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What will be the new HP numbers for AWD and P after 12.4?
- Thread starter Swampgator
- Start date
MichaelP90DL
Active Member
OK. A little math, then. Torque on my 2015 P90DL is 713 ft-lbs. Fully wound out, I'm told, the motors are spinning at around 16,000 RPM. 713 x 16,000 = 11,408,000 horsepower. Dayum! The usual HP figure for this car is 762. Of course it's possible my calculator is busted. And math and I never did get along. Can someone double check my numbers?
AlanSubie4Life
Efficiency Obsessed Member
Well, I did not divide by 5252, which is required when torque is specified in lb-ft. But I also did not specify units for the torque so that is cool. For my argument above all that mattered was the proportionality anyway, not the units.
And your motor does not generate that torque at that RPM; that is the peak torque.
MichaelP90DL
Active Member
agnostic of motor type. both go spinny spinny.
torque is a rotational force. but it has to be applied at a certain rate (rpm), to understand how quickly work can be done (hp).
if you need to move a resting object, you need to give it at least a shove (a force).
after 1 minute, how many shoves you give it, determines how far it's moved.
thats why power is the final "word" in any contest of speed, because it takes rate into account.
probably was issued marginal torque improvement at lower revs, that tapers off.
on the same firmware, the torque delta across LR AWD vs P was never constant anyway... it seems the bulk of advantage was conferred mostly at lower end
AlanSubie4Life
Efficiency Obsessed Member
You can see earlier in this thread the instrumented data (accelerometer and VBOX) shows 5% torque increase basically all the way up, eventually tapering off at very high speed.
There is really no other way to drop 0.1 seconds off the 0-60 time, which is pretty huge!
btw, qualitatively, this electric motor with flat/constant torque output is way overblown. atleast compared to what i was conditioned to believe. modern engines have torque curves that are just as flat or even better (over their limited range).
of course, the advantage of these electric motors is how well they maintain it for how long....maintaining decent torque output at those stratigraphic revs is something motorcycle engines can only dream of
of course, the advantage of these electric motors is how well they maintain it for how long....maintaining decent torque output at those stratigraphic revs is something motorcycle engines can only dream of
Actually, if you look at the graphs, the motors in the 3 are anything but 'flat' over the entire rev range. BUT they are very good in the 'normal' driving range of speeds, and exceptional at very low speeds.
The usable rev range of the motor, even though the power/torque drops off, and isn't running in it's ideal range is used such that you can avoid a gearbox.
Knightshade
Well-Known Member
Given it's the same physical powertrain as the P, but just being software limited, that's not really all that amazing
AlanSubie4Life
Efficiency Obsessed Member
wait...what...? The torque is basically completely flat from 4mph all the way up to close to 45mph! Ignore the dyno curves below 3000rpm (that is nonsense data). It is that crazy torque at low RPM that people talk about with electric motors... and for the Model 3 it is crazy after about 2-3mph (a few hundred RPM). Yes, torque starts dropping significantly at higher speeds, due to battery and motor limits.
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Take a look at the provided graphs, and by the way it's flat horsepower curves that are being discussed not flat torque curves. It is hardly hype or overblown misrepresentation to suggest that there's really no comparison between the flat horsepower curve generated by the Tesla especially the all-wheel drive motor which is amazingly flat, compared to any gasoline engine ever made. So the notion that it's overblown seems completely unsubstantiated. If you had an internal combustion engine capable of this flat a horsepower curve, you would have gotten a Nobel.
you could tune a motor to produce a flat hp curve - but why would anyone ever want to?
in any given gear, motor speed is linear to road speed. at any road speed (and thus at any motor rpm), you would want the maximum power available for acceleration. that means maximum torque.
at any motor speed, maximum torque is desirable. a flat hp curve requires a monotonically declining torque curve. nobody wants that.
if the ghost of alfred nobel and michael faraday and nikola tesla and nick otto and bosch and benz and atkinson all collaborated together, their ideal engine would produce equal torque at all speeds. be the engine electric or combustion
good point -- i ignored that the lower speeds is artificially hampered due to traction, and only saw a 1.5k - 2k plateau. though yes, even that narrow band translate into wider road speed than on ICE dyno sheet. still, i assumed electric motors basically go flat-out from 0-15k
AlanSubie4Life
Efficiency Obsessed Member
It’s not due to traction since the broad torque peak shows up just fine in the accelerometer data. It is some sort of artifact of the dyno method which is probably not designed to capture immense torque at low RPM. I don’t really know, I just know it is not real and does not translate to the real world.
All electric motors drop off at higher RPM, due to back EMF, as I understand it. There are probably other non-idealities as well; I don’t know much about them really.
That's an impressive collection of geniuses but not all of them together could likely create a constant torque engine at any speed - might be physically impossible in any case. What you're leaving out of your analysis is the advantage of a flat horsepower curve compared to a flat torque curve and it's a big one - you obviate the need for a transmission. That means reduced parasitic loss, reduced complexity, reduced weight, reduced mtbf and last but not least reduced cost. You can't do that with an internal combustion engine. If you could somebody already would have. I'm curious do you actually own a Tesla? You seem fond of the liabilities of ICE. But all the spinning in the world (pun not intended!) doesn't reduce their liabilities.
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reduced weight is good. reduced complexity is good. simpler transmissions are good - if so enabled by the motor.
and what enables that is torque across broad motor speeds. not horsepower.
you engineer for more torque. you get more horsepower as a consequence.
I've been interested in this as well but haven't had an opportunity to baseline my P3D+ on a dyno yet, or do any data logging.
But watching TeslaBjorn on YouTube play around with the CAN intercepted OBD port and Tesla Stats i noticed that there are some kW readings.
I frame peaked the below picture as the maximum values shown, it would be good to grab a log of a power run as that could give you a nice graph.
I think the F Power & R Power are the electrical kW rates being feed to the motors, so not entirely the same as measure HP/kW at the wheels but still useful.
I did find some quotes on the internet that state the efficiency of the motors, with the Front Induction Motor being 93% and the R Motor being 97%. Using all these values puts a ball park peak "motor" output power figure of the Model 3 Performance at 167kW for the Front Motor and 220kW for the Rear Motor for a combined peak output of 387kW (520hp?)
Of course i have no idea how accurate the readings from the intercepted OBD port are, but my assumption is that the systems within the car would know exactly what is being used by the motors.
The above is for a car that to my knowledge hasnt had the performance increase update received, but it wouldn't be hard to establish what the (numbers) improvement is once it is available using these as baseline.
But watching TeslaBjorn on YouTube play around with the CAN intercepted OBD port and Tesla Stats i noticed that there are some kW readings.
I frame peaked the below picture as the maximum values shown, it would be good to grab a log of a power run as that could give you a nice graph.
I think the F Power & R Power are the electrical kW rates being feed to the motors, so not entirely the same as measure HP/kW at the wheels but still useful.
I did find some quotes on the internet that state the efficiency of the motors, with the Front Induction Motor being 93% and the R Motor being 97%. Using all these values puts a ball park peak "motor" output power figure of the Model 3 Performance at 167kW for the Front Motor and 220kW for the Rear Motor for a combined peak output of 387kW (520hp?)
Of course i have no idea how accurate the readings from the intercepted OBD port are, but my assumption is that the systems within the car would know exactly what is being used by the motors.
The above is for a car that to my knowledge hasnt had the performance increase update received, but it wouldn't be hard to establish what the (numbers) improvement is once it is available using these as baseline.
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