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Disable traction control and all nannies with dyno mode

andrewsjra

Member
Dec 30, 2018
181
62
San Jose
The big question is has someone actually put their model 3 on a dyno in dyno mode to see what the readings are? Especially curious for those with the power acceleration boost.
 
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dsgerbc

Member
Jun 4, 2019
499
347
Michigan
Finally got to try the dyno mode in a bit of snow we got. Couldn't log anything since my OBDLink adapter decided it needed a rest, and I couldn't see wheel speed data in ScanMyTesla anyway (hope it's available soon). Basically, I'd call the dyno mode the donut mode, cause it's the only thing it's good for.
 

camalaio

Active Member
May 28, 2019
1,483
2,094
Vernon, BC, Canada
That could be, but a couple of things...

1. Foot must be on brake the entire time

2. Car must be in Park

3. Left turn signal stalk must be held down the entire time (all the way until you press the Enter button)

I somehow missed the foot on brake part. Thanks! It worked.

I pulled over multiple times to ensure no other vehicles were around me in this mode. One thing I noticed is that the drivetrain has more momentum than you'd think for an electric car. Since it can spin up so fast before you react, it actually takes an uncomfortable amount of time to come back down and give you traction. Don't be flooring it around corners in this mode: once it's gone, it's gone. I won't be using this mode again now that I've got answers to what I was wondering.

Anyhow, I made a terribly interesting observation which is the whole reason I wanted to try this mode. Maybe this deserves its own thread.

This statement was of interest to me:
"Force the torque split to be as it would be under normal straight‐line driving conditions"​

I didn't think that was worth calling out unless it did something like a 50/50 split, but that's not the wording of it. That said, I figured that probably was the case and really wanted to verify since a few have stated there would be physical limitations to doing so (the motors fighting each other, basically).

With almost certainty, on an AWD model, this mode will always use both motors regardless of accelerator input amount. For those unfamiliar, an AWD Model 3 is basically a RWD until you accelerate modestly. IMO, this has been rather non-ideal for icy driving situations (not necessarily snow, but it depends on the type and available grip). That is, when driving gently in Winter, your AWD Model 3 is a RWD most of the time.

I confirmed a few ways:
  • The front motor sounds like it's being used. I'm familiar with the sounds of the vehicle since I rarely listen to music. While coasting at any city speed (<50km/h, that's the only place I felt comfortable testing this), I could hear the front motor whine that is normally only heard while accelerating modestly.
  • On a very icy surface (basically the whole drive), my front end slid out accelerating from a stop.
  • A straight, gentle pull on a snowy surface was faster than if I wasn't using this mode. The amount applied would normally only engage the rear, which would slip and then involve the traction program. It pulled away much better than that without much scratch, so it had to be using the front motor as well.
I find this so interesting because one of the arguments against a full-time AWD "snow mode" (i.e. always use front motor) is that the motors would probably fight each other and result in bad driving behaviour. I was driving on pure ice on a sideways-sloped surface and the car was going straight just fine. If there was even a small torque mismatch, one of the ends would have slid out on me. I cannot convey just how slippery the road was.

After this drive, the only valid criticism of using the front motor full time seems to be the noise. It is absolutely noticeable. I personally don't mind it, especially if it was behind a "snow mode" toggle or something. Perhaps efficiency as well, though that was hard to evaluate considering I also did not have regen. I did about 240 Wh/km instead of the normal 190 Wh/km that this trip would require in the current conditions. Short hills were involved, so lack of regen definitely was part of the equation.

Hopefully someone else finds the above interesting. If anyone has hard info to corroborate or deny (e.g. ScanMyTesla) it would be much appreciated.

EDIT: As a bit of a funny, I had preheated the car for a while before making this errand and got full regen ability despite the cold. And then proceeded to drive in this mode without regen, thus wasting energy heating the pack for nothing. Whoops.
 

cOoTeR

Member
Aug 31, 2019
279
343
Arizona
I tried it on the track the other day. I find it interesting that the "Dyno" warning is to not drive the vehicle on public roads rather than to only use it on a dyno.

I was expecting it to be a lot more unpredictable than it was. In my opinion it was just like driving an old powerful car that didn't have traction control.

The track I was at had a drag strip that runs onto the straightaway. When the track direction is clockwise the drag strip is how you enter the track. I pulled out onto the unprepped strip a little past the starting line in dyno mode. I stopped the car then floored it to see how it would react. The car took off fast. I could feel it break loose a little but it never felt squirrelly.

I slowed up heading into the first turn expecting it to be really hard to handle. I treated the first few laps like I was driving a new car on the track for the first time. I wasn't driving all out but I was still driving at a decent pace. Respecting the electric torque and easing into the throttle kept it pretty tame.

I gradually got more and more aggressive with the throttle inputs, trying to find the limit. At some point I noticed that my lap times were within 2 seconds of my best lap earlier and I wasn't trying to go fast. I stepped it up a little every curve getting more aggressive with the throttle and steering inputs trying to get it to get a little out of control. I was able to induce pretty controllable and predictable slides. It was definitely easier to drive hard with the TC off than my old stock C6 Corvette and my 473whp Camaro were. I got to the point where I was confident enough mid corner to punch it. That's the only time it really broke loose and stepped out but it was still manageable.

I was getting pretty good at feeling when the rear would slide and how much throttle modulation was needed to get the car to rotate to get pointed down the straight. After getting the car pointed it would still accelerate hard down the straights.

After getting done I looked at my lap times. Before going out in dyno mode my fastest lap was a 1:21.97. Not being smooth and sliding the car around in dyno mode my fastest lap was 1:21.95. That's not much of a difference but I'm pretty confident that I can do faster if focus on being smooth and not trying to slide the car every corner. I'm driving the car to Vegas this weekend and need the tires to last so I didn't want to go out and keep beating on them. Otherwise I would have gone back out and tried to get a true fast lap in.

I really expected the car to be a lot more like a drift car. But if you respect the electric torque and are smooth with your inputs it's very controllable. But if you go out and try to slam the throttle mid corner at low speed your going to lose control.

I was trying to edit a video with 3 views of my dyno mode session together but the editing software keeps freezing the videos so I'll have to upload them separately.
 

raptor5244

Active Member
May 10, 2019
1,062
785
Florida
I tried it on the track the other day. I find it interesting that the "Dyno" warning is to not drive the vehicle on public roads rather than to only use it on a dyno.

I was expecting it to be a lot more unpredictable than it was. In my opinion it was just like driving an old powerful car that didn't have traction control.

Sounds like fun but keep in mind you have experience pushing cars to their traction limits and you are on track. Many folks don't have experience with older high powered cars that have no stability or traction control. Not sure what tires you are running but that will make a difference for sure.

The AWD and RWD models do not have the same sticky tires as the M3P+ so with instant torque and lack of experience it is every easy to do what this guy did in the video posted earlier in the thread. IMO, Tesla should create a Sport Drive Mode that "relaxes" the Stability and Traction Control vs. this mode that completely disables everything. This way the car will get a little loose but keep you our of trouble for the most part. The 3P models at least have Track Mode to play with but the AWD and LR guys will try this mode and accidents like this will occur.

 

cOoTeR

Member
Aug 31, 2019
279
343
Arizona
Sounds like fun but keep in mind you have experience pushing cars to their traction limits and you are on track. Many folks don't have experience with older high powered cars that have no stability or traction control. Not sure what tires you are running but that will make a difference for sure.

The AWD and RWD models do not have the same sticky tires as the M3P+ so with instant torque and lack of experience it is every easy to do what this guy did in the video posted earlier in the thread. IMO, Tesla should create a Sport Drive Mode that "relaxes" the Stability and Traction Control vs. this mode that completely disables everything. This way the car will get a little loose but keep you our of trouble for the most part. The 3P models at least have Track Mode to play with but the AWD and LR guys will try this mode and accidents like this will occur.

I'm not saying it is going to be easy for everyone. Just that it isn't completely uncontrollable like I thought it would be. If someone has never driven a powerful car without traction control they can get in trouble. But it is no different then other powerful cars, other than not having the sound of the engine to associate with when it breaks loose. I was on the factory ps4 tires on the rear and Nitto 555G2s on the front.

Here are a couple of the videos.

In car view.

View through the windshield with gps overlay.
 

Daniel in SD

Well-Known Member
Jan 25, 2018
6,344
9,011
San Diego
I never thought I’d be posting the “this problem is not unique to Tesla” post.
Sounds like if you learn to drive and save it for the track you’ll be fine.
 
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dsgerbc

Member
Jun 4, 2019
499
347
Michigan
I never thought I’d be posting the “this problem is not unique to Tesla” post.
Sounds like if you learn to drive and save it for the track you’ll be fine.
The track isn't gonna have too many unpredictable grip variations, short of spilled fluids or people bringing dirt back on to the racing line. It's those grip variations that make open diff AWD/RWD cars unpredictable. On the street in the snow/ice, those grip variations are all over the place.
 

raptor5244

Active Member
May 10, 2019
1,062
785
Florida
I'm not saying it is going to be easy for everyone. Just that it isn't completely uncontrollable like I thought it would be. If someone has never driven a powerful car without traction control they can get in trouble. But it is no different then other powerful cars, other than not having the sound of the engine to associate with when it breaks loose. I was on the factory ps4 tires on the rear and Nitto 555G2s on the front.

I hear ya. I am a big advocate of Tesla letting us disable the nannies if we want but you would think they would create a middle of the road option first. :) By the way, how is the regen in Dyno Mode? Is it completely disabled?
 

raptor5244

Active Member
May 10, 2019
1,062
785
Florida
I think you typed your post inside of the quote. But as far as I remember the regen felt like normal.

Yeah, good catch. That is good to know. I was trying to make sense of this statement in this article.

Tesla Dyno Mode Transforms Any TSLA Vehicle into a Serious Drift Machine

“When the Stability Control and Traction Control systems become faulted, as is the case on a dynamometer where driving is detected but movement is not, regenerative braking is disabled so that unintended braking torque does not lead to loss of traction or control on low friction surfaces. Disabling Stability Control and Traction Control prevents those systems from disrupting regenerative braking behavior, maintaining the most representative driving energy consumption.”
 

cOoTeR

Member
Aug 31, 2019
279
343
Arizona
Yeah, good catch. That is good to know. I was trying to make sense of this statement in this article.

Tesla Dyno Mode Transforms Any TSLA Vehicle into a Serious Drift Machine

“When the Stability Control and Traction Control systems become faulted, as is the case on a dynamometer where driving is detected but movement is not, regenerative braking is disabled so that unintended braking torque does not lead to loss of traction or control on low friction surfaces. Disabling Stability Control and Traction Control prevents those systems from disrupting regenerative braking behavior, maintaining the most representative driving energy consumption.”
My take on that is when they say the systems become "faulted" they are talking about people unplugging the wheel speed sensor that creates a fault that turns the systems off. When that happens regen is disabled as well for safety. The second part of that is that is by "disabling" them (by using dyno mode) regen is still active so the car it's accurately representing what it does on the street. They mention "consumption" as well. So considering this is from something filed with the EPA about dynos and consumption I assume it's about using a dyno to measure the range of the car. Because if someone was to use a dyno as a controlled environment to test the Tesla's range by disabling the wheel speed sensor they wouldn't have regen so the range will show as less than actual. It seems almost like it is the opposite of the VW TDI dyno / emissions testing issues.
 

cOoTeR

Member
Aug 31, 2019
279
343
Arizona
The track isn't gonna have too many unpredictable grip variations, short of spilled fluids or people bringing dirt back on to the racing line. It's those grip variations that make open diff AWD/RWD cars unpredictable. On the street in the snow/ice, those grip variations are all over the place.

I've also driven on the street in dyno mode. There was no drama. The only way this is going to be an issue is if someone goes out and is driving in a manner that is intentionally trying to make the car slide. It might be an issue if someone is trying to drive aggressive with it on and doesn't have the skills to do it. Which they shouldn't be doing on the street. I can't think of a time where the traction control has kicked in on the street while driving normally. If someone is driving on snow/ ice the road and tires are colder than normal. They sound be driving with more gentle inputs anyways. But if they are dumb enough to turn on dyno mode on the street in these conditions they are probably going to crash because their intention is to slide the car and they will be too aggressive with their inputs. Not too long ago traction control and abs were unheard of but people managed to drive just fine.
 

Knightshade

Well-Known Member
Jul 31, 2017
11,876
16,336
NC
Not too long ago traction control and abs were unheard of but people managed to drive just fine.


While I agree with you generally, it's fair to note that when they didn't have those controls they were also typically driving relatively low power (especially at low rpms) ICE vehicles...
 

dsgerbc

Member
Jun 4, 2019
499
347
Michigan
I've also driven on the street in dyno mode. There was no drama. The only way this is going to be an issue is if someone goes out and is driving in a manner that is intentionally trying to make the car slide. It might be an issue if someone is trying to drive aggressive with it on and doesn't have the skills to do it. Which they shouldn't be doing on the street. I can't think of a time where the traction control has kicked in on the street while driving normally. If someone is driving on snow/ ice the road and tires are colder than normal. They sound be driving with more gentle inputs anyways. But if they are dumb enough to turn on dyno mode on the street in these conditions they are probably going to crash because their intention is to slide the car and they will be too aggressive with their inputs. Not too long ago traction control and abs were unheard of but people managed to drive just fine.

People generally lived just fine with open axle diff+ locking center diff AWD cars in the past. Most 90s Subies with a stick shift were like that. You're not gonna crash the instant you put it on snow. It's just not a good setup to drive on the edge of traction. One won't have issues until they try to go 'play in the snow,' or try rallycrossing with that setup. It bites uncontrollably sooner or later, regardless of driver skill. No amount of smooth inputs will help if the car gets instantly upset due to sudden grip change.

Now, I have no idea how Tesla in the dyno mode transfers torque front/rear, so it's possible it will behave more like a RWD car with an open diff, which is a lot more predictable than AWD with an open diff. I have done a few logs, but yet to look at them, cause I'm hoping to be able to log wheel speed as well.

I just advise everyone heading out 'to play in the snow' with the dyno mode to expect it to bite you, and leave yourself plenty of run-off. Do not play in the snow with curbs or poles nearby.
 

Tres_Azul

Member
Oct 10, 2019
69
56
Arizona
I can report that the SR+ in dyno mode is a tail-happy, but mostly predictable little beast. Also can report that if you let regen kick-in whilst sliding, you better have fast hands/feet and lots o' room. Fun, but not OK for the street/daily, especially if one habitually drives like a jerk.

I believe this is the first car where I won't be disabling the nannies immediately upon entering it/starting it. Like cOoTeR, I read the input online about dyno mode and was prepared for 'super scary death time' when I tried it. It was not super scary death time*. The car's manners are actually pretty great for an unmodified open dif RWD vehicle with >300 lb. ft. of torque off 'idle'. (off null / null pedal?)

*= UNless, as pointed out by dsgrbc, the surface changed while hooning, then look out, its prolly gonna try and bite... e.g. Taking an aggressive left turn across a concrete drainage trough flanked by rough asphalt was exciting.

EDIT= Can haz spelling
 
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