[updated with *] P85D 691HP should have an asterisk * next to it.. "Up to 691HP"

[p85dk]

If you look at the simple hp figures for the motors of the 85D then the total output added together in the same way as they are adding together the motor outputs of the two P85D motors would be 2 x 257 hp = 514 hp yet they choose to quote the power at 422 hp.
View attachment 84146

So 257 + 257 = 422 hp at Fremont but they will not tell us what 221 + 470 equals using their secret calculator ... 422 is about 18% of the 514 so using the deduction of 18% from 691 gives us 566, which is close to max kW under acceleration which is 418kW. Given those numbers the correct number when advertised would be approx. 560 hp, but wait that is energy into the motors, not out of the motors ... but still more truthful than the 691 hp

@ warpedone 'I'm sure quite some cars were sold on the basis of misunderstanding the 691 HP figure.'

+1

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and the reason no "good" runs have been done is that the Tesla is not geared. So the torque rips the Dyno's apart.
The best you can hope for is some runs with a rolling start to mitigate the torque peak at low rpm.

It is not so much the ripping the dynos apart thing as it is making sure the car stays on the dyno. Due to the instant torque there is a real danger of it leaping off the dyno and crashing into what is in front of it. When I had mine on the dyno and it ripped the timing belt as you all have seen on the video, the main reason we did not have a from zero max power run was that we did not feel sure that it would stay on.

As you all know there is 8 drums in total on a dyno, 2 at each wheel, one front and one rear. The fact that it ripped the belt plays into the fear of it leaping off the dyno, as the reason it ripped the belt was that it 'jump' onto the front drums and for a short moment it did not have contact with both drums and was only spinning the front drums, with its massive torque, leaving it up to the timing belts to make sure the rear drums was rolling at the same speed. One of the timing belts was not up to the task and paid the ultimate price.

So, until there is an owner of a dyno and an owner of a P85D that are willing to risk it leaving the dyno we will not get the full figures - but I do not think they will be much closer to the marketing figures than what we have seen so far.

 

[sorka]

No ICE car ever has a dyno run starting at 0 RPMs so why are people trying it with the P85D? We know that that at 100% SOC that peak power on the P85D doesn't come until about 35 MPH(Looking at over a dozen runs with data collected through REST on my on P85D).

I'm also looking over about 30 dyno runs from tuning sessions with my Zs and Corvettes from about 1995 to 2008. Every single one starts in 4th gear at about 1500 RPMs. To get to that, I start off gently and shift to 4th. Just because the P85D produces enough torque at the very bottom to shred the synchronization belt doesn't mean you need to do that to get valid data if what you want is peak hp.

Sule, in the other forum has been very vocal stating that Dynojets can't measure peak hp on a P85D but this is total rubbish. A Dynojet can measure hp from anything that can turn the drums. It could be a steam engine for all it cares.

å

 

[stopcrazypp]

No ICE car ever has a dyno run starting at 0 RPMs so why are people trying it with the P85D? We know that that at 100% SOC that peak power on the P85D doesn't come until about 35 MPH(Looking at over a dozen runs with data collected through REST on my on P85D).

The big reason there is so much doubt is because so far that the dyno runs for the P85D only measure 430hp, the same as a P85, but REST says power draw is much higher near 550hp. Easing it in may have the computer limit power. Does anyone have the REST API numbers at the same time they are doing the dyno? I doubt the REST was saying 550hp and the wheels are outputting 430hp. 120hp of heat is a lot to remove.

Every single one starts in 4th gear at about 1500 RPMs.

Well the main reason why ICE dynos start at 1xxx RPM is because the engine needs to idle. Any lower and it might stall (esp. in 4th gear). This obviously doesn't apply to EVs.

 

[AWDtsla]

Well the main reason why ICE dynos start at 1xxx RPM is because the engine needs to idle. Any lower and it might stall (esp. in 4th gear). This obviously doesn't apply to EVs.

It won't "stall" until you get under starter rpm, which is very very low:

1. The power output is completely pathetic and not worth dyno'ing
2. Up until very recently (and maybe still) this may actually destroy your engine because of lack of properly ignition timing and fuel mixture in that region of operation. Otherwise known as "lugging". This is why 0-60 times are better than rolling start/5-60 times, you avoid the "pathetic" region of an ICE.

 

[sorka]

It won't "stall" until you get under starter rpm, which is very very low:

1. The power output is completely pathetic and not worth dyno'ing
2. Up until very recently (and maybe still) this may actually destroy your engine because of lack of properly ignition timing and fuel mixture in that region of operation. Otherwise known as "lugging". This is why 0-60 times are better than rolling start/5-60 times, you avoid the "pathetic" region of an ICE.

Yes, but this threads hinges on what the peak power is and whether it makes 691 or not which of course it doesn't. We don't need dynos starting at 0 RPM / 0 MPH in order to produce validating data.

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The big reason there is so much doubt is because so far that the dyno runs for the P85D only measure 430hp, the same as a P85, but REST says power draw is much higher near 550hp. Easing it in may have the computer limit power. Does anyone have the REST API numbers at the same time they are doing the dyno? I doubt the REST was saying 550hp and the wheels are outputting 430hp. 120hp of heat is a lot to remove.


Well the main reason why ICE dynos start at 1xxx RPM is because the engine needs to idle. Any lower and it might stall (esp. in 4th gear). This obviously doesn't apply to EVs.

Yes, but that was at 70% while the P85 runs I've seen that produce 430 are near 100%.

 

[stopcrazypp]

Yes, but that was at 70% while the P85 runs I've seen that produce 430 are near 100%.

428hp around 70-80% (at ~0:45 you can catch a glimpse of the battery bar).
https://www.youtube.com/watch?v=xVmdr5nUArQ

436hp at just 80%:
http://insideevs.com/tesla-model-s-p85-hits-dyno-video/

 

[p85dk]

“Torque is what gets you to the speed you want quickly; horsepower is what keeps you there.” - Charles Hubbard, Lexus College

P85D has massive torque, also compared to the P85, and it has AWD for better traction. But at speed the P85D superiority compared to the P85 or 85D is minimal and nowhere near 691hp or even 550 hp over 430 hp.

The only constant between the P85D, P85 and 85D is the battery and the extra performance in the P85D and 85D is their ability to produce and apply torque better than the P85. So the battery is the limiting part and the hp of the P85D is not much more than the P85 or 85D can produce.

Tesla should just have advertised the P85D as a torque monster rather than pushing the 691 hp, that would have been the most accurate thing to do

 

[thegruf]

okay so need a dyno on a dragstrip then :biggrin:

 

[stopcrazypp]

Someone should do a dyno run at 100% SOC (or close) with the corresponding REST API numbers being pulled at the same time. It'll answer a lot of questions (mainly the big gap between the reported peak REST numbers at 550hp vs measured 430whp by dynos so far).

 

[cassiri]

Is it possible to break all 4 wheels loose at launch if traction control is off? HP aside, with that much torque I would think you could light up 245's for sure. No?

 

[sorka]

Well, since it doesn't happen on the road, I'd say not unless the grate pattern on the drum has worse traction than asphalt.

 

[p85dk]

Well, since it doesn't happen on the road, I'd say not unless the grate pattern on the drum has worse traction than asphalt.

I would guess that the traction is better on dry proper asphalt at the right temperature than on the steel drums. The grooves on the drums are for noise cancellation rather than traction

 

[AGT Tactical]

very interesting, and thank you for this. I myself hope the hardware is fully capable of the advertised 691HP and hope it can be unlocked with a simple OTA update. If the car performs this well with 560HP, imagine how amazing it will be with 691!

@Krisg81: After the hours and hours you've spent on this subject, this never crossed your mind? That perhaps a future update will unleash the car's full potential?

Besides, like the others here, I'm getting nauseated by your endless whining. Every car manufacturer advertises the peak possible engine hp, not "at the wheels hp." If I order a motor (or motors) rated at 691 horsepower (gas or electric), what that means is that it is the peak horsepower the MOTOR is capable of. If the engine output is limited by other factors, like a low performance fuel pump, transmission, gearing, drag, or a LACK OF ADEQUATE ELECTRICITY, that doesn't mean the motors are not capable of 691 hp. In fact, given adequate electricity, these Tesla motors probably could produce a lot more than that (at a cost of longevity, heat, etc). So, its possible that Tesla is merely limiting its 691 hp motors until adequate test data is available, or to provide another news worthy event by changing a 3.1 sec car to a 2.9 sec car, or some other reason...who knows at this point.

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I agree that if the car is consuming 410 KW that the motor is outputting 550hp at most in situ. Nonetheless, it has nothing to do with the actual hp rating of the motor -- that is completely independant of the amount of power applied to the motor or the amount of energy output in a particular application. Perhaps they will continue to tweak the firmware to apply more power to the engines and change the performance of the car -- but unless they change the hardware, the horsepower rating of the motor will not change.

Thank you LetsGoFast...you are absolutely correct.

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The order page is pretty unambiguous. That rating is the sum of the peak power of the two individual motors: 221 hp front, 470 hp rear. Like all of Tesla's ratings, they are never continuous. While there is no set standard for the exact amount of time for the rating, typically it is on the order of 30 seconds to a 1 minute. The rating will be determined by the nameplate voltage, peak current (for the given time limit mentioned above), and peak rpm (back EMF factored in). Assumption tends to be full load (as that lets you achieve highest number).

It is pretty clear this rating has no regard to the upstream power system (batteries and inverters). The "470hp" motor rating is the same exact motor as the one that was in the P85+ which was rated at 416hp for the car as a whole.

The unique part of the dual motor is that it's entirely possible for the motors to generate 221 hp and 470 hp respectively in the real world (which it might be doing already), but for the car as a *whole* to never make 691 hp because it doesn't do it at the same time for both motors.

Another gold star. Well said.

 

[Andyw2100]

After the hours and hours you've spent on this subject, this never crossed your mind? That perhaps a future update will unleash the car's full potential?

Besides, like the others here, I'm getting nauseated by the endless whining. Every car manufacturer advertises the peak possible engine hp, not "at the wheels hp." If I order a motor (or motors) rated at 691 horsepower (gas or electric), what that means is that it is the peak horsepower the MOTOR is capable of. If the engine output is limited by other factors, like a low performance fuel pump, transmission, gearing, drag, or a LACK OF ADEQUATE ELECTRICITY, that doesn't mean the motors are not capable of 691 hp. In fact, given adequate electricity, these Tesla motors probably could produce a lot more than that (at a cost of longevity, heat, etc). So, its possible that Tesla is merely limiting its 691 hp motors until adequate test data is available, or to provide another news worthy event by changing a 3.1 sec car to a 2.9 sec car, or some other reason. I don't know why this is so hard to understand.

It sounds like you have a lot more expertise and knowledge of the specifics of this than I do. That's fine. I fully acknowledge than I know little about engines, horsepower, etc.

What I do know, though, is that when I was looking at the specs of the car, as Tesla advertised them, and read 691 HP, my expectation was that the car I was purchasing could actually make 691 HP. I think that was a reasonable expectation for an average person like me to hold.

I think the arguments about the car perhaps eventually being able to make 691 HP and the motor theoretically being able to make that much power now, if given enough electricity, are moot points. We weren't buying motors, based on motor specs. We were buying cars.

I maintain that the average person buying a P85D, who read the 691 HP spec expected that the P85D would make 691 HP when they took delivery. It didn't. It doesn't.

For me it's really as simple as that.

 

[WarpedOne]

And you are doing what about that? Posting on a internet forum?

Go demand your money back or a car that you ordered, if you think you did not get what you ordered and payed for.

I maintain that the average person buying a P85D, who read that the 691 HP spec expected that it would make 691 HP when they took delivery. It didn't. It doesn't.

They've said combine motor power. If you misunderstood, it is your problem.
They also say 85kWh. How come you understood what it means?

Horros: as things stand, battery in MS85 is not actully 85kWh but more like 79kWh. Where is the complaining?

 

[Andyw2100]

And you are doing what about that? Posting on a internet forum?

Go demand your money back or a car that you ordered, if you think you did not get what you ordered and payed for.

I was pointing out the flaws in the argument of the poster I responded to. I never said the issue was significant enough for me to want my money back. I do, however, feel somewhat misled.

They've said combine motor power. If you misunderstood, it is your problem.

I'm not sure what your point is, or what part of mine you don't seem to grasp, but based on previous discussions with you, I know you like to stir the pot, so I won't delve too deeply into this.

I'm saying that I am an average person, and that as an average person I had an expectation that 691 HP meant the car was capable of making 691 HP. I think if that is what the average person reading the specs on the Tesla website would expect, then when the car doesn't do that it is not, as you put it "our problem," but rather Tesla's problem. It's possible that people who feel more strongly than I do about this will pursue legal remedy, as you suggest, and then we'll see whether the courts agree with you or with me as to whether Tesla misled people. Until then, we can disagree about whose problem it is.

They also say 85kWh. How come you understood what it means?

Horros: as things stand, battery in MS85 is not actully 85kWh but more like 79kWh. Where is the complaining?

The battery is an 85kWh battery. Some of the capacity is reserved, and is not available for every day driving. That doesn't mean the battery is not an 85kWh battery.

 

[AGT Tactical]

@wk057

As I understand it the original complaint was that Tesla was advertising "691 hp" while they were actually advertising "691 motor hp". Some didn't like this fine distinction. Later Tesla removed the "691 motor hp" description and now the issue seems to be evolving to "yah but at some point they advertised 691 motor hp". Setting that aside for a moment....
Do we know the rear motor (470 hp) is fairly rated/labelled? I believe "yes" from the original P85.
Do we know the front motor (221 hp) is fairly rated/lablled? I get the impression the answer is "yes" from the behavior of recent 85D firmware.
So are we currently at "language is easily interpreted as 'vehicle can apply 691 hp at once in some conditions" '?
I'm going to assume you would say "yes" for the moment.
Thought experiment: If Tesla offers 200 kWh packs in 2020 and one or more individuals manages to get that battery accepted by a 2015 P85D and it's able to deliver "691hp at once" under at least some realistic road conditions, is Tesla's original claim vindicated?

Bravo!

 

[AGT Tactical]

Don't most of the magazines represent "0-60" times with a one foot roll-out, to control for reaction time? I think that is pretty common, where false HP claims aren't. I wish there were an 81 page thread to turn 'TC off'...

Good point. Yes, that is my understanding as well. The one foot roll out is the only practical way to eliminate the often very large difference in people's reaction times.

 

[stopcrazypp]

The battery is an 85kWh battery. Some of the capacity is reserved, and is not available for every day driving. That doesn't mean the battery is not an 85kWh battery.

The "85kWh" rating is the nameplate rating of the battery (similar to how 470hp and 221hp are the nameplate ratings of the motor). The top 5% and bottom 2% are not used. While you can count the bottom 2% as a "reserve" (an unusable one), the top 5% you never see. Thus the "85kWh" battery is functionally no different from a 81kWh battery that is utilizing the top 5% (and 2% in unusable "reserve").

In this same case, the rear motor is a 470hp motor and front motor is a 221hp motor. It is just both are not utilized at peak power at the same time, but that doesn't change the fact they are 470hp and 221 hp motors.

I think the analogy is apt here.

 

[Andyw2100]

I think the analogy is apt here.

If the analogy is apt, that would only make the situation worse for Tesla, not better.

Also, for the lay person, the battery size is somewhat irrelevant. What an average person thinking about buying the car would look at when thinking about battery size isn't how many kWH the battery is, but rather how far can the car go with this particular battery size. That's a discussion for about a hundred other threads, but my point is that the actual size of the battery was probably not a real issue for many average people, but rather what that battery could do.

691 HP, on the other hand, was a number and a description that even to your average consumer held some meaning, at least in rough terms.

I don't think anyone, or at least not nearly as many people would be expressing any concern about this if the 691 HP originally claimed turned out to be 680 HP or 670 HP. But the fact that it isn't even close to that 691 figure is the reason people are writing about it. (I'm not that on top of this, but isn't the general consensus that the max HP is actually well under 600?) The difference is significant.