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[updated with *] P85D 691HP should have an asterisk * next to it.. "Up to 691HP"
- Thread starter krisg81
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- Driving Dynamics Model S
jerjozwik
Active Member
happen to be friends with someone at CR. i asked about SOC and how many runs were done prior to the final number, "3.5 Sec number is average of number of runs from fully charge (based on tesla's standard setting). More details will be up on our website in next few weeks."
I think we're way beyond whether or not the P85D produces the power it advertises. That question had been settled and further tests does nothing but confirmed what has been suspected all along. The discussion should really focus on how Telsa plans to solve this issue. Their current plan of "let's ignore it, it'll go away" will probably not work in the long term.
That is a very interesting response, because the thrust of that article is that an electric car doesn't need as many horsepower. I'd certainly agree with him that an electric car with 500hp is a much faster and more capable car than an ICE with 500hp, but it doesn't really help when you claim 691hp and don't seem to deliver it.
That's right, and it's especially true that a 500 hp EV is going kill a 500 hp ICE because the power band is so wide that the EV makes much more power at very few RPMs compared to the ICE resulting in killer off the line performance(which is why the P85D is faster to 60 than ANY ICE that has the same power to weight ratio). That advantage drops to almost nothing when you you're already at speed where the ICE's multi speed transmission can keep it near it's peak power almost all the time.
Andyw2100
Well-Known Member
I had the exact same thought when I read it yesterday, and almost posted. If I had, I also would have asked if anyone here might have any idea why Tesla's head of communication would post something like that. It certainly does not strengthen their position on the horsepower issue in any way.
stopcrazypp
Well-Known Member
It should be clarified that he linked the article in his tweet. The article was not written by him.
Andyw2100
Well-Known Member
Yes, I know. I read the article. And I realize you may just be clarifying for others. It's true it would make even less sense if he had written the article himself, but it still makes little sense.
Actually, I completely forgot about this post where I compared my performance box data to data posted about the McLaren F1:
Johan
Ex got M3 in the divorce, waiting for EU Model Y!
This tactic is known as obfuscation and works poorly on an educated and intelligent crowd, actually it causes even more irritation.
Q: "Why are you lying about the number of horsepowers?"
A: "But the car is so fast and shiny. And did I mention it's electric? And fast?"
Andyw2100
Well-Known Member
The letter is ready. I have started two new threads: one to discuss the letter, if that is necessary, and one to collect support and signatures. Both threads include the letter in the first post.
Here are the links to the two threads:
http://www.teslamotorsclub.com/show...Regarding-P85D-Horsepower--Discussion-Thread
http://www.teslamotorsclub.com/showthread.php/51923-Letter-To-Elon-Musk-Regarding-P85D-Horsepower-%C2%96-Signature-Thread-Only-Please
If you have any questions, please post them in the discussion thread.
Thanks!
When you are talking about measuring acceleration such as 70-90mph between cars you would of course make sure the turbo is spooled up and you are in the right gear, hence the RS7 would be fast.
In between the engine and the tires you have gearing. What you feel when you accelerate is the torque applied to the tarmac, not a horsepower figure of the engine.
Saying the Tesla wouldn't make use of gearing because of the flat power curve is just not understanding the fundamentals. As Saleen experimented with your Tesla would accelerate much faster with a new final drive ratio of for example 12 instead of 9,73 - still using the same engine and horsepower figure. Your top speed would of course be hurting. And by the way, the RS7 also has a very flat a power curve.
Because of this you can't directly compare hp vs weight between cars with different gearing, neither by feel nor by acceleration.
In between the engine and the tires you have gearing. What you feel when you accelerate is the torque applied to the tarmac, not a horsepower figure of the engine.
Saying the Tesla wouldn't make use of gearing because of the flat power curve is just not understanding the fundamentals. As Saleen experimented with your Tesla would accelerate much faster with a new final drive ratio of for example 12 instead of 9,73 - still using the same engine and horsepower figure. Your top speed would of course be hurting. And by the way, the RS7 also has a very flat a power curve.
Because of this you can't directly compare hp vs weight between cars with different gearing, neither by feel nor by acceleration.
No, you can't feel it. It's not the same thing. Try telling someone to tighten a screw using horsepower instead of torque as a measurement. Torque is a measurment of force, horsepower is a measurment of power.
Edit: These kind of uneducated responses pops up on almost every single page. If all you want to do is respond to the thread and don't care about the topic then I'm out of here. This is exhausting.
I personally have never used a comparison to ICE vehicles.
I think you have the misunderstanding here. Horsepower is simply a measure of power. It is directly interchangeable with watts in that it is ~746W per HP. In the case of the P85D the power going out is in the best test we've seen about 415kW, which is ~555HP.
No one ever said the car didn't produce as much torque as advertised (since it wasn't even advertised when I bought mine anyway).
Sorry, you're right, I should have taken more time to elaborate on my answer. I agree that wheel torque is what you're going to feel. However, do you agree that power at the wheel will be the product of torque and RPM of the wheels? So at the same given speed, producing 500hp or 20% more will directly influence the wheel torque with the same ratio. Now, the question is what is the hp available at such a given speed? Gearing will indeed determine that as it is the ratio between wheel RPM and engine RPM. However, if we assume that the power curve is flat, i.e the same for the engine RPM of a 1st gearing ratio and for the engine RPM of a 2nd gearing ratio, gearing will have zero effect, at that given speed at least. A different gearing, for an electric car, is going to influence the dynamics of the car where the curve is not flat, basically scaling the power/speed curve to the left or the right, but the flat part of the curve will still be at the same level, but applicable for a different speed interval. If the flat part is wide enough, gearing is unlikely to influence the behaviour of the car for a significant speed interval. And for acceleration, power/weight ratio will be the main direct contributor, until air resistance starts playing a significant role.
jerjozwik
Active Member
just a thought, pretty much every car out there with 500+ hp has an internal combustion engine, which makes its power at the highest RPM. high rpm usually translates to high rate of speed, so.. since the p85d makes the most power at 0 RPM, and the least amount at high speed doesn't that invalidate and argument that the car does not pull like a 1hp for 7lb car at speed?
take for instance my day to day drive with a fiat 500e, tiny hp figure but is plenty quick at 0 mph. but... at 70mph acceleration is dramatically cut short because the motor is spinning at around 11,000 rpm at that point and does not create enough HP.
so what do we know about the p85d power curves in relation to RPM and MPH?
take for instance my day to day drive with a fiat 500e, tiny hp figure but is plenty quick at 0 mph. but... at 70mph acceleration is dramatically cut short because the motor is spinning at around 11,000 rpm at that point and does not create enough HP.
so what do we know about the p85d power curves in relation to RPM and MPH?
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No, max torque is produced at 0 RPM, max power comes later, around 30 mph probably. We don't know what the P85D curve looks like for sure, for the P85, Tesla communicated specifically the RPM interval at which max power occurs (which translated to speeds between 40 and 70 mph), they unfortunately stopped doing that... for now obvious reasons. In any case, dyno runs and REST API logging have shown the flat-ish power band of the P85D to be quite wide, but way below 691hp, so a multi-ratio gearbox would not help at all, expect maybe at the top end when power starts to decrease again.
Max power comes at 36 MPH at 100% SOC when the battery is putting out 414 to 415KW.
It would be the case that max torque occurs at 0 RPMs but that's also not true for the P85D only because the power is tapered up rather than starting at 414KW otherwise all 4 wheels would just spin. The P85D hits peak torque around 19 MPH:
First image with torque at motor shafts splitting the difference between the 9.73 and 9.35 final drive ratios. Second image is torque at the wheels.
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This is not start the whole ydeevne vs performance vs motor power - but this is just to show you how Tesla uses the word ydeevne on the Danish site. Along the use next to the HP it is also used describing the model X. Here they use the word Ydeevne as Performance, which is the meaning of the word.
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