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Questions about tracking the car (road course)

Discussion in 'Model S: Driving Dynamics' started by Dreamin, Oct 29, 2013.

  1. Dreamin

    Dreamin Member

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    1. Will using the heater help delay the powertrain from overheating and limiting power? Using ICE logic here: taking the heat from the engine and dumping it into the cabin... not sure if this applies to the Tesla. (Assuming 60-70deg temps)

    2. I understand the high energy use on track (1000+ Wh/mi) produces an artificially low 'rated range' (31 miles left problem)... but is there a way to determine how many easy freeway miles are still left on the battery. I need to leave the track with at least 20 miles left to get to the closest charger. Can I use "Total Energy Since Last Charge" somehow?

    3. TC on or off? I have a lot of track experience, but this is my first time tracking the Tesla and first time at this track.
     
  2. brianman

    brianman Burrito Founder

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    Terminology adjustment: Projected, not rated.

    - - - Updated - - -

    The rated range will display using the normal EPA constant.

    So, for example, suppose you start with 200 rated miles. At the track you burn it at 4x the rated rate, say ~1200 Wh/mi, for 20 miles of distance. Instead of having 180 (200-20) rated miles at the end of track activity, you'll have ~120 rated miles (200-20x4).

    Your "projected" chart on the Energy app will likely show something like ~30 rated miles if you put it on the "last 15 miles" and "Average" settings. If you use "last 30 miles" it will likely be higher than that because 1/3rd of the X axis (30-20) will be "before track" driving.

    Make sense?

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    "Veteran track enthusiasts" tend to say "we like TC off."

    "Newbie track enthusiasts" (like me) tend to say "I leave TC on."
    There are three reasons (for me):
    1. There are situations where TC will "save" you in a trouble spot. This extra safety net is a plus for new experiences.
    2. "You shouldn't really get much benefit out of 'TC off' until you're able to drive it well enough that it matters." (Paraphrasing what instructors tend to say.)
    3. I generally* like to leave settings consistent between track and street, as I want to learn one car configuration (limited time and mental energy) not several. Indeed, part of the reason I moved into this arena (track) was to improve skills for everyday driving -- both for enjoyment and safety.

    * There are exceptions to this general rule. My "plan" is to use different wheels+tires for city driving vs. track driving, because track use tends to burn through tires. I'm not always "consistent" in following said plan though.
     
  3. mnx

    mnx 2013 P85

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    T/C off. It's pretty aggressive IMO. It's also really annoying to be coming out of a corner and rolling onto the accelerator to have nothing happen until the car is completely straight. You'll have to get used to easing onto the accelerator instead of stabbing it, but it's no big deal. If you get too aggressive stability control will straighten things out in a hurry.
    Plus power oversteer = fun :)
     
  4. Gizmotoy

    Gizmotoy Active Member

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    Unfortunately, the cabin heater is not connected to the battery cooling system in a way that allows it to dissipate battery heat. Given that the motor is directly under the rear seats, and that you can actually see a lot of the electrical components if you pull them out, I've wondered if you'd see some thermal (and weight) benefit by removing them for track days. As far as I'm aware, though, no one has tried.

    So no more driving around the track sweating to death because your heat is blasting on full to keep your turbocharged monster from overheating. Unfortunately for us, that's preferable to getting a few laps in before having the car reduce output for thermal reasons, which is what currently happens.
     
  5. Dreamin

    Dreamin Member

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    ...when it's a 95 degree day...

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    Yes, makes perfect sense.

    And thanks all for the great advice!
     
  6. Michael2000

    Michael2000 Member

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    Does turning traction control off, also turn off stability control?

    Michael
     
  7. Doug_G

    Doug_G Lead Moderator

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    It's not clear. I've taken the car to the track once, and turned off TC. The stability control did NOT kick in at any point.
     
  8. mnx

    mnx 2013 P85

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    With TC turned off, I def had stability control kick in frequently. It's very obvious, you head a loud clunk (like the sound ABS will make when you stomp on the pedal) and the car will go from slightly sideways to straight as an arrow.

    However on one of my trips to the track I think (my theory) is that I got the brakes hot enough that DSC wasn't nearly as effective. I was able to get the car close to what felt like a 45 degree angle drift. Normally DSC will kick in and straighten out the car long before then.
     
  9. gimp_dad

    gimp_dad Member

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    +1 mnx

    I haven't had my Model S on the track but the TC is incredibly aggressive. Even though this car is a performance sedan, it is clearly still intended for mainstream drivers. The hesitation while apexing a turn really ruins the experience. I wish it had two or three modes rather than just on or off. It would be nice to have much more over steer without completely turning off the safety measure. But I guess your point is that stability control will still intervene if you get too sideways...
     
  10. brianman

    brianman Burrito Founder

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    Is this behavior known to be Traction Control? It was my suspicion this was the case but I wasn't certain.

    I think I want most of what T/C offers but this particular aspect I would love to be able to disable.
     
  11. Gizmotoy

    Gizmotoy Active Member

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    In a traditional sense, traction control's sole duty is to prevent the wheels from spinning. Stability control is meant to prevent the car from spinning (or otherwise sliding out of control). I don't have track experience in an S yet, but requiring the car to be pointed forward before unleashing the power typically falls under traction control.

    I do know I'll miss my current car's active yaw control, which is a blast. You can turn all the other nannies off, but leave the yaw control on. Throw it into a corner, slam the throttle to the floor, and slide through the turn with something like a 20-30* slip angle that you don't have to do anything to maintain. Intoxicating. Probably hard to do without AWD, though.

    What's disappointing on the S is that even if you turn off the TC, you still can't disable the stability control. Sounds like it's relatively non-intrusive once the TC's disabled, though, which is good.
     
  12. mnx

    mnx 2013 P85

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    I wonder if Tesla could add active yaw control via a software update. Would the necessary sensors be present?

     
  13. Gizmotoy

    Gizmotoy Active Member

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    It's typically just a (pair of) accelerometer(s), which while being relatively new to cars, are in pretty much every electronic device now and are cheap. I wouldn't be terribly surprised if the existing stability control system had one already.

    For it to work, though, it needs to be able to direct power to certain wheels. Lets for now forget that the front wheels aren't driven. Given the single motor on the S, I'm not sure our rear drivetrain has the necessary active differential for that. I see posts saying we have an open differential where limited-slip is simulated by applying the brakes to the wheels. While perfectly suitable for preventing spins and slides, I do not think such a system would be terribly effective in maintaining a slip angle. Perhaps when the AWD S launches.
     
  14. Dreamin

    Dreamin Member

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    Yes, it appears Tesla has combined Traction Control and Stability Control into one On/Off Setting. While other high-performance cars keep these separate. I'd guess these could be separated in future software.

    And I'd say the car has 'yaw control' functionality, it's just very conservative. Meaning with TC Off, you can hang the rear out much further than with it on. But it really cuts the power once you hit that limit... instead of leaving you just enough power to take the turn at the limits of the tires, or power-slide through the turn. And this is a lot more complicated to do than the 'really cut the power' method - and as Gizmotoy posted, the car may not have the right hardware to implement this.
     
  15. Doug_G

    Doug_G Lead Moderator

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    Curious, I did not have that happen. Mind you, I was babying the car a little bit; I didn't want to bend my 21" rims with an off-track excursion. But I did have the back kick out once without any apparent interference from stability control. I corrected it with steering input and continued.

    If TC were on it would have been an entirely different story. That would have totally got in the way.
     
  16. mnx

    mnx 2013 P85

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    The only differences I can think of are a) I was driving like a maniac. (and had zero training at the time, therefore I was pushing the car pretty hard ie. not driving smoothly and b) I have 19's/goodyears...

    I've had the DSC kick on while driving on the road as well... With the TC off if you punch it and the roads are slippery, the back end will come out for a a very short amount of time before you'll hear the ABS chattering and the car straighten out.

     
  17. Doug_G

    Doug_G Lead Moderator

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    That could be it. I'm certainly no expert driver, but I've been getting a lot of track driving experience in the last few years. Kinda got addicted somehow. I've been called "very smooth" by one instructor.
     

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