6 ms·
10,000 NM of torque. That's INSANE. I drive a car with 400NM torque and that thing scares the sh*t out of me when I accelerate. 10,000 NM? Isn't that something
by neya 9y ago
10,000 NM of torque. That's INSANE. I drive a car with 400NM torque and that thing scares the sh*t out of me when I accelerate. 10,000 NM? Isn't that something along the lines of a tram or a train (I'm not sure, I'm asking you guys). This is CRAZY. I'm getting one for sure.
- aerovistae 9y agomay i ask what you do for a living
- mmjaa 9y agoIf you can afford one of these cars, you probably don't do anything for a living.
- grkvlt 9y agoI'd suggest the exact opposite - if you can afford one of these cars, you must be working very hard at be very good at whatever you do for a living.
- Sohcahtoa82 9y agoI work in cybersecurity. I'll have to set money aside for a couple years to make a considerable down payment, but I might be able to afford one of these.
- danappelxx 9y agoI had the same thought [0]! They cite their wheel torque, not their engine torque, which is what we're all used to seeing. [0]: https://news.ycombinator.com/item?id=15719411 https://news.ycombinator.com/item?id=15719411
- JulianMorrison 9y agoIn electric cars, isn't it basically the same?
- amdavidson 9y agoEven if there is not a traditional transmission, there is still a gearbox behind the electric motor. Tires only rotate at ~1000 RPM on the freeway where the electric motor in a Tesla might be at 10k rpm. That 10x reduction still needs to be factored in.
- InternetOfStuff 9y agoHonest question: did you just make up these numbers, or are they based in fact? I was expecting the motor to turn slower.
- balfirevic 9y agoNot OP, but Tesla Model S has approximately 1:10 fixed gear reduction. Motor RPM will go higher than 10000 RPM at really high speeds.
- Robotbeat 9y agoRight. And electric motors are more efficient at higher RPMs. At high RPM, the voltage drop due to back-EMF (i.e. actual work) is higher but your voltage drop due to coil resistance is about the same, so you lose proportionally less energy in the form of coil resistance at higher rpm.
- InternetOfStuff 9y ago> electric motors are more efficient at higher RPMs. How big is the difference? It must be pretty substantial to offset both friction losses and gearing efficiency.
- Robotbeat 9y agoGearing and friction losses can be fairly small. Consider that at ~0mph and ~0rpm, producing any kind of torque at all is done with ~0% efficiency, all just resistive losses as the back-EMF is effectively zero. (Note this is no different for an internal combustion engine, although the heat generated is in the clutch or similar such device...) Friction losses don't change much as a proportion of power as you increase speed. For aerodynamic drag, however, your losses do proportionally increase with speed, so "windage" (i.e. drag from spinning parts of the motor) needs to be cleverly reduced by making the rotor aerodynamic if you're planning on operating at high rpm. EDIT: for properly designed electric motors (i.e. thin wire windings, iron core optimized for low eddy current losses), coil resistance usually dominates even at high rpms.
- natecavanaugh 9y agoFor those of us in the US, and vaguely familiar with traditional hot rods, the Chevy big block engine generally came with ~500-700 lb-ft of torque, which in a lead sled, relatively speaking, such as a 60-70s era Camaro or Chevelle would throw your head back and shake your chest like a roller coaster as the car started to slightly drift sideways. 10,000nm in comparison is 7,375lb-ft, which sounds like Harry Potter land in comparison, if all of my conversions and memories serve me. I'm kinda speechless, TBH.
- InternetOfStuff 9y agoLook at my sibling post https://news.ycombinator.com/item?id=15720518 https://news.ycombinator.com/item?id=15720518 700lb-ft is apparently 950Nm. So assuming the same gearing as in the sibling post (very likely a false assumption -- I guess these cars had longer gears), you'd end up with 12.7kNm of torque at the wheels. BTW, if such traditional hot rods had automatic transmissions (they did, didn't they?), the torque converter would have amplified the torque even beyond the numbers I just gave you.
- InternetOfStuff 9y agoYour car has 400Nm at the engine output shaft. After gearing, you'll have the same order of magnitude torque at the wheels as the Tesla. Randomly picked example: Porsche G97/01 (997 Carrera 2 2005-08) First gear total reduction 13.45 (gear 3.91, rack&pinion 3.44) So, ignoring efficiencies, you'd have a first-gear torque of 400Nm * 13.45 = 5380Nm at the wheels. Still "only" half of the Tesla, but not an earth-shattering difference anymore.
- neya 9y agoThank you, now that makes perfect sense :)
- TFortunato 9y agoIsn't the rack-and-pinion for steering, not for power transmission to wheels?
- bkanber 9y agoYes rack and pinion is for steering. Parent may have meant "ring and pinion" which would refer to the differential gear ratio.
- InternetOfStuff 9y agoYes, you're right of course. Thank you. I was wondering, because I seemed to connect the expression with steering as well :-) At least I have the excuse of not being a native speaker.
- adamcccc 9y agoMy car has 1092nm of torque from about 1500rpm and it's mind-boggling... 10,000nm is hard to comprehend and surely more than enough to give the occupants some serious whiplash if not sat properly.