For what it's worth, remember that both MarcG and I had a significantly lower SoC when we met up, relative to thimel's measurements.
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Performance of P85D with Ludicrous upgrade review
- Thread starter thimel
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- Driving Dynamics Model S
Nope, the P85D is faster. I took the last quarter mile run from each of tests so they were at similar states of charge. The times to go from 90-120 were 6.92, 6.74, and 6.36 seconds for before upgrade, after upgrade without max battery power and after upgrade with max battery power.
You reported .42 quicker quarter, @11.4
Versus P85D, you reported:
-nothing 0-30
-.3 sec quicker 30-60, from 0
-.5 sec quicker 60-90, from 0
-.56 sec quicker, from times above, 90-120mph, from "the last quater mile run".
Please, reconcile the sum of 1.36 to the .42, because now I'm really confused.
Amazing data and detailed explanation. Thank you!
Here's my question. When Ludicrous update was first announced Tesla said they had a "Smart Fuse" that allowed 1500Amp draw from the battery. With 1500Amp draw * 375V battery voltage (I only know about batteries from my research on EVs online and I'm no engineer but, while drawing high current from the pack, because of sag I don't think it gets 402V)562kW. It is getting 460ish so 460,000/375 = 1220Amps. That is like a loss of 20% converting form DC to AC. I guess it makes sense? This also means 5+ C draw from the pack for a few seconds. Very impressive but again makes it "seem" as if the pack is the limiting factor here rather than the fuse.
Anyone else with better knowledge on this?
Here's my question. When Ludicrous update was first announced Tesla said they had a "Smart Fuse" that allowed 1500Amp draw from the battery. With 1500Amp draw * 375V battery voltage (I only know about batteries from my research on EVs online and I'm no engineer but, while drawing high current from the pack, because of sag I don't think it gets 402V)562kW. It is getting 460ish so 460,000/375 = 1220Amps. That is like a loss of 20% converting form DC to AC. I guess it makes sense? This also means 5+ C draw from the pack for a few seconds. Very impressive but again makes it "seem" as if the pack is the limiting factor here rather than the fuse.
Anyone else with better knowledge on this?
sillydriver
Member
Let me take a shot at this. Time to distance (the quarter) improves slower with more power than time to speed because as your reduce your time to distance you end up achieving a higher trap speed at the end of the distance. Specifically, the 11.82 quarter made it to 112 mph, but the 11.4 quarter required getting to 116 mph in order to make the distance in that short a time. So if the comparison was a time-to-speed 0 - 112 run, the P85DL would have beaten the P85D by a larger time difference. But running the quarter, the P85D was at the end of its race once it reached 112 mph, while the P85DL had to add an additional 4 mph to reach the end of its quarter mile. The time it takes the P85DL to accelerate from 112 - 116 has to be added to the time it takes to go 0-112, making its time-to-distance margin that much smaller than its time to 112 mph speed margin. And while 4 mph doesn't sound like much, at that high speed it probably takes longer to go from 112 to 116 than you think.
In fact if it took 6.36 seconds to go the 30 mph from 90 - 120, then 4 mph out of that is .85 seconds, but since 112 to 116 is in the top part of that range it should take even more than .85 seconds: probably the 1.36 - .42 = .94 seconds you want to explain.
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I agree with both of you. I probably shouldn't have raised the conspiracy theory because I do think it's a crazy idea, as I said. The point that I should have stated better is that it would not be a huge surprise if there is a future software boost for the P90DL that the P85DL is not capable of benefiting from. However, I think the upgrade is good to get even if the P90DL will outperform by more later on. What I care about is increasing the passing power of the P85DL, not how it compares with the P90DL.
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lolachampcar
Well-Known Member
I took a very quick look at Sorka's data and trying to integrate power with the added wind drag element did not tell me much. To be useful, actual battery power draw will need to be examined instead of horsepower required to accelerate the car (which includes variable with speed wind drag).
In case this was a technical question (as well as a request)...
The answer is yes if that shore power is a supercharger.
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Perhaps I missed it but...
Do we have any direct data or preliminary conclusions about whether the acceleration limiter for track use will (a) arrive later or (b) remain at 240 kW (instead of dropping to 160 kW) longer?
Put another way, do we think the fancy fuses will unlock more "non limited" time for the driver or is another component (pack, driveunits, etc.) the root issue?
I guess what I'm asking is:
For a 20 minute lapping session (speeds ranging from 10mph to 140mph), does the Ludicrous upgrade for P85D provide much value?
Got it. So, if the race were to 120mph, rather than the quarter mile that showed up at 112 and 116mph, the P85D would probably have banked that much more time on the P85D (the ~.94sec). Thanks. I topped a much lesser car out in college, on the way to Daytona beach once. So, I know how slow those last few mph come, and that I'm beyond the statute of limitations :tongue: . The only tricky part, now, is the .8 (.3 + .5) seconds that P85D banked to 90mph, before it crossed the quarter line. What happens to those ~4 tenths, if we know the P85D has no disadvantage above 90mph?
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Yes, you can heat the battery on shore power. It consumes about 6kW, so if you have a 40 amp circuit and hence 30 amp maximum charge current, you will need to wait until your charging is complete, leave the car plugged in and then turn on max battery power. It will tell you how long it will take for it to be ready. That time presumably depends on the present temperature of the battery.
Andyw2100
Well-Known Member
We've discussed this in a couple of other threads.
Personally, I would urge caution if considering using the Max Battery Power option to preheat the pack for purposes of eliminating the regenerative braking limitation, or to just generally heat the pack. Tesla has warned against using the option too frequently, with the possible consequence being battery degradation. The Max Battery Power option will heat the pack beyond where you would want it for any other reason, so you'd want to stop it before it completed. Also we don't know if the method used to heat the pack may be different (harder on the pack) than the standard way the pack is heated.
Heating the pack this way would be a work-around, and in my opinion a potentially risky one. Tesla should just give us a pack preheating option. I've started a couple of threads related to that, and have written to Tesla. Now that they are providing the option for performance reasons, perhaps they will also provide it for more practical ones.
You can. See my earlier reply in this thread. Now we just need an API to turn on max battery.
Where has Tesla stated that the max battery option can lead to early degradation?
Nothing happened to the 4 tenths.
Let me try it a slightly different way:
Time to speed of 90 MPH has a 0.634 second difference. I made the mistake earlier of asking why the heck wasn't that time even larger at the 1/4 mile and then I realized my mistake.
The time to 600 feet on thimel's P85DL was 6.95 which was only 0.33 (time to distance) slower than mine. His distance was 600 feet at this time. However, it took 0.634 (time to speed) seconds longer for me to reach the same speed of 93.95 MPH that his had at 600 feet. By the time mine hit that speed, it was *WAY* beyond 600 feet.
| 0-90 | 600 feet | |
| sorka P85D | 7.07 | 7.28 |
| thimel P85DL | 6.41 | 6.95 |
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Cool stuff. When I use online calculators like:
http://www.wallaceracing.com/Calculate HP For Speed.php
The results match your chart nearly perfectly assuming 2.5 square meter frontal area.
It's not a big enough difference to really change the conclusions but it's big enough to make me wonder. I wonder if the drivetrain inertial is a factor here since the calculator and your chart are what is needed to *hold* each of these speeds (static) in which case drivetrain inertia won't come into play at all vs decelerating the drivetrain mass (dynamic).
I think I'll need to pick a speed on flat level ground and hold it with cruise and measure the average KW usage to hold that speed.
jpet
Jan P.
This I am very interested in because I'm afraid the extra heat from the extra power might cause the limiter to appear sooner in a Ludicrous upgraded P85D. If this is the case, the Ludicrous upgrade is not for me. I would just love to be able to get my hands on a P85D to test this. On a track a P85D is not really faster than a P85 because of the 240 kW limit.
sillydriver
Member
It's the same thing. The "no disadvantage above 90" is a time-to-speed measure from 90 - 120, where we are using 120 as a proxy for speed at the end of the quarter. But the two cars have different speeds at the end of the quarter: 112 and 116. The DL takes .8 seconds less than the D to get to 90, but once it's at 90 it has to go from 90 - 116 to finish the quarter mile, while the P85D only has to go from 90 - 112. It takes about .4 seconds more for the DL to go 90 - 116 than it takes for the D to go from 90 - 112, but that's because the DL has considerably more work to do to get to 116. If both cars ran 90 - 120, the DL would take .56 seconds less (not more) time than the D.
Another way to look at it is that the faster car in a drag race hits 90 mph when it is less far down the track. That means it has to go a longer distance after that point to finish the quarter mile than does the slower car after it reaches that same 90 mph speed. Having to travel that longer distance shaves off some of the time advantage it built up by getting to 90 quicker. To see it in the limiting case, say the P85DL races a really slow car that finishes the quarter at only 90 mph. The DL will obviously do 0 - 90 much, much faster, but when the slow car finally hits 90 it is at the end of the quarter mile and it takes zero more time for it to finish the race. On the other hand, the DL is less than half way down the track! I say that because the 1/8 mile trap speed for the DL was almost 95 mph, so it reaches 90 well before it travels half the distance to the goal. So the time for the slow car from 90mph to the end of the race is zero, but is over 4.2 seconds (the difference between 1/4 mile and 1/8 mile times) for the faster DL. So the huge difference in 0 - 90 mph time is whittled back by over 4.2 seconds to produce the smaller difference in quarter mile times. Time-to-speed and time-to-distance are really two different animals.
By the way, that's why the 10.9 quarter for the Motortrend P90DL is so amazing because the half second difference between that and the 11.4 for the P85DL translates into a much bigger difference when it comes to time-to-speed. A 10.9 second car is putting out considerably more power than an 11.4 second car: a bigger difference than you would think from the difference in quarter mile times.
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Andyw2100
Well-Known Member
If my memory is accurate it is in the release notes associated with Max Battery Power, or the information available when you enable it. I'll search and see if I can find something to support that.
Eh, you don't have to know math - you just have to know nice people who know math.
I had this expectation as well, but I don't recall Tesla stating it. Do you have a reference for the Tesla commentary? Was it in the release notes?
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I disagree. My personal experience is that the limiter arrives later on P85D than P85. Also the first limiter on the P85 is 160 kW vs. 240 kW on the P85D. That makes for a nice improvement on the P85D as well.
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Max Battery Power setting in P90DL
"... extra energy consumption and earlier power fade on long aggressive drives."
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