P3D horsepower?

[SleeperService]

So has the original question actually been answered?

Cross posted from 36.1 "Master thread:"

If you convert accelerometer data to implied torque and power data using the mass of the car and driver (~1925 kg), the radius of the wheels (~.33 m), and the final drive ratio (9.04, AFAIK), then it looks like I got a boost of ~3.5% peak power, but the area under the curve for power is quite a bit better, which is reflected in the 0-100 and trap speeds at the 1/8 mile mark:

It's looking like the peak power and torque (at the wheels) for the P3D is now ~447 hp and 465 ft-lb.

 

[adrianp89]

What is the difference between 36.1 and 8.4?

 

[SleeperService]

What is the difference between 36.1 and 8.4?

8.4 was post first power bump. 36.1 is post second power bump.

 

[adrianp89]

8.4 was post first power bump. 36.1 is post second power bump.

So the first power bumper increased power for higher speeds and second at lowed speeds?

 

[SleeperService]

So the first power bumper increased power for higher speeds and second at lowed speeds?

Actually, the first power bump was pretty significant at all speeds, the second is much more modest at low speeds and pretty good at higher speeds. I went ahead and calculated and plotted the pre-first power bump data (2019.5.15) for comparison:

 

[neezer]

Actually, the first power bump was pretty significant at all speeds, the second is much more modest at low speeds and pretty good at higher speeds. I went ahead and calculated and plotted the pre-first power bump data (2019.5.15) for comparison:

View attachment 473753

SleeperService, you da man! Thanks. This is very exciting. We need a M3P with this and 90%+ SOC to run that half-mile race against the C63S Benz to show Top Gear how it's done ...

 

[AlanSubie4Life]

Actually, the first power bump was pretty significant at all speeds, the second is much more modest at low speeds and pretty good at higher speeds. I went ahead and calculated and plotted the pre-first power bump data (2019.5.15) for comparison:

View attachment 473753

This plot is wonderful. So much information, answers so many questions which are asked over and over again. Thank you.

 

[frankusb]

Actually, the first power bump was pretty significant at all speeds, the second is much more modest at low speeds and pretty good at higher speeds. I went ahead and calculated and plotted the pre-first power bump data (2019.5.15) for comparison:

View attachment 473753

Should one of the 2019.8.4 data sets show HP? The blue? And one of the 2019.5.15 data sets is missing a label completely.

 

[AlanSubie4Life]

It's hard to notice when it's happening. I only noticed the power reduction dots watching a video from some half mile runs I did. Here are a few screen shots from the video. Interestingly even though the pedal is floored the "power bar" doesn't go to 100% until about 35mph but doesn't show any power reduced dots. After about 49mph you can see the bar starts to drop but the car is still floored and no dots are visible. After that it continues to drop and reduced power dots show up but go away as soon as the pedal is lifted and the bar starts back towards the regen side. So it seems the reduced power dots only show as the car is limiting power. Unlike the reduced regen dots that basically warn you that or won't be at full regen. It'd be nice to know that your car is going to reduce power before it actually reduces power.

That is interesting behavior, though it seems to show power reduction after sustained maximum discharge, which is not as lengthy for a 0-60 sprint.

As far as your power bar not reaching max until 35-40mph, that is no surprise, and unrelated. Remember nearly zero power is required to accelerate at maximum g’s at low speed. And only half of maximum power is required for maximum acceleration at say ~20mph. Since HP is proportional to Torque*Speed. (As can clearly be seen in the awesome plots.)

Note also the power bar does not use a linear scale.

 

[SleeperService]

Should one of the 2019.8.4 data sets show HP? The blue? And one of the 2019.5.15 data sets is missing a label completely.

Yep, I see that. Missed it, and missed the edit window to change it. I think the plots should be pretty obvious from context though? My bad...was in a hurry! haha

 

[frankusb]

Yep, I see that. Missed it, and missed the edit window to change it. I think the plots should be pretty obvious from context though? My bad...was in a hurry! haha

I think they are obvious, your data is much appreciated. I forgot about the edit window.

 

[neezer]

@SleeperService (and anyone else really), care to share with us the reason(s) why battery-powered vehicles, or Teslas in general, seem to need to be hugely limiting their torque output at higher speeds? Looks like ~150hp @ 100mph for the latest update. Why so little relatively speaking? Thx

 

[Paddy3101]

Actually, the first power bump was pretty significant at all speeds, the second is much more modest at low speeds and pretty good at higher speeds. I went ahead and calculated and plotted the pre-first power bump data (2019.5.15) for comparison:

View attachment 473753

Great data. Shows the relative increase.

Does your calculation take into account drag? If not, would mean the absolute/headline number would be slightly higher. Not that it matters really, it's the comparison which is important.

 

[SleeperService]

@SleeperService (and anyone else really), care to share with us the reason(s) why battery-powered vehicles, or Teslas in general, seem to need to be hugely limiting their torque output at higher speeds? Looks like ~150hp @ 100mph for the latest update. Why so little relatively speaking? Thx

I'm not an electric motor engineer (although I am an engineer, in case it wasn't obvious...), so someone that is more expert than me may chime in to correct me, but much of the power drop off at higher motor speeds is due to back EMF (voltage induced in the motor by it spinning in an electromagnetic field...basically it becomes a generator even though you don't want it to) reduces the effective voltage delivered to the motor, and that causes a commensurate drop in available torque. And because power is proportional to torque * motor speed, power drops off too. It's more complicated than that, since these are pretty advanced motors, and the rear motor and the front motor on the dual motor Model 3s are different types, but I think that covers the gist of it.

 

[SleeperService]

Great data. Shows the relative increase.

Does your calculation take into account drag? If not, would mean the absolute/headline number would be slightly higher. Not that it matters really, it's the comparison which is important.

It does not include drag, no. I think someone posted drag force vs. speed curves at some point, so it wouldn't really be that hard to add...but as you say, it shows the relative difference which is more relevant anyway. It also doesn't take into account the rotational inertia of the wheels, tires, brake rotors, drive shafts, gears, or motors...so it is definitely underestimating the power to a certain extent.

 

[AlanSubie4Life]

Looks like ~150hp @ 100mph

*325HP at 100mph. Weak, but may be sufficient. Acceleration will be a pathetic 0.3g or so though at that speed. How are we supposed to merge with traffic?

 

[Paddy3101]

So, looking at the graphs, it's now producing more power, all the way from 40mph up to 75mpg than the original did at peak....
And the power it was producing at 70mph, it's now producing at 90mph.

That's why it feels (to me) that the power is much 'fatter', and extended, and the throttle response is different.
Even compared to 8.4 there is a 10-15mph difference in the spread of the power.

 

[Paddy3101]

*325HP at 100mph. Weak, but may be sufficient. Acceleration will be a pathetic 0.3g or so though at that speed. How are we supposed to merge with traffic?

You've got about 50hp of drag at 100mph, so really, its about 375HP.

Or another way to look at it, you have 325HP to play with AFTER you have accounted for drag...

 

[neezer]

My bad, yes. The torque figure in lb-ft is what's at 150 ;-)

 

[yerEVan]

Actually, the first power bump was pretty significant at all speeds, the second is much more modest at low speeds and pretty good at higher speeds. I went ahead and calculated and plotted the pre-first power bump data (2019.5.15) for comparison:

View attachment 473753

it's amazing how you were able to stop the car, instantly, at 100Mph on all 3 runs. awesome brakes.

{dry humor}