Performance of P85D with Ludicrous upgrade review

[fiksegts]

great data! P85DL is strong for sure! I might take my P90DL to the drag strip this week and give it a run....

comparing vbox vs vbox is great, but one car on the vbox and another at the dragstrip, not so great...

looks like the cars are close enough that if they were racing each other, who ever got the jump would probably stay ahead....

 

[sorka]

Interesting. On the 451KW run, the slope of power drop off is steeper than the P85D 415KW run. I don't have a 1/4 mile run, so I compared up to 88 MPH.

In my run up to 88 MPH, my rear wheel power starts at 486 at 48 MPH and declines to 419 by the time 88 MPH hits for a drop of 67 hp.

In the 451KW Ludicrous run, the power peaks at 543 at 46 MPH and drops to 446 hp by 88 MPH for a drop of 97 hp.

This slope continues linearly up to the 1/4 mile:

Could this explain why the 1/4 mile time isn't as fast as we'd expect given improvement in the lower speed ranges?

 

[P85DEE]

great data! P85DL is strong for sure! I might take my P90DL to the drag strip this week and give it a run....

comparing vbox vs vbox is great, but one car on the vbox and another at the dragstrip, not so great...

looks like the cars are close enough that if they were racing each other, who ever got the jump would probably stay ahead....

Could not agree more. On both points.

And lest anyone think otherwise, the vbox vs on track results are really just my own musings and thinking that the vbox should at least be close to actual on track results. In other words, based upon the vbox results, I'm expecting quarter mile times in the 11.3-11.4 range for the P85D. Which is what we are seeing in the P90D now.

And thus I arrive at the same conclusion, that it looks like the cars would be close enough that if they were racing each other, whoever got the jump would probably stay ahead over the quarter mile.

But no doubt things such as track prep and over how much of the length of the track, would make a difference in the final quarter mile results for each car, and part of why comparing vbox vs actual on track times is not the best method.

 

[sundoc]

Awesome stuff thimel!! Thanks a bunch for all the great data. And thanks to the rest of you guys who're crunching the numbers further!

 

[CraZ8]

Since the aceleration is traction limited up to 30 mph would some 9 inch or a 9/10 staggered set up with some more aggressive tires make a difference in these times?

 

[kirkbauer]

Since the aceleration is traction limited up to 30 mph would some 9 inch or a 9/10 staggered set up with some more aggressive tires make a difference in these times?

I have really wondered about this for a long time -- I imagine there are some impractical tires that have very high traction and I'd be very curious how those affect 0-60 performance.

 

[ICUDoc]

Quality post, thimel. Good planning, good execution, good write-up. Many, many thanks.
Enjoy the monster in good health, mate.
regards

 

[lolachampcar]

Interesting. On the 451KW run, the slope of power drop off is steeper than the P85D 415KW run. I don't have a 1/4 mile run, so I compared up to 88 MPH.

In my run up to 88 MPH, my rear wheel power starts at 486 at 48 MPH and declines to 419 by the time 88 MPH hits for a drop of 67 hp.

View attachment 102852

In the 451KW Ludicrous run, the power peaks at 543 at 46 MPH and drops to 446 hp by 88 MPH for a drop of 97 hp.

View attachment 102853


This slope continues linearly up to the 1/4 mile:

View attachment 102854

Could this explain why the 1/4 mile time isn't as fast as we'd expect given improvement in the lower speed ranges?

Sorka,
All the work being done here is fantastic and I too am circling back around to thinking Tesla is doing some energy management. It does not appear the function is simple. The data suggests it is more complicated in nature thus a little harder to ferret out. I'll do some manual integration of energy use between your two curves to see if the net energy being extracted is being managed.

Every now and then we get really lucky on this forum. I would love to hear a professional battery nerd chime in with information on how battery pulse delivery is determined and how it is managed to achieve battery longevity goals.

 

[335eye]

Can somebody please boil this down to some practical conclusions? What's worth getting, what's not? Cost benefit analysis? Thanks much.

 

[kennybobby]

The TM site specs page now has a motor torque of 713 ft-lbs, previously it was 687--is that for the P85D, or P90D, or with the L option?

i used the 1/4 mile run graph that sorka posted to calculatus the motor torque using nominal gear ratio and tire size, etc, and it is coming out higher than the spec. Maybe L option does provide for more motor torque?

mph hp rpm torque

10 170 1178 757 ft-lbs
15 250 1768 742
20 325 2357 723
25 388 2947 691
30 440 3536 653
35 490 4126 623
48 539 5658 500

 

[Cottonwood]

I was somewhere between 85-90% and my battery was warm enough max battery did nothing. You can hit optimal temp just driving around. Max battery only helps if you can't do that or if you can do a 0-60 out of your garage

Can you heat up to Max Battery on shore power? That would allow you to have a high SoC and a warm battery. It would also be an interesting work around for starting a winter hypermile adventure with the battery well warmed up; heat the battery with "Max Battery," then turn off Insane/Ludicrous and turn on Range mode.

 

[sillydriver]

thimel -- and other data/analysis contributors -- fantastic work and an excellent thread.

I believe the L upgrade to the P85D is worthwhile at $4500 incremental for those with a deposit.

On the other side, this all makes me feel more confused about the promised 10.9 quarter for P90D owners, the 10.9s MT car, and whether there is a further performance bump through software for either the P90DL or upgraded P85DL. For one thing, when the MT article came out I thought it surely must be a signal that software to deliver the promised performance to P90DL owners was ready for release, since that article would just infuriate those owners otherwise. But a fair amount of time has now passed and nothing has happened.

Then there is Sorka's data that P85DL power falls less than P90DL power with speed. What I infer is that both cars are regulating output to manage the total integrated power (i.e. total energy) in an acceleration run, probably to manage the battery's total heat build-up and temperature. But if both cars are already operating in the regime where they are bumping against thermal limits that need to be managed, then further software to lift these limits seems less likely than if the limit on performance for both cars was just an artificial software restriction imposed for the sake of caution, which could be easily lifted.

Also, the data that the max battery power setting makes a big difference to P85DL performance but not to the P85D makes me think that the P85DL is genuinely limited by impedance in the battery, which is reduced by heating using max power, so it is not limited artificially by a software restriction that can be easily removed.

Of course one other explanation is that the upgraded P85DL is genuinely at its thermal and impedance limits and can improve no further, while the P90DL is still artificially restricted (hence the faster power falloff) where that restriction will ultimately be lifted. That plays into the conspiracy theory that the company wants P85D owners to be suckered into the upgrade first, after which the P90DL will receive a performance jump that would put that car way ahead for good. I have always thought this was a crazy theory (I don't think the company is making much money on the P85D upgrades) but who knows?

So my conclusion (and my advice) is to evaluate the P85DL upgrade using these pessimistic assumptions: 1) that's it -- that is all we are going to get; and 2) there is a real possibility that the P90DL will ultimately be significantly faster. Yet even so, as I said above, my opinion is that the testing in this thread has shown the P85DL upgrade delivers enough of an improvement right now to be a worthwhile purchase.

 

[yo mama]

So my conclusion (and my advice) is to evaluate the P85DL upgrade using these pessimistic assumptions: 1) that's it -- that is all we are going to get; and 2) there is a real possibility that the P90DL will ultimately be significantly faster. Yet even so, as I said above, my opinion is that the testing in this thread has shown the P85DL upgrade delivers enough of an improvement right now to be a worthwhile purchase.

I've never understood the pessimistic speculation that P90D owners might get some kind of diabolically timed software upgrade later once the P85DL upgrades are complete. If something like that were to happen, shouldn't we be happy for the P90D owners? Shouldn't we be grateful that Tesla can and does these sorts of upgrades for their customers, in general?

- - - Updated - - -

Can somebody please boil this down to some practical conclusions? What's worth getting, what's not? Cost benefit analysis? Thanks much.

If you have a P85D, are eligible for the ludicrous upgrade, want to go significantly faster (especially in the 30-60 department, and for freeway passing), and you can reasonably afford $5,000, then the upgrade is totally worth it. If you lease that's adds another dimension but may still be subjectively worth it to you depending on how long you get to enjoy the upgrade and/or whether you plan to buy the car at the end of the term.

 

[3mp_kwh]

Can somebody please boil this down to some practical conclusions? What's worth getting, what's not? Cost benefit analysis? Thanks much.

Assuming your first post is with P85D, in hand:
-About .5-.6 second better 60-85mph passing power, per yo mamma and MarcG data
-Up to .45 second better 60-90mph passing power, per Thimmel's data (possibly bad benchmark, with a cold P85D distorting the gap upward / 3.81 time)
-2.9 vs. 3.1 second 0-60
-Higher, but possibly narrower kw spikes (I think times really supplant need for this info, but useful)
-Possible .2 second, or more, losses from a cold battery, at 50F or lower temps

The promised .2 seconds quarter, from Tesla P85D, were a let down, for most, but I think what I'm reading is that, despite this still possibly being true for the (irrelevant) full 1/4 mile, folks are happy that improvements went where almost everyone wanted them, from somewhere between 31-90mph. Left to be cleared up, is how the .45-.6 second gain, in specific roll-on from constant 59mph, was achieved:

• Slower 91-1/4 mile trap elapsed time?
• and/or proof that the P85D allows grater power output, when not doing an entire 0-1/4 mile run?

The data may bear out one, or the other. Anyone, feel free to true this up.

I'm boiling down from the following:

Model	50-80 mph	60-85 mph
P85D Insane	3.4 seconds	3.3 seconds
P85D Ludicrous	2.9 seconds	2.7 seconds

Thimmel's data showed, for 60-90mph runs, from constant 59mph, with (2) P85D Max warmed up, and (1) P85D possibly not:
3.36, 3.55 and 3.81, respectively.

 

[ERP]

First, I want to say thanks to everyone who is collecting and analyzing this data. But there is something about the OP's data set that bugs me.

The improvement between P85D and P85D for 0-100 mph is a solid 1.0 seconds, 8.8 vs 7.8 (with warmed battery)
But the 1/8 mile improvement is only 0.2 seconds, 7.4 vs 7.2 with low 90's trap speeds.
Then the 1/4 improvement is 0.4 seconds, 11.8 vs 11.4 with low/mid 110's trap speeds.

(The rollout/no rollout issue can be dropped since the comparison is regarding the change in time of similar tests.)

The data above is conflicting. The 0-100 shows a large improvement in total power. The 1/8 and 1/4 mile data shows evenly matched cars with the P85D slowly pulling away. While all the 0-XX mph comparisons shows the P85D adding more and more time with each 10 mph. They can't both be right.

I've never understood the pessimistic speculation that P90D owners might get some kind of diabolically timed software upgrade later once the P85DL upgrades are complete. If something like that were to happen, shouldn't we be happy for the P90D owners?

In this scenario, I think it would be unfortunate that the P90DL owners would be forced to wait.

 

[sorka]

I've been meaning to get around to this for a while and post a coast down in neutral drag/drivetrain loss chart. The problem is it takes a much longer stretch of flat road to coast in neutral than it does when you apply full power to accelerate quickly and then decelerate quickly. The result is I only have it in chunks of ranges.

This is for my P85D from 93 MPH down to 77 MPH in neutral with calm air. It measures the horsepower applied by air resistance, tire drag and deflection, all drivetrain inertial losses and drivetrain frictional losses. The vast majority of the losses come from air friction:

At 93 MPH, it takes 72.5 hp and goes down to 46.5 hp by 77 MPH.

Another one from 63 down to 57(sorry for the hole):

So by the time we get down to 57 MPH, it takes 18 hp to keep that speed vs 72.5 hp to keep 93 MPH.


This accounts for the KW divergence from the horsepower measured at the wheels where you see my previous graph show less power power at the wheels during the 415KW acceleration run as the speed increases.

So if it wasn't for drag, and mainly the drag that changes due to speed(air resistance), the vbox power graph would appear flat. But not so with thimel's. His decreases faster than than drag can explain. I'll have to go back and look closer at his KW plots from Powertools.

Of course to truly accurate about this, I'd have to do exactly the same thing in both directions and then average the data which would take a heck of a lot of work.

- - - Updated - - -

First, I want to say thanks to everyone who is collecting and analyzing this data. But there is something about the OP's data set that bugs me.

The improvement between P85D and P85D for 0-100 mph is a solid 1.0 seconds, 8.8 vs 7.8 (with warmed battery)
But the 1/8 mile improvement is only 0.2 seconds, 7.4 vs 7.2 with low 90's trap speeds.
Then the 1/4 improvement is 0.4 seconds, 11.8 vs 11.4 with low/mid 110's trap speeds.

(The rollout/no rollout issue can be dropped since the comparison is regarding the change in time of similar tests.)

The data above is conflicting. The 0-100 shows a large improvement in total power. The 1/8 and 1/4 mile data shows evenly matched cars with the P85D slowly pulling away. While all the 0-XX mph comparisons shows the P85D adding more and more time with each 10 mph. They can't both be right.




In this scenario, I think it would be unfortunate that the P90DL owners would be forced to wait.

Time to speed vs time to distance are very different things and the time to speed difference will be a lot larger than the time to distance. See my chart using thimel's 451KW run and the time to 600 feet vs time to 90 MPH.

 

[ardart99]

Great Information ...... come on upgrade centers ....

 

[thimel]

Power droop

In my original post, I showed the plot below of the battery power and speed as a function of time both before and after the ludicrous upgrade.

It was a mystery to me why the power peaks at about 4 seconds and then gradually drops and then drops even more rapidly after about 8 seconds. I think I now understand this and it is related to whether there is a finite amount of surge power available. Now, I'm not a battery expert and not at all sure about this, so let me lead you through the thought process that lead to the conclusion.

First hypothesis: Tesla's firmware is purposely reducing the power to the motor to keep something (inverter or motor or battery) from overheating. I doubt this is the case, because even before the upgrade the power droops, so if it was a heat problem, there would be more heating (because of more power) after the upgrade and it would droop faster. Also, 10 seconds is a pretty short time period for a liquid cooled system to significantly change temperature. Typical time constants are minutes.

Second hypothesis: Because of back EMF, a higher voltage is needed to drive current through the motor and there is a maximum voltage the inverter can put out. Again, I doubt this since the droop exists before the upgrade.

Third hypothesis: Tesla is firmware limiting the battery current to protect the fuse and contactors and they increased that limit with the upgrade. Given that the upgrade involved a smart fuse so they could run closer to the fuse limit and higher current contactors, this is very likely. The second part of this hypothesis is that they are applying that maximum current the whole time of my acceleration runs. If that is the case, then the voltage from the battery must be drooping during the acceleration run.

I looked into why that could be. It is a fact that lithium ion polymer batteries used for RC airplanes have both a continuous and pulsed maximum discharge rate. The batteries I have looked at allow a pulsed discharge 50% higher than continuous and allow it for 10 seconds. I had no idea why this was the case, but perhaps it is related to the power droop. So, I googled it and found this paper: https://www.unibw.de/rz/dokumente/getFILE?fid=8968652&fd=kein titled "Utilization of the Battery Recovery Effect in Hybrid and Electric Vehicle Applications" which talks about pulsed power from batteries. In particular, it has a plot shown below of the battery voltage as a function of time when a pulse of power is taken out.

At time -20 seconds in the plot they start drawing a large current. There is an immediate drop in voltage due to the internal resistance of the battery. There is then a more gradual drop in voltage for the next 20 seconds until they quit drawing the large current at time=0. So, according to this plot, the battery voltage does droop when one draws a large current and the timescale is similar to what is seen in my acceleration tests.

The paper goes on to explain the mechanism behind the voltage droop has to do with diffusion of ions through the electrolyte.

Conclusion: In a long acceleration run the power gets reduced over time due to battery physics. So, as lolachampcar suspected, there is a finite "surge" of power available. My test to see if this was the case was to compare the times to go from 30 to 60 mph when starting from 0 and starting from 29. They were virtually identical so I concluded there was no surge. I also compared the times to go from 60-90 when starting from 0 and starting from 59. Again, no significant difference. However, if you look at the first plot, there is only significant droop starting at about 80 seconds and by that time the car is going 80 mph. So, I suspect that if one compared the times to go from 90-120 mph starting from 0 and starting from 89 that the later would be faster. Perhaps someone with access to the German autobahn will test this. I certainly won't be doing so.:smile: For the way most of us normally drive, this droop has no significant effect. For those trying to understand the quarter mile times, it is the reason the hp is slightly reduced in the last part of the quarter mile run.

 

[3mp_kwh]

So, I suspect that if one compared the times to go from 90-120 mph starting from 0 and starting from 89 that the later would be faster. Perhaps someone with access to the German autobahn will test this. I certainly won't be doing so.:smile:

Even in the two data sets we're looking at, yo mamma's 60-85mph runs versus Thimmel's 60-90mph, we're seeing what looks like some time fall-off in those last 5mph (where the .5-.6 gap shrinks to .45). I think this might also support your point. "Surge" is being allocated, whether by physical limits or by the battery management system. The P85D may have a slower 90-120, than the P85D (but what US road driver cares?).

 

[sillydriver]

I've been meaning to get around to this for a while and post a coast down in neutral drag/drivetrain loss chart. The problem is it takes a much longer stretch of flat road to coast in neutral than it does when you apply full power to accelerate quickly and then decelerate quickly. The result is I only have it in chunks of ranges.

Sorka, this data is brilliant!! Once I get off my butt I can fire up Mathematica, figure out the elements of power consumption proportional to v and v^2, estimate the power loss proportional to acceleration (spinning up the tires) and figure out how much power the Motor Trend car needed to hit 122.7 in 10.9s after hitting 100 in 6.9. Thanks.