Stop the Press! Tesla announces REAL HP numbers for P85D and P90L

[brianman]

That may just be his choice of wording. If the pack power can be increased beyond Ludicrous, I see no indication that more power won't be available (at least in the range before the back EMF makes it drop).

Sorry, I still don't get it. If the vehicle is not traction limited, motor limited, or "power pack limited" then what is the limiting factor?

 

[lolachampcar]

We know from data (thank you Sorka and friends) that the P90D and P90DL are both pack power limited; it is just that the improved contactor and fuses allow for an increase in that pack limit. Now if you are pointing out that at no time do we ever see a combined 691 hp from the motors as installed in the system, I get why you are asking.

 

[brianman]

We know from data (thank you Sorka and friends) that the P90D and P90DL are both pack power limited; it is just that the improved contactor and fuses allow for an increase in that pack limit. Now if you are pointing out that at no time do we ever see a combined 691 hp from the motors as installed in the system, I get why you are asking.

I'm asking why Elon's phrasing "not power-pack limited" after "Ludicrous upgrade applied" doesn't appear to mean exactly that. How is that not a problem for Tesla?

 

[Andyw2100]

Musk said Ludicrous was tire traction limited 0-30, he did not say P85D was tire traction limited to 30mph. He may also be referring to the region (he didn't name a specific mph, but 0-30, which is a common metric). I looked at sorka's graphs previously and it was traction limited up to 10-15mph (when it reaches peak torque/acceleration). By 30mph, the torque is already well past the peak point. It is not possible to hit peak torque/acceleration if the car is traction limited.

He is comparing Ludicrous to Insane. He is saying that the new fuse and contactors allow the additional acceleration beyond the point the modes have been traction limited in the past. Listen to the audio I referenced above (and below, for your convenience) from about 20.57:

Elon Musk announces Ludicrous Mode for Model S (7.17.15) AUDIO - YouTube

 

[rns-e]

In Nissan case, the issue was power at motor shaft, same as it is in Tesla case. Power difference is extra loads put on the engine (including the auto transmission) made it so the measurements obtained by the plaintiffs had lower numbers than the homologation standard Nissan used, even though they did calculate assuming power at motor shaft. Again, even though the plaintiffs used a wheel dyno, they back calculated to eliminate drivetrain losses to get the shaft numbers, so it was motor shaft vs motor shaft.

In Tesla's case, the power difference will be because the homologation standard does not factor in battery (as well as a couple other loads: Air compressor for brakes; Power steering compressor; Suspension system compressor; Air conditioner system, etc.). If you use a wheel dyno, it obviously does.

I would still say it is two completely different cases as you know that the Nissans whp will be within a reasonable level of the motorshaft power, whereas with the Tesla it will be a completely black box to what you will be getting at the wheel. It may be a loop hole in the technical requirement, but it will not pass the marketing laws as allowing selling goods to customers with central specifications being black boxed would undermine the trust in the whole system.

 

[stopcrazypp]

Sorry, I still don't get it. If the vehicle is not traction limited, motor limited, or "power pack limited" then what is the limiting factor?

The vehicle is still pack limited, just Elon may not be using as accurate terminology. As you pointed out, technically it should be less power pack limited, but still power pack limited.

The ECE R85 tests shows there is extra room in the combined power of the front and rear drive units. By the time the car hits peak power it is already well past the traction limit (whichever limit you want to use 10-15mph as the data shows or 0-30mph as Elon says).

 

[Andyw2100]

My key point being his language doesn't say "less power-pack limited" but rather "not... power-pack limited".

I'm asking why Elon's phrasing "not power-pack limited" after "Ludicrous upgrade applied" doesn't appear to mean exactly that. How is that not a problem for Tesla?

I think this comes down to the fact that at the time Musk made the statements in question, Tesla was not yet admitting that the vehicles' HP was, in fact, battery limited.

So I think you are correct that in light of the fact that Tesla has now acknowledged that, Musk's statements at that time were, shall we say, less than 100% accurate.

I believe that is your point.

 

[stopcrazypp]

I think this comes down to the fact that at the time Musk made the statements in question, Tesla was not yet admitting that the vehicles' HP was, in fact, battery limited.

So I think you are correct that in light of the fact that Tesla has now acknowledged that, Musk's statements at that time were, shall we say, less than 100% accurate.

I believe that is your point.

I don't think that makes sense. That statement Musk makes says that the car was battery limited. Brian's dispute was over if after the Ludicrous upgrade does the car remain battery limited. I think the consensus is that it is still battery limited (from the people who have been looking at P90DL performance), so Elon's wording was not accurate.

If you parse every word Elon says in every single interview/presentation, I doubt every single line is 100% accurate. I made a similar point before. However, I don't think that is material as I doubt anyone scrutinized those words (in this case a single missing modifier is enough to change the meaning) when they made their order. What is on the web page is far more important.

 

[lolachampcar]

Have we not been parsing every little word in Tesla's documentation to justify, accept, allow, etc. Tesla's use of "691 combine motor hp"? It seems this thread is all about parsing.

 

[stopcrazypp]

Have we not been parsing every little word in Tesla's documentation to justify, accept, allow, etc. Tesla's use of "691 combine motor hp"? It seems this thread is all about parsing.

Yes, documentation, but there is a order of magnitude of difference between that and spoken word. No doubt you can hold Tesla liable for documentation (which is what this whole dispute is about), but not necessarily all the words Elon has ever said.

 

[FlasherZ]

I've been trying to follow this thread, but it wanders far too much and I don't get the point of 5 pages or more per day...

I'm not invested in it because I have a SP85 in the garage and an XP90DL on the way. From my perspective, it looks something like this:

Some people complained that the real-world times exhibited do not line up with Tesla's originally-stated performance numbers. Tesla explained how it determined the original performance numbers and, while the explanation shows that the numbers are founded in some reality (e.g., using motor HP but not accounting for power delivery limitations), many (or most) people find that Tesla took some liberties that it shouldn't have with the numbers. Tesla updated the numbers, then, to reflect what many people thought was more realistic. In the meantime, some owners claim that they purchased the car not based on the test drive experience, but rather on the published specifications alone, except that their expectations of the performance number derivation were different. Some of those owners are now expecting Tesla to give them compensation - with the consensus being a for-cost marketed option for free - to make up the difference between the way Tesla derived its performance numbers and the way they expected Tesla to derive its performance numbers.

Did I get that right?

If so, why does this thread continue? Why don't we allow those owners to work it out with Tesla and either a) be satisfied with any resolution, or b) be unsatisfied and follow the processes they feel they need to follow to gain resolution (sell it, sue, or just grin and bear and never buy from Tesla again)?

 

[lolachampcar]

I continue to participate because of a feeling that Tesla headed off in a direction I would prefer it not follow. I also participate to provide a balance to those that try to justify the 691 practice. It seems all to often that history is written by those that post the most words as often as possible. They may have a point but I do not believe it is the whole story.

I have a P85D.
I ordered it before test drives were possible.
I received better than the 0-60 and 1/4 mile times specified by Tesla. (I'm in the US and thus am accustomed to the 1 foot roll out practice)
I was hopeful of doing a once every three years performance upgrade and am disappointed that I have to find my way through the P85D to L upgrade versus P90DL (with its associated ongoing 10.9 second 1/4 mile problem) quagmire. This disappointment does not rise to the level of dissatisfaction or remotely being upset.
I've come to appreciate how those that bought for the first time could be upset if they relied heavily on Tesla's claim of having 700ish horsepower in the P85D.

 

[FlasherZ]

I was hopeful of doing a once every three years performance upgrade and am disappointed that I have to find my way through the P85D to L upgrade versus P90DL (with its associated ongoing 10.9 second 1/4 mile problem) quagmire. This disappointment does not rise to the level of dissatisfaction or remotely being upset.

Thank you for that - that's a point that wasn't coming out for me. Are you saying that you were expecting to be able to upgrade a P85D to a P90DL as a standard offering from Tesla? Or that you were disappointed that the P85D was released, then the P90D with L was released too soon and you would have chosen the latter if you had known about it?

 

[dsm363]

I've been trying to follow this thread, but it wanders far too much and I don't get the point of 5 pages or more per day...

I'm not invested in it because I have a SP85 in the garage and an XP90DL on the way. From my perspective, it looks something like this:

Some people complained that the real-world times exhibited do not line up with Tesla's originally-stated performance numbers. Tesla explained how it determined the original performance numbers and, while the explanation shows that the numbers are founded in some reality (e.g., using motor HP but not accounting for power delivery limitations), many (or most) people find that Tesla took some liberties that it shouldn't have with the numbers. Tesla updated the numbers, then, to reflect what many people thought was more realistic. In the meantime, some owners claim that they purchased the car not based on the test drive experience, but rather on the published specifications alone, except that their expectations of the performance number derivation were different. Some of those owners are now expecting Tesla to give them compensation - with the consensus being a for-cost marketed option for free - to make up the difference between the way Tesla derived its performance numbers and the way they expected Tesla to derive its performance numbers.

Did I get that right?

If so, why does this thread continue? Why don't we allow those owners to work it out with Tesla and either a) be satisfied with any resolution, or b) be unsatisfied and follow the processes they feel they need to follow to gain resolution (sell it, sue, or just grin and bear and never buy from Tesla again)?

You got it right. Agree.

 

[vgrinshpun]

This post is in response to Andy’s polite reminder that I owe explanation of EM remark about traction limitation as related to engineering changes making Ludicrous mode possible.
The transcript of the pertinent question and EM response is included below

Matt, Business Insider (18:57)
Hey Elon. Did you have to make any engineering changes outside battery and electronics on S to accommodate Ludicrous mode? I am thinking about, you know, suspension and chassis adjustments to handle the extra speed. Is that something customers have to deal with if they try to get an upgrade?

Elon Musk (19:21)
No this is just, I mean to get a bit more details on engineering of Ludicrous mode… what it actually enables is for us… car not to be power pack limited past about 30mph. Up about through about 30 miles per hour the car is essentially traction limited. So we just need to put really big wheels on it (garbled, EM seem to be talking about improvement of µ, frictional coefficient of tires) to not be traction limited up to roughly 30 mph
Once you get to about 30 miles per hour the limitation on acceleration becomes how much current you can safely extract from the battery pack. So we currently limit that current to 1,300 amps, but in Ludicrous mode with the advanced smart fuse and Inconel contactor we are able to raise that limit safely to 1500 amps, and so the car is able to continue accelerating at the same, roughly the same rate as it does 0-30 mph all the way pass 60 mph and have improved pack power all the way to max which is electronically limited up to 155 miles per hour.
So if you experienced the insane mode, what it actually means is extension of insane mode pass 30 miles per hour.

So in the above response to the question about engineering changes that enabled Ludicrous mode, Elon is not describing characteristics of P85D Insane, but highlights what steps needed to be taken to achieve improvement in acceleration over and above the Insane mode. In the first part of the response Elon is explaining that increasing acceleration (i.e. increasing slope of the Combined Motor Power –gray line on the power chart below) up to 30 mph is not possible because currently acceleration is maximum that is allowed by traction unless there is really big increase in wheel/tire size (or improvement in tire compound and friction coefficient µ). So rate of acceleration up to approximately 30(+) mph can’t be improved employing reasonable changes.

This leaves the only other way to improve acceleration - raise battery current draw limit to 1500A (green line on the power chart, 532hp according to Ludicrous spec on the web site). Then EM said that rate of acceleration similar to Insane mode is extended beyond 30 mph. According to my calculations, as seen from the chart, the ramp of power along the gray line, up to 31.4mph corresponds to the Insane mode. Ludicrous mode provides further ramp of power along the gray line up to calculated speed of 36 mph.

The sentence that has been discussed and questioned in prvious posts is underlined in the transcript above IMO cannot be true, i.e. Ludicrous does not extend insane mode to 60 mph (according to my calculation it extends it up to 36mph). I believe that EM in his head jumped to a next thought that was about providing boost to 532hp not just for a short interval within the acceleration run, but all the way up to electronically limited speed limit of 155mph. It appears that EM was essentially saying that Ludicrous does not just create a 532hp peak, but extends this power level as a plateau up to the speed limit.

So in conclusion, EM description of “traction limited” meant that “Insane” torque (ramp of power) from 0 speed can’t be increased because the current wheel/tire setup is only able to put the combined 686lb-ft of torque from rear and front drive units to the pavement. Based on the above the improvement in Ludicrous acceleration is due to an increase in power drawn from the battery. Given the context of the question “traction limited” described technical limitation for increasing the combined torque of the motors above the torque produced in Insane mode.

The second chart that is included below is showing the bump in the torque curve that corresponds to the increased battery pwer limit, with incremental area under the torque curve (pink shading) being responsible for the incremental acceleration of Ludicrous as compared to Insane.

The process of constructing the power/torque curves is described here.

 

[FlasherZ]

What I see is that according to Consumer Reports, P85D exceeds 1G within 1/3 of the second after launch, which is roughly just one quarter of time it needs to reach 30mph (1.3sec). Beyond this 1/3 second point, the car is limited by torque, not traction.

What you just posted doesn't answer the question that's being asked. The question that's being asked of you is to explain why the car is limited by torque beyond one-third of a second, as bolded in your quote above.

Did you really mean "beyond this 1.3 second point" instead of "beyond this 1/3 second point"?

Otherwise, you're being asked to explain how one-third of a second applies to traction-limiting -- instead of, as Elon said, 0-30 mph which would be at 1.3 seconds (and not one-third of a second)... was it a typo, or can you explain how one-third of a second applies to Elon's comment about 0-30 mph (which would be 1.3 seconds)?

Yes, I'm being explicit about typing "one-third" (which is what you typed in your quote above and I bolded) instead of "1/3".

(Note: not taking sides but when I read the multi-quote post from Andy here, I saw how this might be a typo instead of an argument over one-third of a second. Just trying to clarify for my own sake.)

 

[stopcrazypp]

What you just posted doesn't answer the question that's being asked. The question that's being asked of you is to explain why the car is limited by torque beyond one-third of a second, as bolded in your quote above.

Did you really mean "beyond this 1.3 second point" instead of "beyond this 1/3 second point"?

Otherwise, you're being asked to explain how one-third of a second applies to traction-limiting -- instead of, as Elon said, 0-30 mph which would be at 1.3 seconds (and not one-third of a second)... was it a typo, or can you explain how one-third of a second applies to Elon's comment about 0-30 mph (which would be 1.3 seconds)?

Yes, I'm being explicit about typing "one-third" (which is what you typed in your quote above and I bolded) instead of "1/3".

(Note: not taking sides but when I read the multi-quote post from Andy here, I saw how this might be a typo instead of an argument over one-third of a second. Just trying to clarify for my own sake.)

See the graphs here and compare to his ideal torque graph. Keep in mind acceleration is directly proportional to wheel torque and that given the car has only one gear, the motor torque has a direct relation to wheel torque also.
http://www.teslamotorsclub.com/show...P90L/page241?p=1269314&viewfull=1#post1269314

Theoretically with no traction limit, the electric motors can immediately output peak torque and the acceleration will be ~1.05 G from launch. However, because of traction limits, it starts from 0 and ramps up instead, as in the graphs I linked. The acceleration/torque plateaus at 10-15mph before it ramps down ~25mph because of the power limit. This is consistent in later tests.

What Ludicrous does in raising the battery power limit is it shifts the torque ramp down point to the left and fills in the pink area in vgrinshpun's graph. Elon is actually correct that it improves acceleration throughout any speed above ~30mph, although not by much (only the pink area, and until back EMF limits things in the highest regions, not accounted for in graph).

The increase in combined motor power from 691 hp (728 hp as per manual makes more sense as vgrinshpun points out) to 762hp also raises the peak acceleration slightly from ~1.05G to ~1.1 G. However, this is supposedly not Ludicrous specific according to the website.

 

[vgrinshpun]

What you just posted doesn't answer the question that's being asked. The question that's being asked of you is to explain why the car is limited by torque beyond one-third of a second, as bolded in your quote above.

Did you really mean "beyond this 1.3 second point" instead of "beyond this 1/3 second point"?

Otherwise, you're being asked to explain how one-third of a second applies to traction-limiting -- instead of, as Elon said, 0-30 mph which would be at 1.3 seconds (and not one-third of a second)... was it a typo, or can you explain how one-third of a second applies to Elon's comment about 0-30 mph (which would be 1.3 seconds)?

Yes, I'm being explicit about typing "one-third" (which is what you typed in your quote above and I bolded) instead of "1/3".

(Note: not taking sides but when I read the multi-quote post from Andy here, I saw how this might be a typo instead of an argument over one-third of a second. Just trying to clarify for my own sake.)

There are two separate issues here.

The discussion started when I pointed to the Consumer Reports Video and graph showing that P85D ramps from zero speed to about 1g in about one third of a second. Various Vbox runs posted on the Forum (I mostly see them posted by Sorka) show that P85D acceleration of about 1g corresponds to the maximum torque available from P85D motors. So based on this data it takes about one third of a second for traction control to ramp torque up to the maximum available from the motors. My original post with the link to Consumer Reports video and snap shot of the chart I am referring to did not make it into Andy's summary up-thread, so I will include them at the end of this post.

The above was disputed by Wk057, Andy, and other posters based on their recollection that Elon during the conference call preceding the Ludicrous unveiling mentioned that P85D is traction limited up to about 30mph. I watched the video back then and concluded that Wk057 and Andy's interpretation was based on taking the traction limiting remark without considering the context. My intention was to make the transcript of the pertinent portion of the call to show that Elon was describing not the limitation of the P85D, but traction limitations in the context of explaining why increasing torque from the motors to achieve further improvement in acceleration was not practical. I did not have time to make the transcript and did not post back then. So this post is catch-up in response to Andy's prompt.

The reason for including charts in my post is to illustrate Elon's explanation of the engineering changes that allowed Ludicrous improvement in performance

Consumer Reports Video is here.

Snap shot of the chart from my original post

- - - Updated - - -

Just to clarify the charts included in my today's post up-thread are for combined motor power of 728hp per the Manual, as construction of the charts requires max power rating and the corresponding rpm for the front and rear motor. As noted by Stopcrazypp above the Ludicrous combined rating of the motors is higher - 762hp. I could not use this value because there is no information on motor speed that corresponds to these motor ratings.

 

[JonG]

There are three things that limit the cars acceleration

- traction
- motor torque
- battery peformance

in a perfect world the cars performance will be the max these things allow.

Comparing insane and ludicrous

traction will be consistent for both
motor torque will be consistent for both
battery performance changes

the question is does the motor torque ever really limit performance? There is so much potential that the battery can't support I suspect not at any speed except possibly standstill.

that leaves traction limit up until the current limit is hit from the battery. If ludicrous can pull more g then insane it is already limited by current.

Maybe it's semantics but isn't the car never torque limited (ie max motor torque which is not the same as max torque delivered by the motors limited by current), it's traction determines the max acceleration which is sustained until the battery limits on current draw kick in which determines when the acceleration drops? If so the envelope is easy - traction limited until the battery can't support it. If not I think it's worth trying to map the three lines, theoetical traction limit (presumably a line representing about 1.1g of acceleration), a torque line representing the motors and how they fail off at speed due to back emf and other properties but assuming they can have unlimited current supply and then the max current draw/power deliverable from the batteries for which ludicrous has a higher envelope. That would show it much more clearly as we can see when each element causes the clip, we can see that with say cold tyres, the traction element comes down but also when it stops being the limit due to other factors, the benefits or allowing peak current to rise further and how that extends the max performance curve.

 

[FlasherZ]

The above was disputed by Wk057, Andy, and other posters based on their recollection that Elon during the conference call preceding the Ludicrous unveiling mentioned that P85D is traction limited up to about 30mph. I watched the video back then and concluded that Wk057 and Andy's interpretation was based on taking the traction limiting remark without considering the context. My intention was to make the transcript of the pertinent portion of the call to show that Elon was describing not the limitation of the P85D, but traction limitations in the context of explaining why increasing torque from the motors to achieve further improvement in acceleration was not practical. I did not have time to make the transcript and did not post back then. So this post is catch-up in response to Andy's prompt.

Ok, I think I understand that.

What that means is that Elon really should have said the car begins being power limited at ~30 mph, not "traction-limited until 30 mph", no?

This is what I understand from what you all have done to educate me in the last few posts:

* The car is traction-limited for the first fraction of a second (to roughly 10 mph),
* The car is then motor torque limited for the next 20 mph or so, until ~30 mph,
* The car is then power limited beyond that.

Do I understand it?

If not, I'll shut up and let the technical discussion continue without my interruption in the interest of understanding how the variables play, but reiterate my concern for any additional parsing of what Tesla says or doesn't say.