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ArtInCT
Always Learning
Cloxxki, this is a great idea. One that I think Tesla Motors should hear, understand and explore. Do you think that with the lower revs, the power consumption would decrease in the form of lower Wh/mile?
Back in my day, on American Muscle cars of the 60's and 70's you could order various rear end gear ratios or later on, have the dealer install them for you as a "speed" part/service. So with tall 4.xx rear end gears we could go very fast off the line and if you wanted top end speed the 3.3x was the way to go.
Yes. I wasn't going to post just to correct it, but he does have viscosity backwards.
There are also oil options that have pretty low viscosity - though I'm not sure how well they handle the heat or what sort of heat transfer characteristics they have.
Cheers.
I honestly wouldn't know, I'm not exactly well informed on electric motor properties.
People write all the time that the low top-end torque (acceleration) in Tesla S/X comes from the high revs. These motors have each their own torque curves, and (I suppose) conditions (load and rpm) where they perform optimally. If 100mph cruising is already pushing it (not stating, proposing), why not lower that figure through a longer ratio?
Obviously, a win in the top end should bring forth a loss at the low end. City performance (nippiness, consumption) will suffer. But, by how much? And, to a German sales person also on the Autobahn, why would he care?
I am a mountainbiker, and my speciality (3 national ungoverned titles) is singlespeeding. One chainring on the crank, one cog on the rear wheel. I pick my gearing for the ride at hand. Commuting > 42x15. Flat singletrack 34x17. Road crit 52x16. Seriously hilly trails 34x20. Etc, etc. Tesla is the monster that can do it all in one gear. But it could be better at the top end, while it's absolute world leader in 0-60, which is just not necessary to anyone in a clean and silent family car. Until Tesla started doing it.
If I bought a P100DL, I'd like to choose between drag&city gearing, and Autobahn gearing. And foremost, I'd like to have insight into the economy figures to be attained. To be clean as can be, and get most range for my buck. The range may not vary too much, but throttle response in an Autobahn overtake, could be quite different, especially if heat could be reduced every so slightly.
Well, the drivetrain is already tire traction limited, so it seem to make sense that they can put in taller gearing or adjust the torque curve optimization to enhance higher speed operation. Further, I'm interested to know if Tesla is working on switching from ceramic bearings to magnetic bearings for zero friction rotation and therefore the possibility of spinning much faster. I am curious how magnetic bearing motors actually handle spin up from dead stop.
Yup, I setup this thread for poll on who won.
[Poll] Drag race of the century - Rimac EV hypercar vs Porsche 918 Hypercar
I'm not sure how much difference the fancy bearings will make if the rotor is still liquid cooled - presumably the viscous losses in the coolant far exceed the bearing losses, but without the liquid coolant the motor loses the ability to sustain higher power levels for any period of time. Unless Tesla can set up some sort of fancy evaporative cooling system/heat pipe...
lolachampcar
Well-Known Member
Back EMF limits motor RPM way more than friction. RPM per Volt is a common specification for brushless DC motors (thus likely similar for induction AC) where, for a given voltage, the motor will only spin to a certain rpm without too much regard for bearing losses (within reason of course - running on sandpaper bearings would slow things down a bit).
The model a is not a performance sedan nor does it appear that tesla means for it to be given on the complete lack of attention given to the handling, braking, post launch/rolling start acceleration, range at full tilt, and cooling and it shows as the model s sucks at all of the above. It's more of a luxury sedan that happens to be able to launch good. I don't think the model a needs a second gear because it is a luxury sedan, not a performance one. Now if tesla was going to build an actual performance sedan or a 2 seat sports car, they would address all of the issues I listed and add a second gear and cut a LOT of weight.
lolachampcar
Well-Known Member
Uncle Paul
Well-Known Member
Option that Tesla will first employ (if not already being done) is to have different gear ratios in the front and rear drives.
This would give you excellent torque at lower speeds, and enhance high speed performance.
Not sure a large percentage of owners would really care. They currently have great performance, and perhaps little is really to be gained.
This would give you excellent torque at lower speeds, and enhance high speed performance.
Not sure a large percentage of owners would really care. They currently have great performance, and perhaps little is really to be gained.
lolachampcar
Well-Known Member
Adrian
Title(D)
The car will correct and adjust for different tire sizes front/rear - in theory you should be able to trick the preprogrammed power curves this way before the car has time to correct...
I think it uses wheel rotation sensors and compares to GPS to automatically calibrate the speedometer.
Who knows how it would handle different sized tires in an AWD setup. (In theory it could.)
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