P85D Power draw numbers do not add up...

[Sad]

Fun to play around with numbers :smile:. If I assume flat higher torque, i.e. linear power progression, until 40 km/h (instead of the current 65 km/h), then flat 300 kW power between 40 and 100, I arrive to a 0-100 km/h time of 3.4 seconds... which is exactly what Tesla is quoting. Replacing 40 by 65 yields 4.2, which is not too far from what the P85 can do...
The assumption behind the 40 km/h peak torque is that the higher torque produced by the two engines allow peak power to be reached much quicker.

My simplistic math:
Kinetic energy at 100 km/h: 0.24 kWh
I assume an average of half the power between 0 and 40, i.e. 150kW, which requires 0.93 seconds to make it to 40
I then assume a constant power of 300 kW to move from 40 to 100, i.e. provide 0.20 kWh of kinetic energy, that will require 2.45 seconds.

So maybe the car can make it by having peak 350 kWh (what my current MS is rated at in Switzerland), after accounting for losses.

 

[kennybobby]

Hey WK i've been struggling with what you've brought up also. The datasheet for the fuse is cryptic and not clear at all, but on further investigation i found the following curve data. Bussmann claims the fuse is good to operate below the A-A line, which indicates it can withstand about 1900 Amps for 30 seconds! Seems unbelievable. It can run at the 630 rated amps continuously although it is drawing 80 watts--hence the sort of FLIR temperature data you measured.

 

[Cottonwood]

Hey WK i've been struggling with what you've brought up also. The datasheet for the fuse is cryptic and not clear at all, but on further investigation i found the following curve data. Bussmann claims the fuse is good to operate below the A-A line, which indicates it can withstand about 1900 Amps for 30 seconds! Seems unbelievable. It can run at the 630 rated amps continuously although it is drawing 80 watts--hence the sort of FLIR temperature data you measured.

Well, that seems to be good for 690 hp for a couple of 0-60 runs...

 

[dan-l]

Kennybobby is right, and hats off to you sir on reading that curve. Personally I find the data sheet much less cryptic this lists the I2t as 52k which means the fuse will begin to arc when current x time go above the number 52,000. So 1900a x 30s =57,000=fuse blown. But 1900a for 10-20s and you're OK.. You've just got a really hot fuse.

 

[Perfect_Flaw]

The D likely uses a slightly different pack.

As for the numbers being a marketing ploy: Guys, we're talking about accelerating a nearly 5,000 lb sedan to 60 mph in 3.2 seconds, faster than a 700+ hp Hellcat. Do you really think that 691 hp number is far from reality?

The Charger Hellcat is certified to run a 0-60 time in 2.9 seconds. Not sure where Tesla came up with the "fastest sedan in the world" thing, but maybe they have yet to hear about the Hellcat. Not to mention, a Hellcat from a 60 roll will absolutely destroy a P85D and trap at over 126-128MPH in the 1/4 mile, where the P85D will be lucky to hit 112-113MPH as the power curve falls off a cliff after 60mph. P85's are quick out of the hole, but after that, they really lose power quickly.

Also, the Hellcat will run a 10.8 second 1/4 mile with drag radials and 11.2 on street tires. The P85D claims a 11.8 1/4 mile time. How can Tesla claim "fastest production sedan in the world" when clearly the Hellcat beat them to the punch? Sounds like Tesla's marketing team needs to be sat down and talked to.

 

[wk057]

Hey WK i've been struggling with what you've brought up also. The datasheet for the fuse is cryptic and not clear at all, but on further investigation i found the following curve data. Bussmann claims the fuse is good to operate below the A-A line, which indicates it can withstand about 1900 Amps for 30 seconds! Seems unbelievable. It can run at the 630 rated amps continuously although it is drawing 80 watts--hence the sort of FLIR temperature data you measured.

Ah very nice, I wasn't able to find this. That makes a lot of sense then. As long as the software is able to appropriately limit the power draw then this would work.

 

[EarlyAdopter]

Could this be the root of power limiting after a few spirited laps on the track? Is the car going into limp mode to keep this fuse from overheating and blowing?

 

[Todd Burch]

The Charger Hellcat is certified to run a 0-60 time in 2.9 seconds. Not sure where Tesla came up with the "fastest sedan in the world" thing, but maybe they have yet to hear about the Hellcat. Not to mention, a Hellcat from a 60 roll will absolutely destroy a P85D and trap at over 126-128MPH in the 1/4 mile, where the P85D will be lucky to hit 112-113MPH as the power curve falls off a cliff after 60mph. P85's are quick out of the hole, but after that, they really lose power quickly.

Also, the Hellcat will run a 10.8 second 1/4 mile with drag radials and 11.2 on street tires. The P85D claims a 11.8 1/4 mile time. How can Tesla claim "fastest production sedan in the world" when clearly the Hellcat beat them to the punch? Sounds like Tesla's marketing team needs to be sat down and talked to.

Nobody claims the P85D is faster than the Hellcat in the quarter mile. We're talking 0-60 here.

The Hellcat's own website claims Quickest Sedan Ever, but they explicitly are referring to quarter mile time. Yes, the Hellcat has a faster quarter mile time. Tesla claims quickest 0-60, and it likely is.

As for 0-60, the Hellcat website itself claims "low 3-second range" for 0-60. Road & Track measured 3.7 sec for the Hellcat 0-60 (source), and Motor Trend measured 3.7 sec (source). And here, Motor Trend said Dodge claims 3.7 sec. Recall that Tesla's performance specs tend to be a little on the conservative side (for example, in 2013 the P85 clocked in at 0-60 in 3.9 sec). No matter how you look at 0-60, they are both extremely close. On street tires, the P85D's numbers are slightly faster. Of course we'll have to wait for Youtube Hellcat vs. P85D videos, but the key difference is that Tesla is claiming quickest 0-60 (which is likely is) and Dodge based on quarter mile (which it surely is).

 

[Perfect_Flaw]

Could this be the root of power limiting after a few spirited laps on the track? Is the car going into limp mode to keep this fuse from overheating and blowing?

I would assume it is the battery pack getting hot. Full EV's have a LONG time to go before they can hit the track for a few laps, or even complete a single lap around the Nurburgring before going into limp mode. Even a Ford Focus could run much better times on the Nurburgring than a Model S P85. The Model S is a great street car made for some 0-60 bursts and occasional 1/4 mile sprints, thats it fellas.

 

[Todd Burch]

Even a Ford Focus could run much better times on the Nurburgring than a Model S P85.

Source? There are two videos/articles about a Model S on the Nurburgring that I know of. One, part of a "journalist" review, was actually using a 60 kWh model. In other words, a useless piece of journalism. The other was of Bjorn Nyland, who a) was not racing or driving aggressively and b) is not a professional driver.

Don't get me wrong...I agree that the Model S really isn't a track car...but it sure as hell will beat a Ford Focus.

 

[Perfect_Flaw]

Nobody claims the P85D is faster than the Hellcat in the quarter mile. We're talking 0-60 here.

The Hellcat's own website claims Quickest Sedan Ever, but they explicitly are referring to quarter mile time. Yes, the Hellcat has a faster quarter mile time. Tesla claims quickest 0-60, and it likely is.

As for 0-60, the Hellcat website itself claims "low 3-second range" for 0-60. Road & Track measured 3.7 sec for the Hellcat 0-60 (source), and Motor Trend measured 3.7 sec (source). And here, Motor Trend said Dodge claims 3.7 sec. Recall that Tesla's performance specs tend to be a little on the conservative side (for example, in 2013 the P85 clocked in at 0-60 in 3.9 sec). No matter how you look at 0-60, they are both extremely close. On street tires, the P85D's numbers are slightly faster. Of course we'll have to wait for Youtube Hellcat vs. P85D videos, but the key difference is that Tesla is claiming quickest 0-60 (which is likely is) and Dodge based on quarter mile (which it surely is).

Most car enthusiasts agree, 0-60 times are a worthless indicator of a cars performance because of so many variables. Its a marketing gimmick that caters to non-enthusiasts as a standard benchmark number.

How anyone can call a car the 'fastest-anything-in-the-world' based off of 0-60 times is just plain stupid, sorry. Sure, its quick out of the hole- but thats it- it is not fast over 100MPH, it tops out at 155MPH (the Hellcat can reach 200MPH+), its 1/4 mile time is equal to most 500-550HP ICE sports sedans, and it most certainly cannot run a quick lap time around a track comparable to most any sports sedan out there from BMW M, AMG, Porsche, etc. Remind me again how the P85D is "the fastest production sedan in the world" when the only metric being used is 0-60 times??? Sorry, if it can't beat another production sedan around a track in a single lap, or hit as high of a top speed as another sedan, than it is NOT the fastest anything in the world.

When you see something claiming "Fastest PLANE in the world" or "Fastest car in the world" what metric do they use? TOP SPEED people.

Be happy with your P85's and if buying a new Tesla, buy a used P85 because the premium for a P85D is simply not worth it for a quicker 0-60 time. Better yet, you want fast? Buy a used P85 (since many will be flooding the used market soon) as a daily driver and an SRT Hellcat for $60K as a fun track car with your 2.9 second 0-60 times, 10 second quarter miles, and 200MPH top speed.

- - - Updated - - -

Source? There are two videos/articles about a Model S on the Nurburgring that I know of. One, part of a "journalist" review, was actually using a 60 kWh model. In other words, a useless piece of journalism. The other was of Bjorn Nyland, who a) was not racing or driving aggressively and b) is not a professional driver.

Don't get me wrong...I agree that the Model S really isn't a track car...but it sure as hell will beat a Ford Focus.

Wheres your source for a Ford Focus getting beat by a Model S?

Fact of the matter is, the Model S gets too hot to run a quick 14 mile lap around the Nurburgring.

Heres the video showing you how the Model S overheated and went into limp mode, and they did use a P85.

Nürburgring Proves Too Much For Tesla Model S: Video

- - - Updated - - -

Source? There are two videos/articles about a Model S on the Nurburgring that I know of. One, part of a "journalist" review, was actually using a 60 kWh model. In other words, a useless piece of journalism. The other was of Bjorn Nyland, who a) was not racing or driving aggressively and b) is not a professional driver.

Don't get me wrong...I agree that the Model S really isn't a track car...but it sure as hell will beat a Ford Focus.

Oh, by the way, heres a video of a Ford Focus RS running a 7:58 lap in the Nurburgring- the P85 ran an almost 11 minute lap, and if it didn't overheat they THINK it MIGHT run a 9 minute laptop time. Ouch.

https://www.youtube.com/watch?v=GFHm3qga9bA&safe=active

 

[Todd Burch]

Heres the video showing you how the Model S overheated and went into limp mode, and they did use a P85.

Nürburgring Proves Too Much For Tesla Model S: Video

Nope. That's the very video I was referring to. Look in the comments, and the driver (Robb Holland) mentions that he was driving the 60 kWh base model:

 

[EarlyAdopter]

I would assume it is the battery pack getting hot.

We still don't know. This is a new piece of information. Would be nice if someone could run the numbers and see if this could be the weak link for track limiting.

The battery is liquid cooled with radiators up front. I've got to believe that battery heat isn't the issue here. Or, if it is, that would be readily addressable aftermarket.

Full EV's have a LONG time to go before they can hit the track for a few laps, or even complete a single lap around the Nurburgring before going into limp mode.

If by "a LONG time to go" you mean a year and a half ago, then ok. Otherwise, I think you missed this:
Electric SLS sets new Nurburgring record - BBC Top Gear

Even a Ford Focus could run much better times on the Nurburgring than a Model S P85. The Model S is a great street car made for some 0-60 bursts and occasional 1/4 mile sprints, thats it fellas.

Last time I checked, the Model S was a great street car made for a whole lot of other reasons, like filling up at home, hauling my wife, 2 kids, and parents at the same time, the environment, etc.

 

[stopcrazypp]

Most car enthusiasts agree, 0-60 times are a worthless indicator of a cars performance because of so many variables. Its a marketing gimmick that caters to non-enthusiasts as a standard benchmark number.

Maybe it's a marketing gimmick, but it's a benchmark number that everyone looks at (even more so than 1/4 mile times) and practically every manufacturer provides.

When you see something claiming "Fastest PLANE in the world" or "Fastest car in the world" what metric do they use? TOP SPEED people.

Perhaps "fastest" is not the best term, but "quickest" would describe 0-60 perfectly. However, a lot of times these terms are used interchangeably.

Wheres your source for a Ford Focus getting beat by a Model S?

Fact of the matter is, the Model S gets too hot to run a quick 14 mile lap around the Nurburgring.

Heres the video showing you how the Model S overheated and went into limp mode, and they did use a P85.

Driver said car showed 190 miles of range when fully charged, so a 60kWh for sure, not 85kWh.
http://jalopnik.com/too-smart-for-me-the-car-originally-showed-around-190-1601938374

 

[J1mbo]

Pretty sure they call it the quickest four-door sedan. Hellcat is a two door car, right?

So how long and how far do we think the D cars can run at 155mph from full to flat?

 

[JST]

Pretty sure they call it the quickest four-door sedan. Hellcat is a two door car, right?

So how long and how far do we think the D cars can run at 155mph from full to flat?

You can get the Hellcat engine in either the Challenger (2 door) or Charger (4 door).

 

[arg]

the P85D will be lucky to hit 112-113MPH as the power curve falls off a cliff after 60mph. P85's are quick out of the hole, but after that, they really lose power quickly.

This is supposed to be one of the respects in which P85D will be superior to P85, due to the different gearing on the front motor and (assumed) higher maximum total power.

We don't yet have any figures to say exactly how much so.

 

[JRP3]

I would assume it is the battery pack getting hot. Full EV's have a LONG time to go before they can hit the track for a few laps, or even complete a single lap around the Nurburgring before going into limp mode.

Not true, as the already posted Merc example shows. Plus there are higher C rate battery chemistries available that would allow a full speed Ring run, if that were an important goal, which it is not. 0-60 times are the most often compared performance times between vehicles, so your claim otherwise does not meet with reality. 0-60 times can actually be used in the real world, where top speed and 1/4 mile speeds are much less useful.

 

[mknox]

Well, that seems to be good for 690 hp for a couple of 0-60 runs...

Yeah, but it's a fuse. What happens if you do more than a couple of runs? Battery pack replacement?

 

[Cottonwood]

Yeah, but it's a fuse. What happens if you do more than a couple of runs? Battery pack replacement?

The car could easily log current vs time and model the cooling of the fuse. Maybe protecting the fuse is one of the things that causes a Tesla MS to go into "wimp" mode on the track...