried to accelerate, it was too much, and the car slid sideways instead of advancing towards the next cone.

So, I rode with her again when it was her turn. And then I asked her to drive my car during her turn. She did 6 or so laps of the slalom in Molly, with me riding. The first couple were pretty messy while she was adjusting to such a different car. But she did get dialed in, and she was able to finesse the accelerator better than me, and avoid the side slip.

However, as she was iterating, she started leaving out the "Lift" step of the mantra most of the time. The reason was that she was finding the engine braking too much - instead of transferring weight to the front wheels to get more grip for the turn, it was causing four-wheel slip straight-line slip, preventing her from making the turn. So, I started reducing the regen for her to see if she could get her original mantra to work. It did help some, although we didn't really get to find out because part of her own progression is that she wanted to start learning to not lift the accelerator b/c "it is slowing down, and I don't want to slow down." That didn't quite make sense to me (if you didn't need more grip to be able to make the turn, why would they teach us to do that in the first place?) - but she was way more experienced than me on the track, and I was struggling enough to apply what they were teaching on the slalom to Molly, so I didn't want to get into a conversation that might confuse me more.

Anyway, that is how I ended up at the significantly reduced regen setting. It was the result of being on an extremely icy slalom course with an expert driver at the wheel. Every time a car goes around the track, it polishes the ice a little more, so the track gets gradually slipperier as the day goes on. My own later slalom laps were much worse than my earlier ones even though I had originally been improving. By worse, I don't just mean slower, I mean way out of control despite going slower.

I'm going to try a lighter, more supple pair of shoes next time, I was wearing "mud shoes" this time. However I did look what she had on after the session was over, and she was wearing high-heeled fashion boots, so I dunno

 

[tm1v2]

@avramd As someone who used to chase snowstorms and deep snow all winter in AWD Subarus, but hasn't driven an AWD Tesla in the snow ever, I've always guessed that with M3P Track Mode in the snow I'd want 0% regen.

This is because regen in the 3 and Y is apparently heavily biased towards the permanent magnet motor in the rear. This makes sense for efficiency and on pavement it's totally fine, but it's VERY different from the friction brake bias. On the slippery stuff I could see it being problematic, kinda like RWD gas car engine braking.

On the throttle sensitivity front I completely agree the M3P (and I assume MYP) is too sensitive. I can work with it, I get used to it, but even on pavement I barely use a small portion of the pedal travel in normal driving. I wish I could remap the pedal to be more progressive and linear, like I did with my Subarus.

(Yes Chill mode is way better in this regard but as we all know it greatly limits max power too and that's not what I want at all.)

I hope you had a chance to try 4 wheel drifts around turns, with all 4 wheels scrambling for grip...that's one of the most fun parts of snow driving IMO.

 

[avramd]

@avramd ... regen in the 3 and Y is apparently heavily biased towards the permanent magnet motor in the rear.

Interesting, I hadn't heard that. 0% is too little, I want some engine braking so that I don't have to move my foot to initiate weight transfer - but I'll keep a look out for this in future sessions

I hope you had a chance to try 4 wheel drifts around turns, with all 4 wheels scrambling for grip...that's one of the most fun parts of snow driving IMO.

Yes, definitely. One thing I didn't try, b/c I was too task saturated already, was in the drifts where I my oversteer was too much, switching the power bias to the front mid drift. It's not meant as a real-time control, and it's not situated such that it would be easy to change while steering, but it does seem to respond immediately. It seems like it could be pretty effective. When the car is over-rotating, normally there isn't much left you can do but wait. In theory, if you could temporarily send power to just the front wheels, it would only take a moment to reduce or even reverse the car's rate of rotation.

It reminds me of a quote from Wash in the Firefly pilot, when they're being chased by Reavers...

"Here's something you can't do..."

 

[gx9901]

I started looking for some winter driving school around here after reading this thread. Found one that's taught on the same track I've been on 4 times this past summer. It's by the local BMW Car Club of America though, so I had to get a membership to be able to take the course. So I guess I'm now a proud member of a BMW club...without ever having owned a BMW.

Driving school is on 2/25. I can't wait! (hopefully our mountains of snow this winter haven't all melted by then)