P85D and P90D horsepower disagreement

[alexrov]

I don't care what the engine power is, when I buy a car I want to know how much power the CAR I have bought has.
To advertise 691hp when the battery/inverter cant deliver it is as stupid as if BMW did advertise the BMW M5 with 700hp but the fuel pump and injectors is only able to deliver enough fuel for 500hp

Funny enough, ICE-vehicle companies like BMW do exactly what you're railing on Tesla against. They advertise the power of the engine, not the amount of power received at the wheels.

 

[MuppetOwl]

Why is the Porsche Panamera Turbo S with only 570hp so similar in performance to the P85D then? The Porsche have about 15-20% drivetrain loss and the engine is ineffective and only produces peak hp on 6000 rpm. Still it is faster than The Tesla in almost everything expect 0-60. Even the rolling start from 5mph where the Tesla should be superior on is almost the same.


Test data from caranddriver

Porsche Left and Tesla right

 

[Sad]

Funny enough, ICE-vehicle companies like BMW do exactly what you're railing on Tesla against. They advertise the power of the engine, not the amount of power received at the wheels.

And this power is actually produced (under some conditions) somewhere inside the car! Not the case for Tesla. The correct BMW analogy would be if BMW advertised the power that an engine *could* produce with a bigger turbocharger. Which they don't. Let's make things simpler: Tesla themselves advertised at the beginning the actual power produced (not sure if it's before or after losses, but at least not a virtual number), and are now doing it again for the 70D and 85D. So they realised that they could not get away with it. For the P85D, they probably don't display it because it would be a huge loss of face, after all the auto reviews fantasized on the ginormous 691 bhp, if they came back to a realistic value (550?). This was so unnecessary, 3.2 secs was super-impressive, 500-550 bhp would not have disappointed, so unnecessary, such a shame. I just hope that this will just be a bad episode, I guess Tesla is lucky that auto-journalists are quite superficial (or that Top Gear is off the air!).

 

[alexrov]

Why is the Porsche Panamera Turbo S with only 570hp so similar in performance to the P85D then? The Porsche have about 15-20% drivetrain loss and the engine is ineffective and only produces peak hp on 6000 rpm. Still it is faster than The Tesla in almost everything expect 0-60. Even the rolling start from 5mph where the Tesla should be superior on is almost the same.


Test data from caranddriver

Porsche Left and Tesla right

View attachment 87844View attachment 87845

There you go; some actual data. You've gone and proven yourself wrong.

First of all, this test was done before the OTA update that increased the P85D performance.

Second, the Porche Panamera Turbo S is a 500lb lighter car than the P85D.

Third, if the P85D really had only 555HP, then why does it perform better than a 500lb lighter car with "15" more horsepower?

 

[dsm363]

Why is the Porsche Panamera Turbo S with only 570hp so similar in performance to the P85D then? The Porsche have about 15-20% drivetrain loss and the engine is ineffective and only produces peak hp on 6000 rpm. Still it is faster than The Tesla in almost everything expect 0-60. Even the rolling start from 5mph where the Tesla should be superior on is almost the same.

Doesn't the Porsche have a 7 speed transmission? That is a big help at higher speeds from what I've read here. Maybe someone who knows a lot more about this can respond.

 

[MuppetOwl]

There you go; some actual data. You've gone and proven yourself wrong.

First of all, this test was done before the OTA update that increased the P85D performance.

Second, the Porche Panamera Turbo S is a 500lb lighter car than the P85D.

Third, if the P85D really had only 555HP, then why does it perform better than a 500lb lighter car with "15" more horsepower?

The difference is 370lb. The Porsche have an much more ineffective engine. Power at the wheels is only about 470-480hp and still it does perform better than the Tesla at higher speeds and almost the same from 0-60. Maybe perform better for you is 0-60 but for me the more important performance is from 50-120 mph and there you need horsepower. Tesla P85D does perform far from a 6-700hp car at that speeds. With the new upgrade pack it is closer to where it should have been from the start.

When I did order the car I was not able to try the car so I had to trust Tesla's 691hp number. P85D has better HP to weight ratio than the Porsche but is still slower.

 

[Sad]

Third, if the P85D really had only 555HP, then why does it perform better than a 500lb lighter car with "15" more horsepower?

Wait, you actually believe that the P85D produces more than that? I thought you were making the argument that it doesn't matter that the P85D did not produce the 691 bhp as this was "motor combined power", as long as it would actually do 0-60 in 3.2 secs which was the important thing. If you actually think that the 691 hp are being produced somewhere in the car, then time to read the numerous posts about the topic.

 

[alexrov]

The difference is 370lb. The Porsche have an much more ineffective engine. Power at the wheels is only about 470hp and still it does perform better than the Tesla at higher speeds. Maybe perform better for you is 0-60 but for me the more important performance is from 50-120 mph and there you need horsepower. Tesla P85D does perform far from a 6-700hp car at that speeds. With the new upgrade pack it is closer to where it should have been from the start.

When I did order the car I was not able to try the car so I had to trust Tesla's 691hp number. P85D has better HP to weight ratio than the Porsche but is still slower.

You're comparing an ICE car's performance with a full-electric, which is apples and oranges. When I buy a car, I expect to be told the peak engine output. If you expect to see that at the wheels 100% of the time for any car you purchase, ICE or Electric, then I don't think there's anything else I can tell you. I think I can just laugh and leave it at that.

Also, for your information:

4,398 lbs
2016 Porsche Panamera Turbo S, Curb weight

4936 pounds
2015 Tesla Model S P85D, Curb weight

That's 538lbs. I was being generous.

(edited for formatting)

 

[MuppetOwl]

Caranddriver list the Porsche Panamera Turbo S to 4638 lb. Maybe you are looking at the model with smaller engine? Or without extras the car caranddriver did test.

 

[sorka]

I hope there is no dispute that they advertised "motor power". You can say it's misleading marketing, but it doesn't change that they advertised it that way.
They advertised as follows (motor hardware didn't change, only advertising):

	2013	2014 "motor power"	2015
S60	302	380	315 (S70)
S85	362	380	362
P85	416	470
S60D		188 F + 188 R = 376	328 (S70D)
S85D		188 F + 188 R = 376	422 (OTA) 261 F + 261R
P85D		221 F + 470 R = 691	221 F + 470 R

This article is a source for the non-D numbers, but there rest you can find references from various announcements and current website.
http://www.greencarreports.com/news/1095000_puzzling-new-power-numbers-for-tesla-model-s-whats-the-deal

There is a lot of telling points in there. Note how S60 went from 302 to 380 "motor power", then back down to 315 for S70. Similar story for S60D 376 "motor power", down to 328 for S70D. S85D is the weirdest. In the European sites it is advertised at 522 "motor power" (261 front + 261 rear) and advertised at 422hp in other sites:
http://www.teslamotorsclub.com/show...aded-85D/page2?p=967457&viewfull=1#post967457

It's pretty clear from the above Tesla never meant that the P85D can output 691 as a whole, and when they say "motor power" they really meant "motor power".


I thought it was established that there is no valid of dyno yet of the P85D on the other thread. Again there are dynos of the P85 making more than 430whp (and critically at the *same* SOCs). Peak REST of that car is ~470hp, peak REST of P85D is ~550hp. If you believe those dyno results, those 80hp just vanished into thin air.

There are few that claimed the few dynos done were invalid. The dyno run where the belt broke was invalid. The dyno run done right after the belt was replaced was completed and didn't suffer slippage. The dyno run where the wheels slipped did so at very low speed long before peak power is produced. The REST highest reading is indeed 550 hp from the battery. That doesn't include dc-dc conversion losses (very minimal), conversion losses of turning electricity into rotation on the motor shaft(also probably minimal), reduction gear losses and finally open differential losses. That said, the entire loss looks like it's a mere 10% which is very very low compared to a traditional ICE going through many more drivetrain components.

Tesla was advertising 691 "motor power" with the numbers combined but they removed it from the website. They were also advertising motor power for the P85 yet the dynos done back up Tesla's claim.

- - - Updated - - -

I had fun catching up on this thread. The new guy comes in completely oblivious to the previous 1000+ post discussions in both forums and walks into all the same traps and then continues to spout stuff that is completely wrong both factually and contextually. Priceless.

 

[gordo]

Alexrov, honestly, you're in over your head. I've read the whole thread, and you still seem to be missing the point.

Sorka has shown you evidence that the P85D makes a peak of 414kw @ 90% SOC. That's about 555hp. I've independently corroborated similar kw numbers with my own P85D. This data comes directly from the car's API. This is the amount of power that the battery pack is dumping into the motors, and it's refreshed every 250ms while you do a run to produce the graphs that you've been shown. This is not the amount of power recorded at the wheels. If it were recorded at the wheels, you'd obviously get even less.

Point is, the P85D does *not* make 691hp (515kw) internally at any speed or state of charge. Now, you may be one of those who believes that this is no big deal and we should just shut up, but you also don't own a P85D, and probably didn't closely follow the announcement, marketing events or published information that was available when the car was introduced, so you're really not going to understand the perspectives of those who did.

To my knowledge no one with a P85D ever expected it to produce 691hp at the wheels, nor did we expect it to deliver a full 691hp for a sustained period. But the way the car was marketed, it seemed as though the car *would* make around 691hp, measured before drivetrain losses, at some point in the acceleration curve, and it clearly does not. In retrospect, I suppose Tesla was trying to get that across with the phrase "motor power" in their marketing, but this was lost on a lot of people and the way it played out seems a bit disingenuous to many folks who purchased the car early on.

Reading between the lines of the announcement of a $5k upgrade for P85D owners six months after they started rolling off the line, it would seem that even Tesla themselves were never quite happy with the way the P85D missed expectations they had for it in terms of performance over 60mph. I honestly believe there was a time that they thought they *could* deliver performance in-line with nearly 700hp, but just couldn't do it in a reliable way prior to launch and had to resort to a separate set of hardware upgrades to achieve what they set out to do in the first place. I don't blame them for the Engineering challenges, and I don't blame them for charging money for the new hardware as there was clearly a bunch of additional R&D expense involved and retrofitting it is going to have some labor costs. However, I still don't believe the best response to those early Engineering challenges was to come up with a creative new way to state horsepower in the hopes that people wouldn't be sophisticated enough to notice the difference.

 

[dennis]

The issue is that, even after more than a few minutes doing research on the issue, there was simply very little to no information on the matter in the first few months after the P85D announcement. And even now, the fact that the old-fuse P85D is only fractionally quicker than the P85 at highway speeds is not really obvious for someone who isn't a forum addict.

But there IS information:

0-60: 3.2 sec
Qtr mile: 11.8 sec @ 115 mph

Simple subtraction yields 60-115 in 8.6 seconds

 

[stopcrazypp]

But there IS information:

0-60: 3.2 sec
Qtr mile: 11.8 sec @ 115 mph

Simple subtraction yields 60-115 in 8.6 seconds

On that note, during the release the comparison was 0-60 3.2 vs 4.4 (1.2 second improvement) and 1/4 mile 11.8 vs 12.6 (0.8 second improvement) which makes it pretty obvious the improvement was in the 0-60 and not the top end.

This article came out shortly after and showed that the main improvement in 0-60 was specifically 0-30 (Elon confirmed that in the announcement yesterday).
http://www.motortrend.com/roadtests/alternative/1411_2015_tesla_model_s_p85d_first_test/

 

[dennis]

The difference is 370lb. The Porsche have an much more ineffective engine. Power at the wheels is only about 470-480hp and still it does perform better than the Tesla at higher speeds and almost the same from 0-60. Maybe perform better for you is 0-60 but for me the more important performance is from 50-120 mph and there you need horsepower. Tesla P85D does perform far from a 6-700hp car at that speeds. With the new upgrade pack it is closer to where it should have been from the start.

When I did order the car I was not able to try the car so I had to trust Tesla's 691hp number. P85D has better HP to weight ratio than the Porsche but is still slower.

Do you understand the concept of gearing? ICE cars have a multi-speed transmission to allow the engine to operate within a RPM band that provides optimal torque and HP for acceleration. Currently electric cars employee a single speed (i.e. no) transmission, which delivers superior performance at low speeds where the engine is producing maximum torque but provides less power as the RPM of the electric motor increases. So you can't infer horsepower comparisons between ICE and electric cars simply my comparing acceleration figures.

Tesla tried a two-speed transmission in the Roadster (before release) but had to abandon the design because it could not stand up to the torque produced by the electric motor. Maybe some future designs will allow electric cars to employ multi-speed transmissions without compromising reliability.

 

[Sad]

But there IS information:

0-60: 3.2 sec
Qtr mile: 11.8 sec @ 115 mph

Simple subtraction yields 60-115 in 8.6 seconds

Well, that's exactly what I did at D reveal time and what cemented my fear that the 691 were just BS (and why I didn't order on the spot even though I was excited like a little boy at Xmas). And it's not like Tesla was displaying that quarter-mile time on their website (it was on the press release only I think). Of course, now, they do. But one shouldn't have to do these gymnastics and use an older model metrics to derive that. Speaking just from the point of view of a buyer of fast cars, what I was really looking for (and still am), was the torque and power "curves" that they used to have for the older models(with max power/torque between X and Y rpm), it was just so refreshingly straightforward at the time.

- - - Updated - - -

Do you understand the concept of gearing? ICE cars have a multi-speed transmission to allow the engine to operate within a RPM band that provides optimal torque and HP for acceleration. Currently electric cars employee a single speed (i.e. no) transmission, which delivers superior performance at low speeds where the engine is producing maximum torque but provides less power as the RPM of the electric motor increases. So you can't infer horsepower comparisons between ICE and electric cars simply my comparing acceleration figures.

Tesla tried a two-speed transmission in the Roadster (before release) but had to abandon the design because it could not stand up to the torque produced by the electric motor. Maybe some future designs will allow electric cars to employ multi-speed transmissions without compromising reliability.

Lack of gearing certainly is a contributor and would allow to keep the max power beyond ... whatever speed power begins to fall off on the P85D (it was around 60-70 mph on the P85), but the main point is that the pre-ludicrous P85D does not produce anything close to 600 or 700 bhp ... ever. If the crest of the power curve was > 600 bhp, and then falling gradually from there, the P85D would be much more competitive at higher speeds. From what it looks like, the ludicrous-mode P85/90D might achieve just that. Fingers crossed!

 

[Pontus]

Has anyone put a 85D on a dyno?

 

[dsm363]

In other news I just found out my 4TB hard drive doesn't actually have 4TB when formatted.

 

[sorka]

And the 85 kWh battery doesn't really have 85 kWh available for driving

 

[dsm363]

Yep. Tesla should be better than the rest in this department but someone decided to advertise the combined hp of both motors directly at the motors even if combined in the car you don't achieve that. It appears they've changed this but the car still delivers breakneck performance at the low end. People who truly care about the 60+mph performance had to know that a car with only 2 gears would likely not perform at the same level as a car with similar reported HP and 7 gears like a Porsche.

 

[thegruf]

Alexrov, honestly, you're in over your head. I've read the whole thread, and you still seem to be missing the point.

Sorka has shown you evidence that the P85D makes a peak of 414kw @ 90% SOC. That's about 555hp. I've independently corroborated similar kw numbers with my own P85D. This data comes directly from the car's API. This is the amount of power that the battery pack is dumping into the motors, and it's refreshed every 250ms while you do a run to produce the graphs that you've been shown. This is not the amount of power recorded at the wheels. If it were recorded at the wheels, you'd obviously get even less.

Point is, the P85D does *not* make 691hp (515kw) internally at any speed or state of charge. Now, you may be one of those who believes that this is no big deal and we should just shut up, but you also don't own a P85D, and probably didn't closely follow the announcement, marketing events or published information that was available when the car was introduced, so you're really not going to understand the perspectives of those who did.

To my knowledge no one with a P85D ever expected it to produce 691hp at the wheels, nor did we expect it to deliver a full 691hp for a sustained period. But the way the car was marketed, it seemed as though the car *would* make around 691hp, measured before drivetrain losses, at some point in the acceleration curve, and it clearly does not. In retrospect, I suppose Tesla was trying to get that across with the phrase "motor power" in their marketing, but this was lost on a lot of people and the way it played out seems a bit disingenuous to many folks who purchased the car early on.

Reading between the lines of the announcement of a $5k upgrade for P85D owners six months after they started rolling off the line, it would seem that even Tesla themselves were never quite happy with the way the P85D missed expectations they had for it in terms of performance over 60mph. I honestly believe there was a time that they thought they *could* deliver performance in-line with nearly 700hp, but just couldn't do it in a reliable way prior to launch and had to resort to a separate set of hardware upgrades to achieve what they set out to do in the first place. I don't blame them for the Engineering challenges, and I don't blame them for charging money for the new hardware as there was clearly a bunch of additional R&D expense involved and retrofitting it is going to have some labor costs. However, I still don't believe the best response to those early Engineering challenges was to come up with a creative new way to state horsepower in the hopes that people wouldn't be sophisticated enough to notice the difference.

+1 well said.