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P90D Ludicrous 1/4 mile time

Discussion in 'Model S: Driving Dynamics' started by Burt Reynolds, Oct 10, 2015.

  1. Burt Reynolds

    Burt Reynolds Member

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  2. sorka

    sorka Active Member

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    121.6 MPH is much closer to what I was expecting for 456 KW(I never believed Tesla's 10.9 second claim which I stated repeatedly before anywhere ever got a P90D).

    Is there any chance you can download Powertools onto an iOS device and log the battery power? There are many of us who would like like to see if the power holds steady at 450KW or even increases at higher speeds.

    Nobody has gotten 122 MPH exit speeds yet. Yours is by far the highest. I could believe the vbox might be off my 1mph based on the way tracks measure the end of the 1/4 mile vs the vbox, but not more than that.

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    I'm going to hold my judgement until I see the same run in the other direction. If this was downhill, that could totally make up the difference.
     
  3. DoctorJJ

    DoctorJJ Member

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    P85D's are cutting way better than 1.8 60' times. I believe this car will run a 10.9 with the right battery conditions and right track conditions.
     
  4. sorka

    sorka Active Member

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    Sure hope you're right, but nobody has seen a max power reading of more than 456KW from the battery even when max power says it's "ready". It's going to need at least another 15% more than that to get from 11.3 down to 10.9
     
  5. DoctorJJ

    DoctorJJ Member

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    If he could cut a 1.6 60', (which lots of P85D's have done) that would shave 2 tenths off of his time. That puts him at 11.0 right there. 1 tenth could be air density, tire pressure, or any number of things.
     
  6. P85DEE

    P85DEE Active Member

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    Encouraging to see this result.

    Typcally for street cars, every 0.15 second improvement in the 60ft time, at least 0.1-0.15 seconds of improvement can be expected in the quarter mile ET.

    Is the 1.8 seconds displayed rounded either up or down? I also watched the other YouTube videos for this car and the trap speeds seem to vary quite widely. But nonetheless, 121.6 mph is impressive.

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    Oops. That should have been every 0.1 second improvement in 60, typically gives 0.1 -0.15 second improvement in quarter mile ET
     
  7. fiksegts

    fiksegts Active Member

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    do you have an external antenna on the VBOX?
     
  8. Burt Reynolds

    Burt Reynolds Member

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    The downhill gradient on this segment of road is 1.5-2.0% (I'm a competitive bicycle racer, and thanks to the Garmin GPS that is on my bicycle, and Strava, I know the gradients of the roads in my area uncomfortably well).

    I'm certain that the uphill time and velocity will suffer significantly. I'll endeavor to duplicate the run tomorrow in the converse direction and report back.

    The car performs admirably when "Ready," but when "Preparing" it is discernibly slower. The car takes on average 15-20 minutes to achieve "Ready" status, but will only tolerate two back-to-back 0-100 mph runs before it drops back to "Preparing." It then takes several minutes to once more achieve "Ready" status. It's not slow when in "Preparing," but it certainly loses a step.

    I do have an external antenna on the Racelogic system.

    I too have observed the disparate times in my 0-100 mph runs, and it addition to gradient variations, a second very meaningful determinate has been the aforementioned issue regarding the duration of "Ready" status. In the second of my back-to-back 0-100 mph runs today (which were separated by the duration necessary to complete a U-turn), the status switched from "Ready" to "Preparing" in the midst of the second (and uphill) run as the car pulled through 50 mph at which point there was a perceptible diminution in acceleration as if the car was suddenly plying through a tarmac coated in a thin layer of molasses.
     
  9. Pete90D

    Pete90D Fan of Red Lights

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    Keep in mind that the Pbox rounds up on the screen so he could have hit 11.11 and still shown 11.2. 0.2s improvement on that is in the 10.9s. Using the software is the only way to know just how low it is.
     
  10. fiksegts

    fiksegts Active Member

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    what software version on your P90DL?
     
  11. Pete90D

    Pete90D Fan of Red Lights

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    Do you have 19" or 21" wheels? pano or solid roof?
     
  12. Burt Reynolds

    Burt Reynolds Member

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    Looks like v6.2 (2.5.46)

    I'll look into Powertools software for an iOS. Is that an App?

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    21 inch wheels. Pano roof. But I removed the back seat and the passenger seat in the interest of weight savings for these runs.

    OK, not really! But it does have the 21 inch wheels and pano roof, but no third row of seating. Driver weight is 175 lbs.
     
  13. P85DEE

    P85DEE Active Member

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    Thanks for the assessment as it is very informative for those of us considering the Ludicrous upgrade for the P85D.

    Very interesting information on the "Ready" and "Preparing" steps. If I am following you correctly here, it seems that you are indicating that it is possible for the car to show that it is "ready", and for that situation to change to "preparing" either prior to, or actually during a time when more power is commanded?

    Sorry for all of the questions, but what exactly is the car doing, while it is "preparing"??? Aside from the obvious increase in power demand, is there anything else which seems to make it go into this preparation mode? Can it be avoided? If anyone knows these answers, thanks.

    In light of what you describe above Burt, it would seem that being able to predict performance outcomes, such as would be needed in say a bracket race, or even a head to head race, would be more difficult. Certainly performance can be difficult to predict in ICE vehicles too, and performance is influenced in ICE vehicles by weather among several other things.

    But I really would like to know what are the things which lead to this "preparation" state, as it seems to at the very least make performance capabilities less predictable, and at worse potentially outright handicap performance from your description above.

    Definitely a little for me to think about here as I have a deposit on Ludicrous like some of the other forum members.

    And again I appreciate your assessment.
     
  14. Burt Reynolds

    Burt Reynolds Member

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    Sorry about the absurdly rotated pictures. I'm not quite certain how to rotate them properly, but if you are willing to rotate your head to the left (or your computer to the right) I will explain the Max Battery Power, which might easily be overlooked by other owners.

    Selecting Ludicrous is the obvious first step. The less obvious second step involves tapping the font beneath the "Sport"/"Ludicrous" toggle that reads "Max Battery Power." It doesn't actually look like something you ought to tap. Upon touching this non-button/font that is actually a button, another screen appears that cautions you that utilizing "Max Battery Power" might diminish your anticipated mileage. You then agree to accept this diminished range, and only then does the car go into the "Preparing" mode. Apparently, the temperature of the battery is optimized during this time. After 15-20 minutes, the screen that has displayed "Preparing" at last extols "Ready!"
     
  15. Pete90D

    Pete90D Fan of Red Lights

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    Glad you didn't :) I asked because I'm 215 and got 2.81, so if you got 2.75s (for example) (Pbox rounding up to 2.8s) then we could make a very broad assumption that 100lb would save 0.1s. That would mean that if the pano is another 100lb+ that it would remove another 0.1s and rotational mass of the 19" wheels might bring it down to 10.9. It is unfortunate that the P85D was able to exceed numbers without nitpicking weight, but might explain how Tesla got the numbers. Temperatures in your area are close to what they were when I was doing my initial testing so it's close there and we might be at different elevations.

    Powertools will get data from the streaming API like kW and timing, but it is captured every 250ms so it isn't super accurate. For the pbox files you can either send them to me or sorka to analyze or you can upload them to vBox Verify. That will give exact numbers for your runs.


    Yes it will change back to preparing. I mentioned this in one of my posts when I was testing after delivery and have it as one of my "why I don't use this crap" reasons. From my experience using the option it takes a variable amount of time to be ready, however it seems that building up heat through launches will speed it up. When I hit 2.81s I didn't have the option enabled, and so far I haven't beat that time with or without it on. After launching several times it will cut off on you from what I believe it heat from the battery because you'll hear the cooling going crazy. AFAICT the only thing it does is warm the battery to an optimal temperature, something you can do by launching several times and once the battery starts to get too hot it will go back to preparing while it cools down to the right temperature.

    My personal assessment of the option is that it is beneficial if you want to maximize power earlier in a drive without wasting tons of battery warming the battery. However it doesn't appear to be needed to actually get the performance.
     
  16. Burt Reynolds

    Burt Reynolds Member

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    #16 Burt Reynolds, Oct 10, 2015
    Last edited: Oct 10, 2015
    Completely agree with Pete90D.

    The head-to-head racing could be a touch tricky. And in fact, much of my testing with the car this week has been in preparation for races against my pals and their various non-EVs.

    To get the car "Ready!" you can do everything reported by Pete90D. Another option is to turn the car "on" while it's sitting in your garage, go through the semi-silly sequence of enabling the "Preparing" mode, and while leaving the car to do it's thing, you could go back into your house and eat a sandwich. Once you have finished your sandwich, the car should be "Ready," unless you are a particularly swift consumer of sandwiches.

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    As the car is only good for 2 or 3 really hard extended pulls in a row while in "Ready!" mode, I'll plan on coming up with some particularly engaging stall-tactics so as to allow my battery time to regain it's ideal temperature between runs. Showing others the amazing storage capacity of a car that lacks a large combustion engine and accompanying transmission is always good for at least a few minutes of stalling. And this might be extended to 10 minutes if a small selection of sandwiches and beverages is available in the "frunk."

    But in all seriousness, this is a vulnerability of the Ludicrous mode. I know that ICE cars can overheat their engines, clutches, supercharges, etc. But the P90D in Ludicrous mode at Max Battery Power loses significant power after only two or three long runs. I'm pretty sure I'll beat my pal's 2012 911 Turbo in a 0-100 race. And I bet I'll beat him in a roll from 20 mph to 100 mph. But if we race more than twice in a row, I'm going to invite him to help himself to the Sandwich Frunk for a few minutes of stalling, or I'm confident that the dynamics of the race will change markedly on the third run.

    All of my runs were performed at 6000 feet above sea level, which likely makes the car slightly faster due to lower air density. But the lower oxygen content of the air at this altitude would reduce the power of the engine. Kidding!
     
  17. Pete90D

    Pete90D Fan of Red Lights

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    I've made the joke that if I wanted to launch out of my garage at 0-60 the option is perfect. Unfortunately there is a another garage right across from mine so it won't end well :)

    Plus I've driven the car enough now that I'm happy with the day to day performance at various speeds and the data collection is purely for the data nerd in me. Had I paid the $13k extra and not been able to get 2.8s or not had better highway power I would have been a little upset.

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    This was one reason I stopped using the option. I'd rather be able to launch or have high speed power in the "really good" range for longer. I didn't like that the cooling would turn on, it just made me feel like it was being pushed too hard too many times even if it is alright. Warming the battery myself gives me more uses of the power before cooling kicks in, it might not be the max power until it warms, but it's still really amazing. I don't know what the effect of the cooling or overly warm battery will do to the performance in terms of numbers, but it felt a little more sluggish.

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    I'm pretty close to sea level (or a couple hundred feet above) all the time and fiksegts should also be around the elevation I'm at being in Miami. So it's good to know that two factors here are at least 5000ft of elevation and 40lb less weight (in my case)
     
  18. P85DEE

    P85DEE Active Member

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    That was funny.:biggrin:

    But I'm a bit confused so I want to be sure that I follow both you and Pete with regard to the Maximum battery thing.

    To the question; "does one, or does one not, need to select the Maximum Battery Power option in order to get the best results?", it seems that it is not entirely necessary. However if one forgoes this route, well then the car can be made ready, or made to reach a state of readiness, "by launching several times" to warm up the battery pack?

    Is this correct?
     
  19. Pete90D

    Pete90D Fan of Red Lights

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    Based on my experience... you do not need the option on to get best results. However, you do need the battery to be at a minimum temperature, which happens sooner if you enable the option. The same temperature can be achieved by launching, but that will most likely use more battery power.

    Here is the one thing I haven't completely figured out yet. When we charge the cooling kicks, but even when I've left a supercharger it has taken a good bit of time to get into the Ready state. The first time I did it, it took like 2 minutes with no launches, two other times I did it, it took like 10-20 minutes with a launch or two. I would think that supercharging would cause the battery to reach a certain temp, but what it might mean is that the battery is too warm when charging and it needed to cool down. Since "too hot" also resets the status to "Preparing..." it is a possibility.
     
  20. P85DEE

    P85DEE Active Member

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    Thx.

    If you're using the technique of hard launches, and hard driving to warm the battery as opposed to selecting the Max Battery option, how many launches do you need, or how much driving do you have to do before you are at or close to the optimum battery temperature for your best results?

    Also, is there any way to tell when you're just about at that point?
     

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