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What do you think the ACTUAL improvement of torque sleep will be for the P85D?

Discussion in 'Model S: Driving Dynamics' started by tcampos, Jan 14, 2015.

  1. tcampos

    tcampos Member

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    What do you think the actual improvement of torque sleep will be for the P85D when it is released?

    A bit of context on this question - My P85D is my second Tesla. The first was an early model 85. For the 2 years I had my 85, my lifetime driving average was 348Wh/mi after 20k miles. My driving was a mix of city and highway driving, with probably 65% of the miles in the city, and 35% on the freeway. When taking long trips (e.g. the south peninsula bay area to Napa, or from Mountain View to Monterrey), my Wh/mi would average closer to 325. Overall, my 85 gave me little range anxiety and I had little trouble planning and executing long trips with the car.

    Since getting my P85D last month, I have averaged 398Wh/mile with the same driving patterns. I have noticed that highway driving is not very good, and my Wh/mi there can range from 350 to 410 depending on if I'm going 60 or 75+mph. I don't find my driving to be any more aggressive than it was in my old 85 and I don't regularly do launches in Insane mode.

    Since getting my P85D I have been trying to think through why the car is so much less efficient. My old 85 had 19" wheels, and wasn't a performance version. However the wheels should only account for 3% according to Tesla's website. My car has 700 miles on it so I'm mostly through the 1000 mile 5% tax for new tires. And of course we don't have torque sleep yet.

    So, how much will torque sleep actually provide, and how will that vary under highway vs city driving conditions? I've wondered how much the front and rear motors end up competing with each other in actual driving - particularly at cruise. In a hypothetical wholly inefficient calibration model, one could envision a scenario where one motor is fully providing power, while the other is fully regenerating. In that case, you'll lose a lot of power simply to heat as you transfer power to mechanical energy and back to electrical power through the motor. In a fully efficient model, the two motors are optimally calibrated and share workload perfectly. Torque sleep seems like it would enable this by shutting down one motor entirely, and assuming there is minimal cost in terms of the drag the motor would generate, would return the car to efficiency levels similar to a single motor car.

    However, what about city driving where there is a lot of acceleration/deceleration? Will torque sleep make a difference here? Is it possible that Tesla could release a more optimal algorithm for balancing workload between the two motors? In fact in this scenario, why would there be so much inefficiency between the AWD and RWD models? Wouldn't power be shared efficiently upon acceleration? Wouldn't regen always favor the AWD because you have two motors doing the work and therefore have even less need to use the brakes?

    Most importantly - what will our Wh/mile improvement actually be? Tesla says 10% - for my driving that would get me to 358Wh/m. But will we actually see that much? Might we see more? or should we expect less? What do you think?
     
  2. LetsGoFast

    LetsGoFast Active Member

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    I think it is quite likely that the numbers provided in the blog post were based on real data from a beta version of the software, so I'd expect the predictions to be pretty accurate.
     
  3. tcampos

    tcampos Member

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    I'm less optimistic than you, but I do hope you are right. I'm guessing that my driving style will get to 370 Wh/m and the biggest win will be on the freeway dropping it to 325 Wh/m. Both both numbers are total wild guesses.
     
  4. PunchIT

    PunchIT Member

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    During the P85D launch event, Elon said that the new cars will be more efficient because of the dual motor system. JB, in his blog post said after the torque sleep software update the new cars will be able to match the efficiency of the P85+ despite the dual motor system.

    My head is spinning!!
     
  5. randompersonx

    randompersonx Member

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    I doubt city driving will be improved much if at all. Highway cruise is where the difference will appear.

    That said, Highway cruise is where the difference is needed. If you drive reasonably around the city, range really is fine. I highly doubt anyone needs more city range in one day than the P85D can currently do without any improvements.
     
  6. mastaace

    mastaace Member

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    I am hoping that the future update with torque sleep improves the efficiency as JB mentioned. I have had my P85D for 3 days now, driving 140 miles per day for my commute in a temps 4 to 25 degrees F. I am taking about a 30% range hit driving about 70 to 80 mph on the highway which is not terrible given the cold. This is my first Tesla so I don't know what the range hit is on a P85+ in these conditions.
     
  7. sandpiper

    sandpiper Active Member

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    This ^^

    There was enough data in the blog post to show that it was clearly based on testing.
     
  8. ArtInCT

    ArtInCT Always Learning

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    #8 ArtInCT, Jan 15, 2015
    Last edited: Jan 15, 2015
    I feel that the Highway speed Wh/mi and the City Wh/mi will differ in the their respective percentage increases in Wh/mi.

    Optimally one would want the 65 MPH range to be in the sweet spot in the increase bell curve. If that is the 10% increase speed then one can assume a distance WH/mi consumption rate to be about 355-365 which would result in a vehicle range of 190 to 185 miles based on a 90% charge. Environmentals and altitude +/- would modify those estimates.

    However, it is hard to perhaps drive a P85D with the bias in driving style leaning towards light consumption of WH/mi. Just stand on the accelerator a few times just because the car can, and well so goes some miles of range.

    Maybe the NORMAL mode, if such a third mode will be implemented, would "dampen" the performance of the P85D and try to keep the car in an "85" set of performance parameters. So will the new software provide a third mode? I think there should be a slider with 10 being full 155MPH performance down to 1 being Range bias. These settings, from 1 to 10 would simply limit the top end performance, coupled with Torque Sleep. The accelerator pedal being the actual performance selector with the settings from 1 to 10 defining the upper limit.

    How about paddle shifters to go up and down the performance settings coupled with color around the center circle of the pod, when you are in 10 the circle is bright orange and when in 1 light green with variances in between. Sweet.
     
  9. Todd Burch

    Todd Burch Electron Pilot

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    I'm surprised the OP gets better mileage on the highway. That is unusual...typically people get better EV energy efficiency in city driving.
     
  10. NOLA_Mike

    NOLA_Mike Active Member

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    While I agree that Elon said the Dual Motor will be more efficient than the Single Motor I will personally be thrilled if they can just match what I had before. I could achieve better than Rated Miles in my P85+ with conservative highway driving (60 - 65 MPH in temperate weather and flat terrain would get me 280-290 Wh/mi consumption).

    Based on Tesla's (JB's) statements, I am optimistic that Torque Sleep software will get me close to what I had in the P85+. Those of us that live in the vast Supercharger wastelands are probably more aware of range anxiety than those that routinely drive where Superchargers are spaced every 120 miles or so.

    Mike
     
  11. JerryNycom

    JerryNycom Member

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    I get much better mileage on the highway as well.....
     
  12. 3mp_kwh

    3mp_kwh Member

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    #12 3mp_kwh, Jan 16, 2015
    Last edited: Jan 16, 2015
    Of all the technical info released on the new Volt this week, there are 5 clutches serving to idle that which is not providing drive (2 electric motors, as well, BTW). In so far as Tesla isn't clutching out one of its two motors, I don't think there is much argument software can make up for the mass that stays clutched in. I'd almost bet that, with more scale, they may figure out a means to decouple the motor they chose to idle, from its two half-shafts.

    I bet maybe P85D range can equal P85+ range, but that there's no way P85D will excel around town (where it wasn't claimed to, and won't matter to those paying <$.20-40/kwh). Newton's third law "object stays at rest, or in motion, unless a force is acted upon it" is another way to look at it. It's one thing to add mass to a car, and suffer inefficiency, but doing it within the driveline, itself, makes for an even bigger penalty. F=MA, and AWD owners have more 'M' in the rotating bits, whether or not both of those motors are driving the car. Even when they do, any miss-match whatsoever, comes at an efficiency price.

    P85D did a great job harvesting so much range, given what it can do everywhere else.
     
  13. tcampos

    tcampos Member

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    Well, I've had torque sleep for 325 miles now so it is probably long enough to draw some conclusions. I reset one of my trip odometers after the upgrade and can now say what exactly I'm getting.

    I was pretty close to my estimate. So far, from 325 miles, I'm averaging now 374Wh/m with my driving style. AND, on the freeway at 70mph I'm getting just about 325 Wh/m. If I go down to 65 mph, I can get closer to 300 Wh/m or less depending on how hilly it is.

    Torque sleep seems to really suck if there is any kind of incline or traffic. It just doesn't hold or kick in and you quickly revert to crappy mileage. The best comparison for me of this is in the Bay Area comparing 280 to Hwy 101. on 101 over 50 miles, I'll average 300 Wh/m. Where as for 280 I'll average 410 Wh/m for the same speed. Distance is the same, and net elevation is the same, but 280 has lots of elevation change, while 101 is flat.

    Anyway, given that I was at 398 Wh/m before and I'm now at 374 Wh/m, my efficiency gain thanks to torque sleep is 7.1%, less than the 10% advertised. It is better for freeway driving though, so I guess I'll give Tesla credit where it is due.

    Note: I'm still on .139 and have not received .140 yet though have heard on this forum that .140 performs even better than .139
     
  14. tcampos

    tcampos Member

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    Well, I have to revise my feedback. I did a couple of long highway trips recently with my P85D, and got pretty good range figures that are worth mentioning. The two trips were from the south bay, CA to Modesto, CA and another from the south bay to Napa, CA. The first was relatively flat with two large ridges. The second was more up and down. On the first, I averaged about 74 mph, and got 340 Wh/m for the whole trip over 190 miles. The second did even better, with 335 Wh/m over 200 miles with an average speed of 70mph.

    My post .139 lifetime efficiency over 1,000 miles is now 355 Wh/m which is really close to my previous Classic S85's 348 Wh/m. This is pretty good considering that my S85 had 19" wheels, while my P85D has 21" wheels.

    So, I have to give it to Tesla that they have beat my range expectations. Happy to see it.
     
  15. anxman

    anxman Member

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    Using TACC, I've gotten as low as 255Wh/Mi on 101N but more like 340Wh/Mi on 280N.
     
  16. billarnett

    billarnett Member

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    Are you sure that's not because the traffic is generally faster on 280?
     
  17. anxman

    anxman Member

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    I use TACC set to the same speed for both but I believe that I encounter more traffic on 101. Your theory could be right as i probably have a lower average speed.
     
  18. anxman

    anxman Member

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    Update: On .179, I'm seeing an improvement in efficiency. Using TACC set to 74mph, I achieved 285Wh/Mi yesterday on 280N. Previous low was 340Wh/Mi. Had hit a bit of traffic on a few stretches but overall was traveling at the set speed for probably 70% of it. Hoping that this is consistent. Once I have more data points, I'll update further.
     
  19. fadkar

    fadkar Member

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    I'm glad to hear that the updates have increased efficiency for the P85D.
     

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