Comments by "geemy" (@geemy9675) on "Engineering Explained"
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.36 sounds hard to achieve with a standard trailer..I think the rear is as important as the front and I found: "Generally, CD values for a semi-trailer truck are ranges from 0.5 to 0.9 depending on the aerodynamic design of the truck." base line is actually 0.8 and 0.5 is achieved only with side fairings hiding all the wheels area and trailer flush with the tractor.
otherwise, numbers are not too far off. its still probably going to have slightly less range than they announced, a bit less payload, more expensive charging (thanks "inflation/wars...").
average maintenance cost should be way better though, as long as the battery's good. but having your truck immobilized for weeks or months because of back ordered part, etc...is not good for businesses. Tesla needs to be on a whole other level regarding repair times, or provide replacement semi during those repairs at least under warranty.
Anyway, it makes way more sense to use batteries for delivery vehicles that travel less miles, at slower speeds, and spend a lot of time accelerating, braking, stopping, idling...they also don't have the same penalty that heavier means less payload, they come in all sorts of sizes and weight so if the truck's 20% heavier, it's not such a big deal. tesla should definitely consider making delivery vans or even people transportation. they don't need megacharger network they'll just charge overnight and will run all day long on a charge
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clever design, but also shows how much simpler is a 4 motor electric powertrain. only 4 moving part, the rotors/half axles, no driveshaft, no differential/LSD, no clutch. wheels can turn at any speed and apply traction control and torque independently. you can do off road, software locked differentials, drift mode, torque vectoring, stability controls, FWD/RWD bias, more precisely and without using the brakes. only downside is you can only apply the power of one motor to any wheel, but thats not really an issue save maybe for extreme drifting where you would want 100% of your peak power directed to the rear
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so if you're driving on cruise control at 80mph on the highway, wheel rpm is about 1000rpm, so the shaft is about 4000 rpm so the clutch will slip at around 4000*0.7%~30rpm and at low load, but it doesn't make sense that the clutch doesn't completely disengage, to reduce wear and fuel consumption? obviously mileage os not concern #1 on a corolla GR, but reliability under heavy use?
I understand it's not going to heat up or wear as fast as a clutch launching the car at 3000+ rpm but still a very odd design to have a clutch slipping 100% of the time. plus a manual transmission only has a big speed difference when starting from a dead stop, when changing gear, speed difference is either minimal (perfect shift) or the clutch slips and the engine speed matches the gearbox after a few tenths of a second. the clutch spends less than 0.7% of the time slipping from a stop to first gear, and it has thermal mass to take the heat, and then cool down when its not used, whereas this will lose power and generate heat continuously. If you hammer a clutch several time in short intervals its going to overheat for sure.
my concern is not only that there's a clutch slipping all the time, but that its also responsible for continuously transferring ~50% of the torque to the rear wheels so not.
Of course if it makes the AWD/handling better, the part is easily serviceable, then OK why not! people who are lucky enough to put their hands on this car wont mind low mpg
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some mentioned the delay that is visible between in the initial footage where the car is stopped and both the steering wheel and the wheel are visible. is it noticeable/annoying when driving? Also you failed to mention variable gear ratio steering has been implemented and abandoned by both Honda (Honda S2000 VGS) and Toyota (Land Cruiser VGRS) in the 2000s ... it would be interesting to see a comparison, to see if they improved the technology, or if it's just making a comeback because it makes more sense in EV's with large screens, yokes, and self driving around the corner. Personally I think it makes sense because:
1 it allows the driver to have a more consistent range of motion at low and high speeds
2 forcing the driver to do 3 full rotations of the steering wheel for three point turns is not great if you can have power steering that allows you to do it without taking your hands off the steering wheel
3 having less sensitive/slower steering at high speeds can be a good thing
but they are concerns though, like
1 the learning curve, is it more dangerous when you're not used to it or someone borrows your car? it could be fixed with settings though
2 how to handle switching frequently between cars with fixed and variable steering.
3 how is muscle memory affected for emergencies, like quick steering adjustments to avoid a car that tries to merge into you, or oversteer/loss of traction
4 how it feels in a long corner with a radius that tightens or widens, to have the ratio change as your speed increases or decreases, and have the steering change with a constant steering wheel input....
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@techno1561 yes in emergency situation in your daily driving abs should perform better because you don't know the exact grip, your tires are most probably not up to optimal temperature, and there's also a high chance that you have slightly different grip on every tire/patch of road, and also that your brake front/rear bias is not perfectly calibrated for the current conditions, so abs will extract the most braking power from each tire. on a track threshold braking makes more sense than on the road because you are doing laps around the same track, you get to test the grip before every corner, the grip is more consistent than on the road, you know exactly were you are going to brake and you can push the limits further and further on every lap, and of course because you are trying to improve your skills in a controlled environment
for emergency braking I'd rather rely on abs giving consistent results, than trying to improving the braking distance marginally in the best case, but risking a longer distance because you didn't get it perfectly right. you don't get the chance to do another lap and try again
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@KennethCherisol yes once your remove the engine and the steering column from the hood, you have a big crumple zone and you can shorten the hod, bring the cab forward, so its big changes
I agree Variable steering is needed for yokes, but could be beneficial to steering wheels too ?
today's steering wheels quite different form those 100years ago there was no power steering, steering wheels where huge and very thin and you needed several full turns to steer , , and cars where more like horse cariage
, steer by wire and variable steering is just another evolution
Future is different, Tesla is rumored to have 4 wheel independent steering in the cybertruck, so yes steer by wire means you can have just one motor on each wheel, no rack, pinon etc. you can have big storage in the frunk and/or shorten the hood. EVs are slowly moving moving to 4 independent motors/suspensions/brakes. everything by wire. it will have a lot of advantages
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@Tosix98 small but powerful! Bugatti did their homework , picking very powerful cells and sizing the battery to be just big enough to achieve the power they wanted, with virtually no impact on weight compared to the chiron and managed to make a NA plugin hybrid with same or even lower weight and 15-20% more power. this is very unique in the hybrid world I can't name a single hybrid, let alone a plugin, that weighs less than it's gas counterpart/predecessor. also smart aero engineering with the massive diffuser, eAWD/driveshaft delete, lower roof/narrower cabin
designing the battery, they did not care about energy but power and weight. this is the only way for a very high performance hybrid or even EV. performance car are not about ramge. the battery density is low but 29C discharge rate is extreme. for comparison, the plaid powertrain is limited by battery output at 7.6C. it's a 5x smaller battery that m achieves 80% of the power. of course, there has to be compromises..
-energy density is 2x lower so the power/weight gain is about x2. that's still a 200kg weight saving. electric range is compromised but who cares.
-the second compromise is like for any hybrid with powerful electric motors, the sustained power output once the battery is drained you have lost 45% power. if 250 is about the speed that can be achieved on gas alone with 1000hp, driving any speed over 250 will start draining the battery. the faster you drive the faster battery drains. this is probably one of the reason why the limited the top speed. 1000hp @250moh means 1350hp at 276mph/445kph
this means about a capacity of a little under 5 min of top speed if the battery was full and depleted to 0%. this is actually not so bad when you consider a chiron would drains it's tank in 10- 15 min at that speed anyway.
realistically, no road or track exist to achieve this anyway.
they have gone to a (base) chiron that can go 260 for 10 min at best to a tourbillon that can go ~280 for 5 min then 250 for another. this doesn't even have an impact on a cannonball race, even the most reckless driver won't be able to drain the battery
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@ctbrahmstedt a smaller , forced induction engine with wide powerband and similar power to a larger diesel engine doesn't need 50 gears to haul. actually it doesn't even need more gears if it has similarly shaped torque curve. what's important is the ability to make high power (let's say > 70% of peak power for instance) at low rpms (ex 50% of redline) . the actual torque value and roms don't matter it's the ratios that do. with a wide power band you can do with 5 or 6 speeds no problem. the reason why modern cars, even turbocharged, have more and more gears is EPA emissions/mpg ratings and the need to have super tall gearing for highway cruising, and be able to run at the most efficient rpm at any speed. super tall gears are pointless for towing anyway.
when you start factoring in towing reliability, you also need your engine that can put out high loads for long periods without overheating or high wear. this can be done on smaller engine. just look at some small japanese engines that are built with such high reliability standards they can run at high loads reliably even after being tuned (properly). but then you also need to consider transmission cooling, so I'm the end you just can't find a complete off the shelf package with smaller gas engine truck that can tow heavy loads for hundreds thousand miles reliably and if you need it you just go for a dedicated big diesel hauler
but let's say you haul once year, you can use any engine that will maintain safe speeds within safe operating condition of the engine
the miles will generate maybe double or triple the wear compared to just cruising, but that's what engines are meant to do
on the end, it's power, not torque, that says if you can accelerate and move a heavy load at a certain speed.
you can generate lot of torque with your arms using a big wrench, or legs on a bicycle, but it doesn't mean you can tow anything
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@madangel71 yes two engines with same power are able to push the same vehicle to same top speed with appropriate gearing.
top speed = speed where drag equals power.
except if one engine is so much bigger than the other that it has to stick out of the hood., increasing the drag. or so much heavier it increases friction drag considerably. but top speed on a flat road doesn't really depend on weight. its almost 99% aero drag vs power (talking about cars with top speeds at least above legal speeds)
acceleration is impacted by weight though so heavier engine with same power = less acceleration. then you have other factor coming in, number of gears, powerband, close ratio gearbox or not, shift delay, etc
but at any given moment, beetween two cars of same weight and aero, going the same speed, it's the one putting more power that is going to accelerate more. not the one with more engine torque. because more engine power translate translate to more wheel torque. but usually, everything else being equal, same peak power and higher peak torque value is still correlated with wider power curve, and thus better performance (especially daily / road driving, not at full throttle/peak power)
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at 1.4g, first foot is done in 0.21s
Also....you're comparing 0-60 on a drag strip, vs 60-0 on road surface...I'm pretty sure with similar grip, the braking distance would be significantly shorter, because air resistance slows down acceleration, and helps braking, and sticky drag strip want to "hold you back" too. it would be interesting to see improvement in ABS technology (meaning ABS that doesnt suck), using direct electric motors brakes actuation, instead of hydraulics, very fast 1ms feedback, and some improved algorithm inspired by threshold braking, to keep wheel lock as low as possible while still constantly hunting down for additional grip
The crazy thing about the mcmurtry speirling is how quickly it comes to a stop when it spins out with the fans working.
of course you need to put an insane amount of G's to do it, but even then, it stops on a dime even going completely sideways.
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fake shifter and clutch doesn't work from a pure performance point of vue but if you are a human driver, not an AI and maybe can't control the accelerator pedal with 1% precision, shifts are useful also on a track as a way to limit your torque below the point you would be losing traction, or precisely adjust your engine braking. discreet gears give you reference points like downshifting in a breaking zone, knowing in what gear you are in a corner gives you a better sense of speed, shifting/short shifting out of a corner with low grip, where a classic EV control with a single speed gives you only one way to control power with your right foot. but considering those EV's with lot of advanced electronics/traction control/torque vectoring can probably do it better than you.
but if you are considering a more analog experience with esp disabled, it can make some sense. same for dirt bike riders who say that on electric dirt bikes they are missing their clutch lever that gives them an additional way to control power out of a corner or in technical Enduro/trial, less sensitive to shocks/vibration than twisting a throttle. from a more daily driving perspective, gears are also an additional input that allow you to control the sportiness/ smoothness compromise as well as the amount of engine braking/Regen. like an instant chill/normal/sport switch . by limiting the max power or Max Regen, you also give more precise control to the driver. but then in this scenario you don't really need to fake a redline.
another situation where I like to use a manual mode wether it's on a stick(duh)/dct/auto/CVT in mountains when you have long down hills as an easy way to control your speed without the need to be always on the brake pedal. you can always find a gear in the straight that will maintain a speed close to your desired speed with no foot on the pedals while still letting you break/accelerate. strong one foot Regen like on Tesla's will slow you down, cruise control will deactivate when you accelerate or brake.
So basically even though cars are becoming smarter and smarter, taking over more and more of your work, controls are getting simpler too, sometimes "too" simple (one foot driving) and at the same time remove some of your control. for instance one pedal controlling -75kW to +760kW is not something you always want to have when you are just driving in traffic. less controls is ok if you want to give away driving to a self driving car.
that being said, my 500e which has only 111hp, strong Regen braking linked to the brake pedal, and zero driving mode/Regen setting, and a single speed, works perfectly for me a daily driver that can easily be driven smoothly or hard. single speed direct drive is for me the closest to a manual transmission in the sense that it gives a direct connection between the accelerator pedal and the motor. as much as I don't like auto transmissions, I don't miss my clutch pedal at all
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tesla semi makes sense but tesla postal/delivery vans, public/school busses, work trucks would make more sense because they have consistent daily routes, spend way more time accelerating/ braking, stopping, idling, etc and also drive at lower average speed, so for these reasons they are very well suited to BEVs, and its pretty easy to make them in different ranges, and order a vehicle that will be able to do its typical daily route within 20-80% SOC, and only charge slowly at night. with this pattern you can extend the battery lifetime considerably.
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@acsmars yeah I agree redefining weight/efficiency/cost/even performance.
they are not the first ones to make 3 wheelers to avoid car legislation
about the cost I think they just sell at a loss.
the problem is what people want safety comfort, practicality, biggest sellers are trucks and SUVs, aptera is a 3 wheeler not subject to car safety, with the interior of a sports car, but the footprint of a truck/SUV I'm still questioning their ability to make a car that is half as heavy, cheaper than as the competition, and safe. light and safe exist but its expensive for instance a Formula 1 cockpit.
if they live up to the announcements about submitting to independent safety ranking, safe handling is confimed, then all they have to do is make a car more inline with public expectation, but keep as much lightness/efficiency as possible
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@bendriver1127 it's changing though. automatics are getting more popular even in Europe, its not only for old people anymore like it used to be. they went from slower, less efficient, more expensive, to in many cases quicker, more efficient, and with DCT being the only option on all the most track focused sports cars, automatics being usable in manual mode.
3 pedal is now more question of personal preference but also German manufacturer are transitioning towards 100% automatic, Toyota is selling 75% hybrids in Europe which are all automatics eCVTs, without even a manual mode, and all supercars are now automatics
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cvt makes sense in purely performance perspective. like launching the car from 0-60 or through quarter miles being always at top power rpm, and no power drop through the whole acceleration. reliability is a concern though for a car meant to be driven hard.
lack of rev changes and constant droning sound really don't go with what we expect from performance car. you could tune software to simulate a 10+ speed transmission by changing gear ratio by small increments instead of continuously. this would have minimal effect on performance if mated to a turbo engine with a very flat power curve and sound much more sporty.
although I've always driven manual until recently, where I've been driving an automatic suv and single speed EV, I still love manual but I can see why it's slowly disappearing. automatic are now better at both pure performance or efficiency, I like how I can put a manual in the correct gear before even accelerating or braking,but with regen available on hybrids and evs, instant torque of evs or wide power curve of turbo engines, and also average cars being much more powerful than a few decades ago, advantages of manuals are getting thinner, and drawbacks are increasing.
from a pure performance/track perspective, I'm even wondering if there is really a single advantage of manual, other than making it easier to know in which gear you are at anytime
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maybe tesla semi will be able to gain significant time thanks to better performance and regen ? easier to pass slow vehicles, quicker to accelerate in stop and go traffic, and better brakes thanks to regen, so you dont have to keep as much distance with the vehicles in front, so it could maintain a similar average speed while cruising a few mph slower. it seems tesla went full on efficiency with the two disconnectable motors. they probably also have different gearing to allow always sending torque to the motor(s) in the best rpm range ? I wouldn't be surprised if the hummer EV with a (max rated) large 7500 pounds trailer is barely more efficient (if any) than an 82k lbs loaded semi...it only got .9kWh/mile with a 5000lbs trailer and 1.52kWh at 75mph with a 6000lbs camper...
I am sure tesla semi driver will quickly learn how to optimize the cruising speed/ charging stops to get as quickly as possible to their destination. most probably they will go faster whenever they have partial load or a drive shorter than 500miles, and otherwise will findn out the quickest way to travel long distance. provided you have v4/megacharger on your route, probably drive according to speed limits/ flow of traffic, drain the battery below 5-10% and make use of the fastest charging that happens at low SoC (at least on all current) tesla models, and leave as soon as the have enough range or as soon as charging slows down significantly
BTW lot of semis don't always follow speed limits, if you drive the speed limit you'll have a fair amount of semis passing you, which is a good reason not to follow the speed limits....
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one of the least documented and discussed subject about battery longevity is age. because how recently have EV become mainstream, studies focus on degradation after 100k, 200k miles. but average EV is driven 10k per year meaning these would be only reached after 10-20 years.
interestingly this means also the average EV who's has 270 miles range and driven only 27 miles a day is used only 10% charge daily meaning there's a strong disconnect between what people is the range they need (often around 400-600 miles in polls) and what they are actually driving. very long trips are more about miles charge per minute than range, and most EVs are underused
there is little info on degradation coming from age, although it depends a lot on what SoC the battery is stored, temperature, a common number is 15 years, meaning no matter how those EVs are going to get charged, the actual number of cycles will likely be around 500 cycles, way below the theoretical limit, because of how little they get driven and the fact the people buy EVs with TOO MUCH range will impact degradation way more than fast charging. it would be nice to see a video about that 👍
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it looks like there are great opportunities to improve batteries life through software.
- battery run in/break in period
- optimization of fast charging
- fixing/repairing/healing spreading dendrites with ultra low current charging/high temp
-detecting ev stored for extensive time soent at low or high SoC. battery could self discharge into a two way charger, if impossible ,slowly drain rhe battery through heating/ac to a safe level, send you notifications about low SoC, or use solar panels to trickle charge out of danger zone(0-5%)
-smart charger storing battery at 50% for long periods of inactivity
a lot of these improvements could be done automatically/transparently , when plugged in, or no, to a ac or dc charger, and your planned yearly battery maintenance could be just keeping your car plugged to your home charger for 12 or 24 hours, or maybe go to a special self service diagnostic and maintenance fast charger for an hour while youre having lunch. I would definitely do it if it was possible. battery dont REQUIRE maintenance but if you can extend life, why not do it. makes a lot of sense wether you're owning rhe car for 200-300k miles, want to increase resale value, or you could even get a bonus for lease returns upon achieving above average battery health.
Ive been trying smartphone charging to 80% for 5 years, still gets me about a day of use on a 80% charge, battery degradation after a year and over 250 cycles is negligible around 0-1%
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as evs become more and nore mainstream people will have to understand them better. I know some just don't want to for various reasons but ev transition will happen sooner or later wether you like it or not. its up to you if you want to stay on the side of people who dont have a clue, and will wear their batteries quicker from bad usage, or have a decent understanding of how they work at least at a surface level, and how too make an EV last 2-3x longer. Many people fear EVs for expensive battery repairs which is totally understandable but what if you can extend the battery life by a big factor by just following some common sense rules. same people who say they dont want to worry about a battery and just drive their car will also take their car for regular maintenance, oil changes, brake pads or even DIY it, do emissions testing, warm up their engine longer in winter, put quality gas, etc
taking proper care of an EV is actually easier than of an ICE and also better BMS software and ev computer could easily give people who dont have the knowledge some guidance. like highlight when you keeo ev at 100% without using it, when you're fast charging over 80%/in hot weather without a need gor it (like not using the fast charge right away). you could have reminders inn your car or phone and progressively learn these rules so that later you dont zven have to think about it
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depends if you're talking about emergency braking, for your safety, or braking that you can plan like for a corner, on the road or on a track. on the road, braking distance should only matter for emergncy braking, there is no reason to brake with 100% power before a corner. Unless you have some carbon ceramic brakes that need to get up to temperature, you always want to stay within a certain safety margin (lets say20-50% depending on people/cars) and keep that margin for emergencies. Emergency, by definition, doesn't warn you before hand so you have to take into account the time to ramp up the braking power, and weight transfer. Interessingly Fortnine did a vide oabout ABS on motorcycle, and how slamming the brakes with ABS does get longer braking distance not only because of the wheels locking up, but because also because weight transfer takes time to settle. its not only about weight, but suspension tuning
On a track, you want to have fade resistant brakes and use close to 100%, but you can anticipate and setup the weight transfer before slamming the brakes. here weight naes a difference in the long run because after dozens of high speed braking, the heavier car is way more likely to overheat the brakes
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@superfluous9726 even 20hp which is about the power on a highly tuned sur Ron, on a bike would be impossible to use without wheeling, riping the chain, destroying the wheel, etc
basically the whole bike/motorcycle has to be designed around the power/torque/speed and wouldn't be very different than current evikes or electric motorcycles.then once you account for the battery weight that is maybe at least 60/70% of the power rain weight, the gain is not that big.
then you also have to consider the gear reduction fora 10krpm motor going for instance 50mph top speed, you need around 1:20 gear reduction and the gearing starts to be heavier than the motor itself.
there is still potential for high power density motor in ebikes, because if you have "too much" power, you can limit it electronically and have a nice wide flat powerband so that your bike can handle super steep hills with high torque or go flat out 50mph with high rpm, all on a single gear, with a mid drive motor and a heavy duty chain and you are left with a few options for the pedal drive, either a classic wide ratio bicycle chain + derailleur or a more simple generator to do torque sensing and force feedback, and no mechanical link, or no pedal at all and just an electric motorcycle
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@Factory400 ideally yes but have you ever seen an engine weight being measured with all it's accessories including ECU wire harness, fuel pump, fuel tank filled with gas, fuel lines, radiator,fan, cooling lines, air box, exhaust, cat etc....
electric wipes the floor of combustion with power density, but gas still wins hands down energy density so overall as long as you need long range/fast charging electric is heavier but electric power density makes it much easier to make muscle/performance versions of road EVs, while maintaining efficiency, weight and reliability constant, at a cheap cost. just slap more motors. this means we are actually going to get properly quick EVs (in the 3-4s) with 500+HP that are also good daily drivers and people can afford like model 3/Y Performance, EV6 GT Ioniq 5 N, Volvo EX30. these are not cheap but still ownership cost is way lower than any AMG/M Power/or even american hellcat/mustang GT
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"if you think about what is ideal with the torque curve basically you just want it to be as wide as possible and as flat as possible" (just like your mom?)
this is only thinking with combustion engine mindset.
from a perfocmance point of view and for similar peak power, the perfect POWER curve would be a flat one, so torque curve would be a hyperbola 😉
of course your torque cannot be infinite, and below a certain speed, increasing torque above a certain level gives zero performance advantage and will only break parts more quickly or require to overbuild them, so you have to limit to a max value.
this is pretty much the tesla Plaid perfect power/torque curve.
as much constant torque as tires cam manage from 0-60, then as much constant power as the battery can deliver and the cooling system handle, from 60 to 200mph
..but even with a combustion engine, flat power curve means you don't need gears, or only a few of them, to maintain maximum sustained acceleration. Now if you introduce another parameter which is cruising efficiency, you're going back to transmissions with a lot of speeds (8-10), just for the sake of being able to run the engine with optimal gearing for efficiency, at any cruising speed.
of course in real world you have rpm limited by piston/valves/conrod/camshaft, and torque limited by displacement and max boost, and engine/gearbox internals, so you want to combine both with maintaining max torque as much as possible across the rpm range, and because the power is only limited by fuel pump/injectors, you can always increase them to get rid of the power cap, which is easier than increasing displacement, boost, or rpms
But you think outside the box and consider CVTs....the best torque curve is ANY torque curve ^^ as long as you have good efficiency at medium/low load/rpm and good power at high rpm/load
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@vl3005 there are a few parameters that can impact the acceleration curve.
- the demon uses a clutch which can be both a disadvantage because it's harder to do consistent perfect launches even with launch control, and clutch will overheat after a very hard launch, but it also means the engine and flywheel are storing rotational energy that can be released almost instantly at launch. usually more an advantage for EV with AWD and good launch control but it seems here with perfect conditions the demon 170 launched even harder than anything else
-the demon can hit 60 in first gear so there is no gear shift delay or power loss in the 0-60. with proper tire temperature and surface, and good launch control, it can be constantly at the very limit of tire grip from 0 to 60 hence the amazing 0-60. during the quarter mile it will need to shift 4 times to reach ~150 so each time you have interruption in power, qnd power loss after the shift with lower rpm (demon doesn't have a flat power and) so the plaid could gain maybe around 0.1s for each shift
-demon has higher power to weight ratio so when it's right at peak power, and putting down all the power to the ground it has higher peak Gs than the plaid.but in average very slightly lower.
- as speed increases above 60mph, and the demon shifts gears, and the plaid loses torque, acceleration slows down, and air resistance increases. the weight becomes less and less important, and air drag becomes more important. this is why the plaid wins at higher speeds because much better coefficient 0.208 vs 0.37, the demon has almost 90% more drag !
1/2 mile would probably be won by the plaid (only if unlocked to 200mph)
so the plaid with same horsepower has the potential to have 23% higher top speed.
a 840hp demon did 211,1025hp could do at least 225 and an Tesla plaid could do 277... so a demon getting close to 200 Would be accelerating very slowly (70% pushing air, 30% accelerating) whereas a plaid doing 200 Would would be doing more like 30% pushing air , 70% accelerating.
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