# Track Mode in Snow



## BostonPilot (Aug 14, 2018)

It hasn't been very snowy in Boston this year. Today was the first day I really got to play in the snow. We got about 6-8 inches overnight and the roads were still being plowed as of 5:30... I took my daughter to work rather than her drive her Volt... it's not that great in the snow. The Performance Model 3 with the Pirelli Sottozero winter tires has great grip in the snow.

In any case, I took her to work in regular "Drive" and the car behaved fine. One thing I don't like about all modern cars with stability systems is that when they get just a little sideways, the system gets very aggressive about returning the car to straight and level... it tends to be very abrupt, not at all fun or pleasant. But it's not just the Tesla, all my recent cars have had this issue. Of course, with the other cars (Subaru STi and Ford Focus RS) I could just turn the systems off, which of course you can't do with the Tesla (without a CAN bus defeating device).

In any case I took back roads home from dropping off my daughter and used Track mode to see what the difference would be. It was much more enjoyable as you can definitely throw the car into a turn with some power and get the back end out, without ever feeling like it's going to get away from you (which I attribute to the Sottozeros). There is a point where the stability system kicks in, which is still annoying, but it lets you get a lot closer to the edge before it does anything, and it seems a bit less abrupt when it does start interfering. It feels like it's mostly using the outside brakes to straighten the vehicle back out which isn't terrible if not exactly desirable.

Without having to shift, and with (probably much less than) 450 horsepower on tap the car accelerates quickly when the traction is there so you can go from reasonable to unreasonable speeds quickly which is nice... but frustrating when the traction control ignores the pedal to the floor and decides to limit acceleration. Sigh.

The additional regen from Track Mode is very welcome. If you're on a downhill and let off the car feels unsettled for about 1/4 second as the regen kicks in, and then immediately feels responsive and under control. There's never a feeling like the regen is going to yaw the car. The only thing I have against it is that in long downhills it backs off the regen fairly quickly forcing you to get on the brakes if you're trying to get slower. It's not a big thing, just not sure why it seems to chicken out when it's doing such a good job at first.

The car still has the same problems as all modern cars in deep snow - the ABS is way too aggressive in order to prevent lockup, so you can't get as much braking in the deep snow as you would in older cars (my 2005 STi was fine in deep snow even though it had ABS, my 2017 STi less good). In addition, the traction control prevents acceleration in low friction areas, even with the pedal to the floor. Again, something I would encounter in my STi and Focus RS, except in those cars you could defeat the system. There were several times this morning where I had the pedal to the floor and the car was barely accelerating because of the snow. From experience I know it would have accelerated at least twice as hard if it would have allowed a little wheel spin. I don't blame it, the algorithms don't know I'm in snow... I just wish there was a way to tell it!

Anyway, it was lots more fun to drive in Track Mode in the snow than regular nanny mode. I hope we get some more snow to play in this year!


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## garsh (Apr 4, 2016)

Interesting. This is the first report I've heard saying that the nannies in Track Mode are too aggressive.

https://www.popularmechanics.com/ca...45757/tesla-model-3-winter-driving-rally-car/

http://www.xautoworld.com/tesla/model3-snow-rally-story/


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## BostonPilot (Aug 14, 2018)

Ah, those were fun articles to read. As for the nannies, depends on which part of my posting you're responding to.

The limit on acceleration was very annoying... But the STi & Ford Focus RS were the same (except you could turn it off). On days like today where the temperature is with a degree or two of freezing, the snow is slick but a little wheelspin digs down to the pavement and gives you good acceleration. Except the Tesla won't do that. In some cases this morning the Tesla was limiting the power to where the acceleration was almost zero despite the pedal being all the way down... This is mostly at slower speeds... as the speed builds towards 40 and beyond then the acceleration improves... but at low speeds it's frustrating to have the pedal to the floor and have the car refuse to put power to the wheels.

What I meant about "when the stability system kicks in" is that several times when I was in a drift under power using the steering wheel to maintain the line I wanted, I would feel a sudden (unwanted) yaw which I interpreted as the stability system using the outside brake to decrease the yaw... Not sure if I'm explaining it well, but I had plenty of yaw authority with the steering wheel, but sometimes when turning to decrease the yaw a bit suddenly I would feel the brake activating to yaw the nose. The point is that the steering wheel was doing just fine, but for some reason the stability system jumped in to assist, and the subsequent correction was more than desired.. so it then required a quick opposite response on the steering wheel in order to maintain the line.

On the subject of rejen I talked about it feeling fine and not yawing the car, and I should have been more explicit that I meant during a downhill straight ahead lift of the accelerator. As one of those articles mentioned, if you're in a turn and you let off it definitely kicks the back end out a bit, but it feels good when it does that... So, no complaint there. My only question about the regen is why it seems to decrease on a long downhill... it's not my imagination - a quick look at the green/black power bar would show only a very slight green bar compared to the other times I would lift off. Almost felt like cold-battery-regen (but it wasn't).

There's also an interesting effect at moderate speeds (say, 40 mph) almost like torque steer: whenever I would hit the accelerator at moderate speeds I would get a yaw of the car (I think it was to the left, but now I can't remember). Nothing through the steering wheel, just a yaw of the car. Easily controlled with the steering wheel so not a problem at all. Just a little curious what in the drivetrain setup is causing that.

In any case, it's much better in Track mode than in normal mode, and I really don't expect the stability algorithms to work perfectly in a corner case like snow... I still would like a way to totally turn the stability and traction systems off (and ABS!!) ... Every other car, including my Honda Fit EV let you defeat the stability and traction systems. Not sure why Tesla doesn't?


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## garsh (Apr 4, 2016)

@Mad Hungarian , you might find this interesting as well, and perhaps have something to add.


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