Power vs Torque - In Depth Explanation and Mythbusting!
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- เผยแพร่เมื่อ 20 พ.ค. 2024
- Today, we are looking at Power, Torque and the arguments on the internet over them. I'm not the first person to cover power vs. torque, but I'd like to think this is the most comprehensive video explanation out there.
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Best video on the internet about power and torque. Detailed explanation from an engineering point of view. - Engg. Student
How come your videos get so little views? You are a gold mine of information I hope other viewers realize it!
Because the only people that care about this level of detail are racers, and I'm trying to beat my friends into oblivion...so I don't always share. Lol
If any body tries explaining torque and horsepower like, "torque is how hard you accelerate and power is top speed" or "power is how fast you hit the wall and torque is how far you bring the wall with you", they have absolutely no grasp of the simple concepts of torque and power. I have not yet seen someone who has set the torque vs power thing straight until this video Kyle. Good to know some people aren't completely clueless.
True. The formula makes it very clear. That's because people see torque and hp as 2 separate quantities describing the same thing (they are NOT). Torque x rpm is what is important. If you take the effects of gearing, wheel size and all those other variables, then the final equation will show that HP vs rpm is what matters for overall performance of 2 vehicles with everything else equal but the power curves.
Lets assume we have Car A with 100 lb-ft and 50HP and Car B with 50 lb-ft and 100 HP. Both of them race with point a to b (500 meters) on a flat surface and other race on a to b (500 meters with flat surface of 250 meters and another half 250 meters with elevation of 45 degree angle. Which car will win in 2nd race with 45 degree angle?
Rauley Shar more power always faster period
Prove it! That question only be answered after doing the experiment, but i guarantee you that 99.99% will have that question answered wrong.
Rauley Shar more power, reduce gear ratio, twice the torque to the wheels at same speed, power wins
If anyone uses the "power is how fast you hit the wall, torque is how far you take the wall with you" line again after this I don't even know what I'll do...
Enjoy the video!
KYLE.DRIVES velocity is how fast you hit the wall, conservation of momentum minus frictional forces is how far you take the wall with you.
Mass has to be involved in there somewhere.
I hate that line
+idontcare80 It's involved in roughly figuring quickly you could accelerate given a certain amount of power
wonderful video, expecially the explanation on rally engines and gearing and the considerations on rotating parts in various kinds of engines
Nicely done! I have been watching a bunch of these "Power vs. Torque" videos and this is the best, by far!
The thing about torque and HP is that torque must always be taken together with engine speed (rpm) to make sense -- it is this COMBINATION that tells you HOW the horsepower is delivered. So if you see the formula, either you can choose more acceleration at low rpm (a tractor engine) or less acceleration but higher rpm (a motorcycle engine). That's why gears were invented -- we didn't have enough torque at low speed at the wheel and that's why a hybrid Koenigsegg Regera used electric motors to get rid of the gearbox.
Gearing can take 2 different engines with same HP and make them perform similarly on the same car provided their torque curves look similar because the combination of wheel speed and wheel torque is what matters.
If the rpm is the same, the engine with higher torque is producing proportionately more horsepower and this is why diesels feel "torquey" -- it is simply more torque and therefore more HP available at lower speed compared to a petrol engine (assuming similar gearing) and why petrol engines rev higher.
A HP vs rpm curve is good for comparing 2 engines, but a torque vs rpm will tell you how that engine will behave over the rev band.
Thank you! This is the video I was looking for. Connects power and torque to acceleration and gear ratios.
I'm gonna link this video each time the question arises. Perfect explanation!
Just found the channel - not that it says anything very new to me (except the interesting insights in fluid dynamics/aeordynamics, which I only know very superficially) being a math/physics major, but it's very nice to see material out here that actually tries to voice information that can actually be proven.
Most YT/FB "knowledge" today seems to be based on the misconception many people seem to grow up with now: That when many people say the same thing very loudly, it is inherently true. No matter how wildly incorrect they are.
Best explanation I have ever seen so far! Good Videos, Keep going!
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Awesome mate - please keep these videos up - very much appreciated :)
Kyle, beautiful explanation! You're right that the vast majority cannot get this concept right, and it makes me feel so much better to see someone who gets it!
If I may offer very slight suggestion, I would say that what's under the torque curve is meaningful and represents the power that is produced. It's torque (y-axis) * rpm(x-axis), and as we know torque * RPM is power. What's under the power curve is not meaningful (hp*rpm or tq*rpm^2/5252).
I've been trying to explain this to people for years. Thanks for taking the trouble to make this video.
The best video i have seen in this topic, thank you
Brilliant explanation! Was thinking for years of doing one like this since there is so much confusion around.
P.S. Motorsport engineer too ;)
Thank you for this video. Yes, teachers must be patient. From the comments below, it seems most people didn't go to school or they forgot what they learned in high school:
TORQUE is a FORCE (rotational in nature, also called moment). (N.m).
Forces produce WORK or ENERGY (J).
POWER is a measure of the rate of production of Energy (J/s or W).
Excellent video!! I'll be directing allot of people your way:) I have two videos on the subject of power and torque, and for those who really want to get it, I love the challenge of figuring out where those deep rooted misconceptions lie through a threads of carefully written replies.
This is another of the few power and torque videos out there that use correct conceptual presentation, precise language, and still presents the concept in a concise and unintimidating way!! Thanks for making the internet a better place:)
Im constantly visualising a slow speed marine two-stroke diesel engine, because those are the engines i work with. They are the definition of a torquy engine, the sensor for torque is showing a value in kNm (at high load in the upper 3 figures). That’s the reason why they don’t need any transmission i guess.
Very nice explanation!
Thanks a lot Kyle..very good explanation 💕
That helps out a lot. Thanks man!
Very good explanation.
If you want to see this in action, tfl truck did one of their Ike gauntlet tests with a pair of titan XDs, one with the gas and one with the Diesel engine. The gas engine was considerably faster. Diesel engines being good for towing has more to do with longevity and fuel efficiency than torque being better for towing.
Torquey engines are also good for off-road, like tight trail with obstacles off road, because it allows you to avoid having to cut power to shift if you're climbing a steep hill, for example.
And that's why you have to clutch a lot with a wr250r - to keep it in it's high power band, yet it is often compared head to head with a DRZ400, with it's tractor factor torquey engine. Because it spins fast, the WR manages to compete with a much larger engine.
To drag a load from a stop with a high rpm engine is going to burn a lot of clutch until speed matches. Once up, you could pull that load, but high loading an engine for prolonged periods at high rev's is exactly the type of thing that tends to wear them out or break them quickly.
And the flat curves helps the diesel for not needing to shift, where a gasoline would need to rapidly shift down if it got off it's power band.
Thanks for posting
No dislikes! That's the best proof of good quality. Well done!
75 dislikes in 2022
Thanks. Could've used this video years ago when I was still in the mood to battle idiots on the internet. Another thing I like to mention during this is that Power is the Rate of Energy Transfer. Anyway, well explained video and thank you. If this comes up again, I can just copypasta the link to this video.
I think the underlying issue is functional gear reduction. Ever corner is not the same, as a gear selection for one corner may, and often does not, work for another. In the ideal situation each gear ratio is properly selected for each corner providing optimal power out of the corner. In reality most people are limited to five or six gears and only have the option of changing their final drive ratio as it is the easiest gear to access. Since the other option is to strip down the transmission and have it re-geared. This is not ideal for the average car owner. Now a car with tall gear ratios and enough torque to pull across the rev range has more functional use through corners of various radiuses (radii?); where as a car with close gear ratios has less functional use since the corner radius must fall within the functional range of each gear. This really shows the advantage of CVTs since they keep the engine at peak performance with the optimal gear ratio. Again I will reiterate, having optimized gear ratios for specific corners provides the best performance, but is not always available in practice.
Very, very, very good. Congrats.
Great vid mate
Awesome vid. they just introduced this at my uni so the timing couldnt be beter :D
i would really like an aerodynamical analysis on the lamborghini special models (Veneno, Sesto Elemento, Centenario) because lamborghini haven't released any downforce/drag numbers for them
WOW. Loved this. I always thought of it as: when you accelerate, you are giving your car energy. The time it takes to give your car energy is called power. But I had no clue how that relates to the force being applied at the wheels. Your graphs of the power vs torque curves, plus how a power limiter affects what shifting does.. Amazing!
I would love to say that this should convert people over to CVT's.. but the droning.... CVT's should be trained to stay at the top part of the power curve, but be wider so that a sense of acceleration (rpms increasing) and shifting can be felt.
energy:time =power energy:distance =force if you increase power 5 times at the same velocity force increase 5 times so power vs force=linear dependences = watt:m/s=newtons.
@@mociczyczki Agreed - however Torque is the per revolution number and does go down in most cases, while power is without regard to revolutions. So yes, at a given RPM, Power and Torque are linearly related. But as you increase or decrease your RPM's what power does vs what torque does is different.
@@pureabsolute4618 torque is force x arm lenght ,power is torque x rpm power is energy :time torque is bullsh.t x crap of sh.t 👌🏻no idea what you try to say 👍🏻
Let's note that the bigger vs smaller motor battle isn't really about overall power. It's really about 2 things, how long a motor will last at a given power level. And how does if feel as you're going through the gears. V8 guys want the power soon and go long and they want reliability. The smaller engine guys will wait for the quick hit at the top and save the weight...unless they're boosted, and that goes back to (reliability vs HP) concerns that a bigger engine guy doesn't want to deal with...
This is the best explainer of this concept I've seen so far - the diagrams of the "torquey" and "powerful" engines really helped.
I think the guy for engineering explained did a better job with it, he takes you through the math a little slower. Both of them are good though.
Could u compare HP & Torque specs on different automobiles of the same grade? For example compare 4 cylinder Honda Accord with Toyota Camry? And show their performance with respect HP & Torque? Also how does the transmission plays its role to give higher torque at the highest HP?
Is it needed to have a higher torque at lower RPM’s when the HP is lower?
I always knew this and always tried to explain this to anyone just like you did, so I agree with everything you said in this video. The only thing you didn't mention is that maximum power is often achieved at high RPMs, and to get to high RPMs it requires a certain bit of time, so ideally it would be better to have maximum power at the lowest RPM possible. In fact it is possible that in a drag race between two cars in which one has higher power at high rpms and the other has lower power but at lower rpms, the second car may win, because if the first car has too much inertia in its drivetrain, it will be slower to reach its maximum power... time is an essential variable to consider when evaluating power curves ;-)
I know nothing about drag racing (I'm into motorbikes) but presume drag cars have clutches? So the driver of a high speed, high performance motor vehicle will have to slip the clutch a lot more than a lower speed engine. Energy will then be lost as heat and the clutch may burn out. So practically speaking, it is not as simple as the presenter has made out. High engine horsepower is one thing, delivering it as torque at the wheels throughout a race, is another.
@@60sfanatic yeah the assumption is that you have infinite gears and 0 delay between gears. Low end power (aka "torque") is better for launching off the line if you don't want to destroy the car. Hence the dominance of evs.
But also, drag racers tend to be tuned closer to the "dyno queen" curve with big, peaky turbos rather than low end torque because they can have things like anti-lag. So real drag racing is not the best representative for torquey engines. Street racers and haulers are more likely to benefit.
Great stuff.
Great Video Buddy, Wishes from India!
As a mechanical engineer and motorsport enthusiast, it's refreshing to see someone actually explain these correctly.
*I showed my MX friend this concept when comparing bikes so he could see why peaky engines tended to be faster.*
To explain, I made a 'detuned for equivalent rpm curve' where we took the same bike frame & transmission, but threw the peaky engine in there with a gear reducer to make it equivalent rpm as the original torquey engine.
*Those peaky engines didn't just have a little bit more power, they dominated with something like a 25-40% higher torque and also tended to benefit from hanging on to gears longer, which means staying in a better gear aka multiplier longer.*
I'd add 1 more tidbit: when talking to people about torque and gear ratios, you end up with the logical pondering of "wouldn't it be nice to have some way quantify how good torque is by the ability to gear down torque from a particular speed/rpm?" *And that's exactly what power does.*
Power tells us how 'strong' a motor is so we can relate it to performing actual work (such as accelerating), without having to 1st know what it's being used for.
You can take a motor of a particular power at a particular rpm, and you can gear that back and forth however you want. (aside from losses) You get that same power out of whatever gearing you do. Your gearbox can 1/2x the speed and double the torque, or it can double the speed and halve the torque, but the power comes out the same - because that's related to the strength of the motor not the gearbox.
This is the classic comparison of a windmill to a Ferrari engine. The windmill has more torque... moving very slowly, low power. Re-gearing that windmill power will never make a fast car.
The Ferrari has much lower torque but loads of power. If you geared it down to as slow as the windmill, you'd have enough torque to rip the whole windmill loose and spin it around.
yup 👌🏻 but still more torque down low less power at peak is more daily friendly characteristic 👌🏻
@@mociczyczki I consider that solidly into the preference category.
I tend to prefer high reving engines (eg JP). Some people love torquey engines (eg big block American).
They both drive differently with style of driving preference being a far bigger factor vs 'better'.
My revy ninja 300 and torquey dr650 are almost identical weight bikes. The DR's torque makes it not want to go below a certain speed and it doesn't really tell you by feel that you are changing speed. It's easy to accidentally go 25mph instead of 15 or 35 instead of 25. And I have to watch taking off much more if there is silty gravel, because it has torque on tap to overcome that traction easily.
My revy ninja by comparison is _way more fun to ride_ on the street and _way more forgiving._
The smoothness of the engine and smooth rise into power makes it easy to take off slow and smooth (silty gravel) or burn the clutch a little and keep it on the edge of grip. The engine gains power as it accelerates, which works well, because the faster you go the more power you need to gain more speed.
If it were not for the balance of the bikes, the ninja would be way safer to ride on ice, because it both has a higher allowable rpm (not forced to shift) and taking off and cruising rpm are both lower power/less likely to slip by overcoming traction.
As with cars, in twisty roads, high rpm gives excellent power and throttle response, which enhances how fun it is to take those well.
That said, a lot of people prefer big blocks with torque, which is great for lossy automatic transmissions, for that instant whump of power at cruising rpm, and for what I would consider easy lazy driving, vs spirited driving.
Most of the people I know who prefer that are not the type to enjoy nuance of the throttle. They want to wamp it and burn the tires/impress their friends.
As a final note, that 300 gets almost as much power as a 650 and gets significantly better gas mileage. Similar for cars.
And there is the consideration of budget cars with small engines: a tiny (low cc) torque tuned engine is always gutless. A tiny high rpm engine _may_ be gutless down low, but reach into 'zippy' up high and feel like a much better little car for it.
@@andrewstambaugh8030 yea for most avg driver i forget mention 👌🏻
nice explaination bro....keep it up...love from
india
I have a lot of bhp, torque curves, I don't know which one will better suit for me as in engine is going to be used in
fsae cars
That last bit explains why my car feels gutless in high rpms and barely accelerates faster than it would at the same speeds in 1 or even 2 gears higher.
My car has very tame camshafts and a tiny turbo, so it produces a nice amount of torque around 2k rpm which holds up to about 3.5k rpm before rapidly decreasing, but despite power "peaks" at 5k rpm and the engine revs to 6.3k rpm, I only go over 4k rpm when upshifting earlier would cause extra shifting (before a corner) or be dangerous (mid-corner), and I often shift up 2 gears when I do eventually upshift much over 4k rpm.
It does feel very strange, almost like there's something wrong, but because most of the power is already available at medium-low rpm it is actually quicker than my previous car with a bigger NA engine that had significantly better peak power/weight but couldn't get out of its own way below 3k rpm and was only happy close to its 7.5k rpm redline.
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The COMBINATION of torque and rpm is what actually means anything, because this tells you HOW the Horsepower is delivered. Similarly HP vs rpm is good for comparing 2 engines, all other things being equal.
Given the same engine rpm, gearbox and vehicle, the engine that produces more torque at x rpm is also producing proportionately more power at x rpm and will accelerate harder. That's what it means when people say that an engine is "torquey". That's all there is to it.
I have a question I would like to ask.is there any benefit to having either a high or low torque to weight ratio or is that a thing.i know there is a power to weight ratio but is measuring how much torque there is to move the car vs it's weight beneficial to know
power to weight ratio is a more relevant thing to know, so why bother with the half-measure?
Great video! I would of like to see more of the difference between the two outside of speed. For instance, hauling a heavy load with a high horse power/rpm engine is a nightmare up a hill. Like the Detroit 2 Stroke Diesel was. You got a new sub from me though!
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It would be fine if you were in the right gear before you started, but once you drop off that power curve, your power plummets.
Wow that was a bang on explanation!!! But I'd like to know what a differential does here. Does it split power or does it split torque between the rear wheels? Cheers!!!
Pranav Adhith it splits torque, which in turn means it splits power as well because more torque at relatively the same rpm=more power.
A standard "open" differential is actually splitting the torque from the input shaft equally to the two output shafts at all times (give or take a tiny bit due to internal friction). It does however allow the rotational speed to vary, for example when one wheel looses traction, thus also splitting the power unevenly. Same torque but at different speeds = different power.
Robert S very true...I was however referring to a situation when there is no wheel slip like in 99% of driving situations.
Now what happens if the same scenario is in an LSD? 😊
maxjtj31 With an open differential it doesn't matter, it will ALWAYS split the torque equally. One big key to this is that torque can be applied without a result, but no power is being delivered until something actually moves.
it be nice to see you explain the right way in picking gear ratios .. like you launch gear 1st on torque? and the rest of gears i between max torque and hp?
No max hp all the way unless you dont have enough traction watt:m/s=force so avg power only count ,torq at crank is pointless.
It'd be nice to see a more direct comparison of different engine types in the same type of vehicle. Like compare the latest GSX-R600, Daytona 675, and SV 650. How gearing affects the horsepower/torque dyno readout (so people who installed different sprockets don't get pissed at the dyno operator because they 'lost' power). I saw the torque change on my Speed Triple when I added three teeth to the rear sprocket. Lost around ten peak horsepower but mid-range torque jumped up due to the shorter gearing.
Explain to them that every time you shift up a gear you lose torque. That's how transmissions and gearing works. If you take a dyno run in 2nd vs 3rd, they still both show you how powerful the engine is.
But it doesn't make sense to try to overlap acceleration in 2nd vs acceleration in 3rd, *because kinetic energy is of velocity squared* (ke=0.5*mass*vel^2), so _accelerating at a higher speed takes more energy_ than accelerating at a lower speed. (that's also telling you why hp determines max speed...)
It would be a lot of work, but you could translate it to equivalent at a different speed... (way too much work, rather than just saying, put the original sprocket back on if you want to see apples to apples).
4:00 - EXACTLY!
Hi Kyle, thanks for this explanation it helped me explain to my friends why they were wrong. Hopefully they cease their inane arguments for a while.
Btw, my car makes roughly 300kw at 3000rpm, 400kw at 4000rpm, 500kw at 5000rpm, 600 kw at 6000rpm carrying through to 600kw at 8500rpm. So for a 600kw car it is very quick, rather than runing a laggier turbo and losing power everywhere to make 750kw up top. I'd rather be a quick 600kw car than a slow 750kw car racing against someone who can hold 750kw the way i can hold 600kw, where as my setup would only peak 750kw and everything before that would be less than I have now essentially.
@@delusion2987Pretty much every gear all the time... do you redline your engine every gear? do you live in a never ending drag race? Your power has to start somewhere, and if it doesnt build gradually you wont get traction. The way your power builds during the rev range will mimic the way it builds when you plant your foot at high rpm. having 100kw at 3-4000rpm and then 500kw at 5000rpm is a car that will just break into wheel spin whenever approaching the 5000rpm mark, one that makes 300 at 3000, 400 at 4000 etc will not break traction (it is also very predictable and doesnt surprise you with a sudden burst of power depending on what rpm you happen to be at). Meaning you can plant your foot at any given time and use all the power available, which is more than the guy next to you if he only makes power at max rpm.
The less manual shifts in a race the better, and you dont come out of a corner at 7000rpm. 1: because thats just causing you to shift on every corner exit and 2: because exiting a corner at full throttle/full boost does not encourage traction and is much slower than pulling out of a corner building up to max torque. That's why race cars have a linear power curve to promote traction and give a wide range of usable power for different situations. My linear power curve just starts earlier than most giving me an advantage at any given rpm and then holding my max power for longer meaning if I am in a drag race before and after every gear change I am at max power and max acceleration, rather than someone who builds for their max power toward redline. That's why if you look at new supercars they are all making massive amounts of low down torque, the day of the laggy supercar is gone and they are twice as fast as they have ever been.
Basically plenty of reasons to have a powercurve like mine with no disadvantages.
@@delusion2987 I always use it when trying to drive quickly, 3000-4000rpm is a very common point in the rev range for roll racing and for circuit, because one gear lower and I'm changing gears on corner exit, and roll racing is starting speed dependant. You can't always have the perfect gearing for every starting speed. Actually my turbo is capable of 750kw, but it's useless to make more top end than I already do. I'm not a drag car. It's diminishing returns, and getting a burst of acceleration right before a braking zone doesn't do me any favours, you end up braking more than you are accelerating and times don't improve at all. There's a balance, and my power doesn't roll over because my turbo is too responsive, I reduce boost and timing top end to control the power to hold a continuous acceleration geforce value I guess you could say. I also limit my boost in 1st and 2nd as traction dictates for launching, autocross or low speed corner purposes. I've spent many hours at the track with professionals setting the car up for optimal conditions on a broad range of circuits, corners and racing categories. I don't run high end aero or slicks, I race as I am as a street car, whether it's 1/4 mile, 1 mile, 1000m, 800m, hill climb, autocross/motorkhana, circuit or roll racing I use the same setup for all events. I don't know of another car in my power range that I don't have power band advantages over, and it shows.
If you want to run more power, like 750kw the same theory still applies, making 750kw for the whole power band vs 600, then 650, then 700 then 750kw as the revs increase is still better. You can always say just add more power is never ending. Find where you want to be and optimize that until you have nothing left to improve.
OK GOT IT THANKS
What a pleasant surprise to see you refer to axle RPM and the "area under the curve." The later is important to\for the following questions. I have some questions to challenge some of your comments. Lets assume we are only referring to rear wheel drive cars. Your explanation suggests that the torque to power relationship at the rear wheel is the same relationship that it is everywhere else in the power train. Is that really true? Or is there a point where the Torque and HP relationship breaks down and they aren't tied together to be equally distributed where they are measured at the rear wheel? If they are not tied together at the rear wheel how are they separately distributed? How is torque distributed through the chassis and suspension if it's all going to the rear wheel? Assume all dynos are created equal if anyone is thinking that is a consideration for these questions but it is important to realize or know how different makes and types of dynos reach the conclusions they do. What information is derived from extrapolated conclusions from peripheral information with programming and isn't an actual, direct measurement?
Related questions; Torque and RPM have an inverse relationship so can this relationship be worked backwards on a dyno'd car from the axle or tire RPM? Why or why not?
Finally, Torque Biasing. The name alone suggests torque can be manipulated. Is that true? How is it done? Along the same lines, what is a torque cancelling chassis? Using your definitions and explanations shouldn't posi-traction, a LSD or similar differential work as a torque multiplier?Some engineering comments. For a physicist torque and a torque moment are the same but that's not true for an engineer or mathematician. Torque is the amount of measured change between torque moments. If there is no change or at equilibrium torque is zero. This conceptual reality is a necessity to anyone designing an engine, suspension or chassis.
thanks sir
at the end, you mentioned that you need to strengthen every combustion to maintain the lower rpm, and the opposite on higher rpm. Does this mean if you cruise at higher rpm will save you gas? since you only need to make a small combustion to maintain the power?
no ecause how much power is reuired depend on drag aero roling resist power lsoeess in dirve train and at higher rpm you have more friction and heat .,at lower rpm you get beteeer milleage you always use as much power as is needed to travel at constant velocity no matter you have 10 k rpm on clock or 2 k rpm diffrenc is that there where engine produce less pwoer you must push pedal deeper results is egzacly the same except like im mention heat /friction at higher rpm eat more fuel :X.
that's one hell of a power band once turbo spooled up
4:50 that's one hell of a turbo lag
is that a 1.6 with a huge turbo?
is Engine optimal speed range a factory setting and can not be changed,for example an engine with 3000 rpm to 4000 rpm optimal speed range or optimal speed range can be changed according to driving conditions and throttle input?
first explain what you mean optimal rpm ? if you mean peak pwoer than yep it setup be manufactury and you cant change it unless you tuning your engine .
I thought power is result of the torque at a certain RPM. high torque in low rpm could mean high power and same thing for low torque high RPM. is the way my understanding correct? power is how fast a work can be done. T• angular velocity or W/t. work is F•d which means greater power faster work is done. At a certain mass and distance acceleration is greater.
Yes, at the same rpm, if one engine produces 100 lb ft of torque and another 200 lb ft, then the 2nd engine is producing double the HP at that rpm as well.
1.FOR 149 cc Pulsar-Max. torque: 12.5 @ 6500 (Nm @ RPM) Max. power: 15.06 @ 9000 (Ps @ RPM) 2. for 349 cc classic R.E- max.torque : 28@ 4,000 (Nm rpm) , max. pow : 19.80 bhp @ 5,250 rpm tells what. what is the basic relation between torque and power.
catalogue peak torqque which they show you at crank is at specific rpm like you write you must calculate power from this relation so such 12,5 Nm at 6500 rpm is around 12 Ps now is simple stuff to do if you want know be how much stronger this pulsar -max be accelerate with you on it at egzacly the same velocity ( this is important you cant comapre both on diffrent vehicle velocity because than it be like comapre 0-100 to 100-200 in 2 diffrent vehicle which is pointless ) at peak power where is 15,06 Ps vs at peak torque where is 12 Ps you must just divide 15,06:12 and you get answer = 1,25 times or something close to this biger force push pulsar forward at 9000 rpm than at 6500 rpm at gezacly the same velocity so you must good choose gear to comapre 6500 rpm to 9000 rpm at similar velocity cant be simplier explain :x .
I felt like I learned a lot more than my puny mind could handle in one go, so I had to watch a second time and loved it
I prefer the automation game's physicist explains the difference much better but I'm liking this channel so far
Can you also make a video how engine load explained
Making it simpler to understand
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I don't know how, but everything That seemed to make sense in my mind actually does in real life!
Does the maximum fuel limit on current Formula 1 PUs function something like a restriction plate? (say same power at 11000 and 15000 rpm) Can you make an educated guess on what current Formula 1 PU power and torque curves look like?
That's a very good and interesting subject which I hope Kyle will pick up. You might think that an F1 powerband is similar to WRC since both are limited with how much fuel they can burn (F1 directly and WRC by the amount of oxygen available), but as Kyle said that WRC cars do that so they don't have to change gears as in F1 it isn't a matter. If you watch F1 onboard telemetry you will see that drivers keep the rpm in a very narrow range and the engines don't rev up even close to the limiter, hence I would say that the manufacturers have designed the engines to operate at given rpm and not really care about the rest of the rpm range. I'm suggesting more like a parabolic powerband with peek at around 11,5K rpm.
Current F1 engine got an "ultra broad" powerband as they are electrical assisted and thermal efficiency are somewhat close to that diesel engine. I think their torque are somewhat linear (ascending) due to zero turbo lag, high thermal efficiency as they running a compression ignition (TJI) system, with no significant power drop at all at the top end due to the pneumatic valve train system (zero valve floating). If the variable valve timing are allowed in F1 (let say they running an infinitely variable valve timing like valvetronic or valvematic), it will be the most efficient petrol engine ever build in history of automobile.
if max torque occurs at 2400 rpm ,then we can get best(at steep hill for example) torque by held the engine at 2400 rpm and put the transmission to first gear......is this right?
No, you will get the best torque at the wheels by shifting to whichever gear gets you the most power. I.e. more engine power at a lower gear pushes harder than more engine torque at a higher gear.
E.g. suppose max torque occurs at 2400 rpm and max power occurs at 4000 rpm, first gear is 4000 rpm at 50 km/h and second gear is 2400 rpm at 50 km/h. Then if you are going at 50 km/h, first gear will get you better torque at the wheels.
@@Trancefreak12 EGZACLY im happy that sometimes im found people who know how it goes :).
good sir
Use this analogy:
TQ = How much you make per hour
RPM = How many Hours you work per week
hp = amount on paycheck/buying power
Which is better... Example
25$/hr (tq) working part time of 15 (rpm) hours a week. = 375$ worth of buying power per week
18$/hr (tq) works full time of 40 hours (rpm) a week = 720$ per week of buying power
What you can see here is several things. 1. Of course you want higher tq when possible, but this is the stress associated with the cylinder walls. 2. rpm is stress in moving the actual rotating mass or dynamic parts within the engine.
This is why there is no such thing to give you a performance estimate on a car by using its TQ / Weight ratio. This number is completely meaningless since you dont know the rpm.
That would be like trying to get a bank loan and telling the loan officer. Can I get a loan of 100K. I make 35$/hour. "how many hours do you work?" Askes the loan officer. "I dont know sir"
LOAN DENIED!!!!!
You cant hold money in your hand just by saying you can work 40 hours a week, nor would you have money by having a job where they pay you 20$/hour but you dont work any hours. None of these would net you a single candy bar. only combined can you move shit, pull shit, accelerate shit or buy shit.
THis is why the fraction.. Power to weight ratio is used. Since hp (buying energy) is what actually moves the car or in our analogy, is what can be used to actually buy things.
Using tq/weight ratio is just as pointless as using rpm/weight ratio to calculate 0-60 or any other performance measurement. None of these fractions would give you any info on performance since they are both literally an incomplete thought.
Now this also explains why engines that Pull things have lots of tq but low rpm. It is less stressful to make 400hp constantly at 2,000rpms, than it is to make 400hp at 8000rpms. It is the same as a human. Would you rather do the same job at 40$/hr and work 10 hours a week, or 10$/hr and 40 hours a week? WE would all say the 40$/hr. same with motors.
So FOR THE LOVE OF GOD!!!!
STOP THIS IGNORANT DEBATE ON TQ vs HP!!!!!!
Torque and power are engine characteristics (graphic). Why you draw as though it depends on the gear?
He was showing the Torque at the wheels...which is dependent on transmission/gears. Basically explaining how an engine with no torque (N/A F1 cars) can be fast.
So it does not mean an increase in RPM is also an increase in torque, since the line drops after reaching a peak torque?
wonderful
I like flat torque curve, because it does not have to rely on a certain engine speed.
Can someone explain how you can get lower hp that tq if your multiplying by 1000-12000??? I feel like this is really obvious, but please help
Can you rephrase that question?
You should never be comparing power numbers to torque numbers. It's nonsense because they are different units. It would be like comparing your height to your credit score.
200*2000/5252=76 so 200 being torque and 2000 being RPM divided by 5252=76hp. Hope thats what you were asking about
Problem Child AKA The Truth only when using lb-ft for torque, which most of the world doesn't.
Finally someone that understand that power and torque are not fundamental stand-alone entities. Power vs RPM is all that matters.
Stand alone entities? What? One is a function of the other...
So here the question that keeps me awake at night...Building one of those c4 kart things for autox, running 315 to 345 18" Hoosier A7, estimating at around 1900-2000lbs. Question is do I build the sbc for lower tq or higher end power can make up 500 crank hp/tq? Given as you know autox is usually run in the majority of one gear wih lots of low mph digs ranging from 15-75mph. With low end tq I'm wanting to start and stay in 1 gear with top mph being 68 mph @6500rpm , high end power reving to 7600-8000rpm, I'm thinking 1st should rev out very quickly and grab second...final drives can be changed to fit a certain mph. Stock stuff is good to the 68mph@6500rpm and it always sweater to win with less. Great videos
give more detail no f...g idea what the h.ll you are wiriting about anyway put both setup powergraph on each other related to velocity this one which is higher at specified velocity be accelerate harder at this velocity
.
@@mociczyczki good lord I wrote that over a year ago, and I don't even know what the fuck I was getting at.
@@Roller_ae86 :D
Good Evening Kyle. Can you explain me why turbo engines have the maximum torque in lower rpm (like diesel ones) when compared with the same power non turbo engines?
Because turbo can suck in so much air into the cylinder, more air, more fuel, means a bigger combustion, which means more torque.
because road cars have little turbo's
Modern turbo engines serve as what I would call Displacement Lite. No replacement for displacement, expect maybe forced induction. Turbos are basically able to shove more shit into a smaller cylinder and force it to act like a bigger cylinder.
If you have a 2.0 liter naturally aspirated engine and a 2.0 liter turbo, the turbo engine is going to act like a much bigger engine than it is. So it's going to put out much more torque than the same displacement engine. Because it's essentially a shortcut for displacement.
How about diesel engine vs longer crankthrow of harley davidson engine? Which is more TURKEY?
It depend on setup but disel with turbo at the same displCement will have more torque at crank 👍🏻
*should you shift when the power is at peak or when torque is at peak??*
ACreativeName Neither. You should shift when you have more power available at the next gear than at the current gear or you hit redline.
Has a cyclist more torque in low RPM? As much RPM can you move the legs, do you have more power?
Thanks :)
Yes, because you won't loose torque on moving legs themselves so much, fighting inertia.
Obviously, you're gonna have the more power the faster you move the legs though.
That is until the point when all your power is lost on moving the legs and nothing is pressing on the pedals.
rate of work done by torque is power. in it right?
+Levi Ackerman yes, rate of work done by anything.
I get it, but…
(engineering/practicality question)
A 2008 Diesel Ford 6.4Lengine makes 350 hp. A Ferrari 458 Italia 4.5L makes 562 hp. With a different finale drive ratio (or a CVT for both) the Ferrari engine would be better at towing.
It would be odd if a Bus was revving to 10,000 RPM but in all likelihood it would be more effective… right? Are diesels popular because they’re easier to build/build around?
I assume that Ferrari or Ferrari like engines are also more expensive to build than diesels. Lower RPMs mean less strain/wear on clutches, torque converters, fuel economy, and gears.
low rpm high displacement high torque low bhp engineare use for towing because: less sclutch damage ., les fuel cosnumption , biger milleage thats 3 probably determing reason also noise is less painfoul for ear :x and with gear you also right however noit necessery with enough wide peak you can hold similar gear cuantity like in typical disel engine just with diffrent starting ratio = much more rpm vs wheel rpm .
How come the engine curves you drew and graphed didnt intersect at 5252 rpms?
He's not using American units (HP and lbf·ft)
How did you do the overlapping graph? What is it based on?
For Imperial /Standard HP and Ft-lbs the equation is...
rpm x Ft-lbs/ 5252 = HP.
That is why ALL dyno curves at are real will have the HP/TQ cross at 5,252 rpms.
Metric guys it's...
rpm x NM / 9549 = Kw
JerseyMikeP Thank you, but I meant the optimal-shifting-point, and torque-in-different-gears- graph
Ok, Now I know what you are looking for.
That really depends on the powerband, Transmission gear spacing and rev limiter. If you have a Dyno printout and know the gear ratios you can determine the Rpm drop between gears. Easier yet is have a Torque @ the wheel chart like Kyle has in this video.
Everyone "Thinks" shifting at the redline is quickest but that isn't always the case. You can see this by Kyle's Wheel torque graph @ 8m and 8:10.
Where the Torque @ the wheels drop below the next gears line in this video is when the shift should happen to be most efficient/quickest.
With only a Dyno graph, You have to calculate when the rpm before the shift matches the power level after the shift and how many rpms it drops. You just need to calculate the engine and wheel RPM before the shift and knowing the transmission gearing find calculate what the engine rpms drop to after the shift for the same wheel rpm. With that on a dyno graph you can find the points on the curve that the before and after power levels are equal.
For example if you make 240hp @ 6,000rpms and are in 3rd gear and shifting to 4th drops you to 4,500rpms where you are also making 240hp, that is the Ideal shift point.
JerseyMikeP Thank you, i figured it had something to do with gear ratios, is there an app or website that does the calculation for you, or one that makes this graph? I'm too stupid to calculate it myself, (and It isn't really important, I'm only 16yo, cars are kind of a hobby to me)
You still need to find a engine dyno graph for the car.
I found this site that calculates it for you....I never used it (and it only has a few rpm inputs (10) so it would only get you close) glennmessersmith.com/shiftpt.html
I would put in the (5) HP and RPms in 250rpms before and (5) hp/rpm increments above peak power. Most people would have trouble hitting an RPM shift in a smaller increment.
Cool thing about the site is that it gives the MPH to shift at...which most people on the street are looking at anyway.
Great video! Thank you so much for creating. One request: Please speak a little slowly.
Power Vs Torque: What Delivers Maximum Acceleration?
th-cam.com/video/fLuxGJk0kb8/w-d-xo.html
Peak torque is where the single combustion "works at its best" and puts the greatest force onto the crankshaft.
While highly unscientific it should be true, is it?
But peak tq or peak hp says nothing about fuel useage.
well it is just part of what determines fuel consuption.
if you drive around at 4000rpm -at (assumed) peak torque- you won't get great fuel mileage.
however peak efficiency and "fuel usage" are two different things.
yet it should be true that an engine at peak torque puts the greatest force (->torque) onto the crankshaft with the air and fuel that it is given.
Higher rpm and more air and/or fuel is unused but still power increases (to a certain point).
So exaust scavenging (due to valve overlap, exhaust system properties, etc), intake, fuel vaporisation, fuel ignition, burn, etc
they all work at its best to transfer force into the piston at peak torque.
Any more rpm and you start to waste fuel for the sake of more power.
At higher revs, you can use a shorter gear for any given road speed, therefore torque is multiplied by a greater factor at the driven wheels. Whilst torque is measured, power is really a calculation of how useful the torque being produced is due to the ability to use gearing to multiply it.
+Kalimerakis and +fierydawn and +Chad W , I may be able to help. +Damon Ethakada is right. I think we're dealing with two interdependent misconceptions. To briefly state the answer:
1) it would actually give best efficiency at peak power (I know this can be a frustrating mind-bender... just read on:)
2) it would only give best efficiency at full throttle
Now in more detail:
1) If an engine is running at the rpm for it's peak *torque*, then assuming the stoichiometric (fuel / air) ratio is still ideal *and it's still at full throttle*, then this is the rpm at which the engine is twisting the hardest for amount of fuel going in. But we don't just care about there being a twisting force, we also want to move... the faster the better. Best efficiency would be where we are moving as fast as possible, accelerating the fastest, or gaining altitude the quickest for the fuel going in. How do we move faster? From more torque at the wheels. Okay, so then we want the most torque from the engine, right? *Nope!* Not if the engine could be turning 10% faster and producing only 3% less torque. Why? Because gear ratios are in our control. We can adjust the gear ratio a little to turn that 10% extra rpm into 10% extra torque at the wheels. Torque form the engine reduced by 3%, so were still seeing around 7% more torque at the wheels... so we go faster, accelerate faster, climb faster!
I know it's really tempting for people to see torque as the most important thing, but because gearing is in our control, we actually want as much torque as we can get at as high an rpm as we can get (torque x rpm = power) so that we can adjust gearing to get the most torque at the wheels. This is where you can start to see the elegance and usefulness of power as a metric... Enter +Damon Ethakada's comment.
2) Obviously, +Kalimerakis is right, you would never expect to get good mpg screaming around at 4000 rpm (or given what we've just learned, maybe 4400 rpm:). That's because you wouldn't be anywhere near full throttle just cruising around at that rpm. Those curves would be totally invalid.
If you took a an average car that required say 15 hp to cruise at 60 mph, and you replaced it's engine with a little tiny one that just made 15 peak HP, then yes, It would get the best mpg (extremely good actually) screaming along at 60 mph with the pedal to the floor.
Side note: This is actually the only thing that makes a (non-plug-in) hybrid more efficient than a standard car. All the energy still comes from fuel, but by adding in the whole electric side of things, they are able to *work a smaller engine harder and thus, more efficiently*. That energy is stored in batteries and released by the motor when the car needs more than the maximum power of it's puny engine.
Another fun fact: Though nobody bothers doing it, you could actually test a normal engine *at low throttle* and plot torque and power curves. If the throttle setting you picked happened to be exactly the throttle required for cruising on the highway, then you could select a best rpm by just taking that for peak power... but then to adjust to that rpm you will probably have to adjust throttle which invalidates the curves... so then you have to pick again and test again... what a mess. This is where engineers take over;)
Also, about the stoichiometric (fuel / air) ratio, most engines are set up to provide a richer mixture at high engine rpm and load. This is the other reason why your peak HP rpm is not an efficient place to drive.
Hope this helps.
For the engine's thermodynamic efficiency, yes. For mileage, that is = engine fuel consumption rate x vehicle speed. So for max mileage, you need lower revs, but higher speed. Hence overdrive gears.
but bro how a naturally aspirated engine torque curve differs from a turbo torque curve?
When you say faster you mean acceleration, I assume. So you said "power is faster" so with that in mind, have you seen a tesla dyno graph?
Do you know that tesla have tires which looose grip when you exceed 1,1-1,2G in good condition ? thats why it cant use efectivelly more power from stand still if tesla plaid let say is capable of pump out 1 G at 100 km/h than quees how much G theoreticaly it could hit at 10 km/h assuming we change gear ratio in such way that tesla will produce max power at 10 km/h assuming drive train stand this without ripp off apart on 100 pieces and assuming we have enough gripp offcorse ? =10G driver will be push into seat with 10 times biger force than now and 99% people include top fuel driver will be shocked how strong it accelerate at those veloicity with our new gearr ratio which use engine peak power rpm offcorse normal road tire which tesla have loose grip almost 10 times earlier and probably its stock drive train will break if we do such thing ....
Tq = $/hr
Rpm= hours worked
Hp= Salary
If you want to buy stuff, you need to know how much you make.
Person 1: "Average car"
20$/hr wage, 40 hours a week = say 2,400$ a month tq x rpm = 1,600 units of energy to use to move the car
Person 2: "used piece of crap car"
Minimum wage, 25 hours a week = 1,000$ a month 1,000 units of energy to use
person 3. Sports car
40$/hr, 40hours a week = 6,400$/month 6,400 units of "spending cash"
person 4. Formula Car
50$ an hour, 100 hours a week = 20,000$ a month
As you can see, you can't buy something when all you have is a job pay rate(tq) with no hours worked(rpm). This is like saying how fast a car will be knowing its tq output. It needs more information.
That is also no different than saying, I can afford that when all you know is hours you can work but dont know how much you make per hour.
Hp is how much energy or money you have to work with, when dealing with spending it or buying things. This is just the same as Hp in a car.
TQ(hrly rate) is the effective rate of pay per unit of time worked. This is just like tq. How much can you get out of each piston explosion.
hours worked or RPM is how many of these explosive units are being used.
Now what is actually at the wheel as far as hp and tq. Just think of it as tax on money. What is taken to get the money in your pocket. Sure you motor made 200hp before taxes. but after its 176whp after taxes.
This analogy works perfectly. Its what everyone should think of. cause words like horsepower are not needed. tq x rpm = ______ is all you need
another way to think of it is this.
Tq is 2 units. force at distance. That makes a 2 dimentional plane. Where one side of length (tq number) and the other side of the rectangle is length (distance of force applied to make said tq)
Rpm is making the 2d plane a 3d one. so....... Force (side 1) X TQ (side 2) X Rpm (side 3 = a 3 dimentional square or box. the Volume of this box is called POWER..... the bigger the box, the more powerful. Its in this BOX that you can manipulate it with gearing to change the shape of the box to fit your needs. But 300hp is always 300hp and cant be changed in volume regardless of gearing. And 300hp box will always have more volume than a 250hp box. Tq can not make up for more hp cause hp already incorporates this into the size dimensions of the box created.
so 300tq making 300hp is not more powerful than 100tq making 310hp. Hp wins PERIOD
If Power is dependent on Torque. As we know Torque x RPM = Rotational Power, How come, Power is still constant while Torque is decreasing?
because rpm increase .
And what about electrical cars ? With no gearbox or 2 gears ?
electric engien have constant peak torque from 0 rpm in 95% egzample now than do final ratio gearing that in 1 egzample from 20 to 40 km/h you be have from 2000 to 4000 rpm and in second from 4000 rpm to 8000 rpm and let assume that cinstant peka torque at engine crank is fromm 0 to 10000 rpm which setup achieve 20-40 km/h faster? correct answer is 4000-8000 rpm 2 times faster beacuse it will use average 2 times biger power and in the same time 2 times biger wheel axis torque = for electric engien aply the same pricnicple and physique dependdencys as for combustion engine they are just lil diffrent build etc :x .
Hi
I have a question about power and torque
I understand 90% of it but one thing i dont understand.
If for better acceleration we need power not torque, so why in my car 1.8t chipped i feel better acceleration for example on 3rd gear betwen 2,5k-4k rpm (where average power and torque is 135hp & 290Nm) than between 4,5k-6k rpm (where average power and torque is 180hp & 240Nm) ??
I know there is a air resistance but i dont belive that is so big. Same feeling on 2nd gear.
Same example is in diesel 1.9tdi 130hp.
On 3rd gear at 4k rpm (max power) accelerate slower than at 2.5k rpm
All I want to know why I fell more counter force on my seat when I 'am betwen 2.5k-4k RPM than between 4,5k-6k RPM although power of engine is bigger there
Why is that?
I think, by the time you get to 6K RPM, you are going a higher speed at 3rd gear, fighting more resistant forces (included but not limited to drag). If at same very speed you switch to 4th gear, dropping RPM below 4.5K, your acceleration will decrease.
If you dynamically switch gears to stay as much as possible between 4.5 and 6K RPM, you'll get the best acceleration.
because you do test at the same gear this is often misteake people who try find answer and test this in theyr car ., what must be conssidered is you must compare acceleration at egzacly the same velocity let say 80-120 km/h if you ddont do this its pointless ., if you do test beewten the same velocity you will seee that 180 bhp /240 nm push you around 30% stronger than 135bhp/290Nm .., go compare let say new 650 bhp porshe 911 turbo s 100-200 km/h in 6,0 sec vs subaru impreza 300 bhp do 0-100 in 4,5 sec do you reaaly want comapre 1000-200 time with 0-100 time ? ITS POINTLESS so wwhat subaru can do 0-100km/h faster than 911 100-200 km/h put both on drag race let say 1/4 mille and 911 crush subaru and when you comapre both at the same velocity no matter which except maybe couple first metres where diffrenc cant be shown because both car limits theyr limited grip but at each other velocity porshe be faster 50-100 km/h 911 in 1,3 sec vs subaru in 3 sec 100-200 km/h porshe in 6sec vs subaru in 13-14 sec and so one this egzample show what is your misteake you comapre acceleration at compeltely diffrent velocity because you use the same gear ! egzacle like with 911 turbos 100-200 vs subaru 0-100 stats thats comepetely diffrenc velocity ! how you want comapre it ? velocity must be the same than180 bhp /240 Nm easy beat 135bhp/290Nm i do similar test with some 1,7 cdti car more power less torq when im use biger rpm give 0 chance more torque less power at lower rpm from 20 to 100 km/h watch this and this happen in each car and motorcycle th-cam.com/video/fKXc5eGUokI/w-d-xo.html i also comapree for egzample 160nm 60 bhp car vs 125 nm 100 bhp car both the same weight ata the same road and 100 bhp 125 nm car beat 160or 175 nm 60 bhp car all the way from 0-100 km/h let say 10,5 vs 17 sec..so what you have higher torque at crank when engine spin much less rpm 100 nm at 5000 rpm beat 200 nm at 2000rpm at egzacly the same velocity 10 nm at 10000rpm beat 1000nm at 1 rpm at the same velocity so such you will get the best torque at the wheels by shifting to whichever gear gets you the most power= more engine power at a lower gear pushes harder than more engine torque at a higher gear at the same vvelocity thats fact= suppose max torque occurs at 2400 rpm and it dont give max power and max power occurs at 4000 rpm, first gear is 4000 rpm at 50 km/h and second gear is 2400 rpm at 50 km/h. Then if you are going at 50 km/h, first gear will get you better torque at the wheels....
civic type r 200 bhp 200 nm 1300 kg vs seat tdi 160bhp 330 nm 1300 kg like you see civic push driver harder into seat th-cam.com/video/kalq2iN9Yns/w-d-xo.html .,
cbr 400 rr nc 23 59bhp/39Nm 180 kg weight 0-100 under 5 sec th-cam.com/video/Vh7esjikjz4/w-d-xo.html vs suzuki s40 650cc 31 bhp/50 Nm 180 kg 0-100 in around 8 sec th-cam.com/video/Vwj9uy5ELMA/w-d-xo.html holly sh.t dude i quees its oposit to yor claim ;)so instead of using diffrenc velocity try accelerate as fast at at max power 184bhp/240 nm but at the same velocity be using 135bhp /290 nm so you must put in higher gear to accelerate at more torque less power at the same velocity level than you seee idi.t how much weaker is in fact 135 bhp/290 nm comapre to 184 bhp /240 nm heheheheh .... physique math perfect expalin this and proper executed test .
or how do you think why each automatci gearbox is setuo in manufactory for use peak power rpm and not peak torque rpm when driver want to accelerate as fast as posiible ? yea beacuse like im write earlier max acceleration at specified velocity can give only max power ., go watch some vide witrh acceleration 2021 car with 7-10 dsg gearbox automatic each be use peak power rpm not peak torque ..
Can we not say that all other things being equal, the acceleration of a vehicle at any given speed, is determined by the torque produced at the driving wheels. So in that sense, "torque is king". The magnitude of the reduction in peak diving wheel torque between gears is most surprising, especially between first and second. I would have expected such a reduction to be far more obvious than appears to be the case.
I try to get your point...
The torque curve shows the relative power.
At acceleration through the rpm range on the same gear, you will get best acceleration at the rpm where the torque is highest.
At a given speed you will get best acceleration if the engine runs at the rpm where the power is highest(which is not always achieveable).
In both examples it's actually about power: relative vs maximum power.
Actually we don't need to talk about torque at the driving wheels, but instead force. And force = power/speed.
@@patricj951 I'm not sure that I understand. If we look at the chart at 7:00 for example, we see that to maximise acceleration at any road speed, we must maximise the torque at the axle. As simple as that. It doesn't matter how powerful or torquey the engine is, if you cannot deliver that power to the axle, in the form of a higher torque at the given road speed. So that's where driver skill, gear box ratios, and power curve profiles come into play. If we look at the linear equivalent formula, F=Ma, for any given mass M, its acceleration will simply depend upon the net force acting upon it. Similarly neglecting frictional forces, the acceleration of a vehicle will simply depend upon the force (axle torque) driving it forward at the given road speed.
@@60sfanatic Does he not say in the video, that higher torque is related to higher power? What I mean is that higher torque is good because it results in higher power. So there is no battle between torque and power.
Force = power / speed. And acceleration = Force / mass.
Well, this may be a bit complicated so I may misunderstand you...
@@patricj951 Well a tractor has extremely high torque but its not going to win any races. Because the torque can only be produced at very low speed. So a high performance (high power) engine needs both torque and speed. (RPM) (Power = constant x torque x rpm) And one can in effect, be traded for the other, through gearing. Right?
@@60sfanatic
Right! The mistake in this topic is often that when people use the term torque they mean at low rpm and when they use the term power they mean at high rpm. But these things are not separated by the rpm.
While high torque at low rpm results in high relative power at low rpm, torque is not strength at low rpm. And power is not strength at high rpm.
And in many cases the maximum torque value is used as a sign for strength at low rpm, which can be very wrong if the high torque is not available at low rpm.
It's very common that people when they talk about power mean the maximum value which is at high rpm while they talk about torque mean the torque at low rpm.
What I mean is that this debate can be very wrong if you only talk about numbers while
not take in consider the rpm or curves.
Sorry if I make this complicated...
I want to pull caravan.
Someone told me that we need car with a lot of torque.
I think he's wrong, couse we need power to pull this caravan couse Power makes acceleration.
Which vehicle pulls stronger?
vehicle A with constant 2000 rpm with 500Nm
or vehicle B with constant 13000 rpm with 100Nm?
In my opinion Vehicle B couse it has more power
(185hp) than vehicle A (142hp)
I know 13000rpm is irrational and better is to have car with a lot of low rpm power. But in this example vehicle B pulls stronger
Am I right?
wyskun You need to have good power throughout the usable rpm range. It gets old really fast if you constantly have to shift to keep the engine howling around its peak power rpm.
More low-end torque means more low-end power, causing you to be able to drive at lower rpms more often.
You basically need both to have a pleasant to drive caravan puller: good torque at low rpm which doesn't drop off too drastically higher up so you also get good power at higher rpm.
Gear ratios are important too, a car with 30% more low-end torque than an other one (same weight) will still be slower to launch if it has a 50% taller 1st gear total gear ratio.
yea your right 👍🏻 except launch where you must also including clutch friction losesss etc + thers go into play gearing so for 13 k rpm setup you can use much shorter gearing and decrease diffrenc in clutch sliding at launch itself also play role weight of rotational onertia in engine flywhell and so fprth but once clutch is fullly closed and both setup be like you write from let say 5 to 150 km/h in did 13 k rpm with 100 nm will pull stronger load with better acceleration to biger topspeed uphill down hill or on level road dosent matter cos it generate more power than 500 nm at 2000 rpm 👌🏻 and offcorse nobody make truck with 1 litres n/a sports bike engine from multiple reason but yea it will pull harder than 142 hp V8 10 litres engine with proper gearing 👌🏻
@@Candisa yea 1000 nm at 1000 rpm 200 hp at 2000 rpm is better for towing stuff but 500 nm at 5000 rpm 400 hp at 8000 rpm with proper gearing still be pull harder 👌🏻 so hees right except launch where come into play such factor like rotational inertia clutch friction gearing but once clutch be fullly closed assuming the same roatational inertia asf hees right 13 k rpm 100 nm beat 500 nm at 2000 rpm cos 13 k rpm at 100 nm is more power so only for such test hees right 13 k rpm at 100 nm win this that it be worse setup for most driver especially with manual gearbox thats doffrent story ,also diffrent story be with automatic or cvt where driver do nothing stilll very big rpm would iritate him so he still would choice 500 nma t 2000 rpm version or setup cvt 😉 + wear and engine longevity and fuel consumption be worse on 13 k 100 nm setup so naturally nobody buy it 👌🏻 hees egzample just prove simple issue that 13 k rpm at 100 nm in did will pull stepnger heavy load than 500 nm at 2000 rpm cos it generate more power period .
Since F = m *a , does that mean that highest possible acceleration is available at peak torque?
Only in THAT particular gear, it doesn't apply when you have to shift through gears.
Actually Power = Force x velocity. So at any given speed, maximum acceleration is available where power is maximum, as gearing can adjust the torque at the wheels.
so 130 i accelerate better /push stronger ddirver into seat .,th-cam.com/video/H3PV3Sj1nkA/w-d-xo.html notice driver in 130 i start when 120d have like 15 km/h and he start from to low rpm still reach 100 km/h first .
I just dont understand why the power is going down after the peak, explain please.
As far as I know, usually friction gets more prominent, at high engine speeds. Also, it wouldn’t be a peak if the power kept going up ;)
The intake and exhaust of an engine are designed to flow the most air within a certain RPM range of the engine. above and below that range, the engine isn't flowing its optimum amount of air and you get less than peak performance.
in a purely mathematical exercise, the power doesnt go down. it would continue going up, multiplying tq and RPM continuously. real engines cant run like this
the power going down is a result of the physical limitations of the engine. the engine cannot flow enough air to increase power or the RPM gets too high and the engine falls apart. this is why engines have a "redline." above a certain RPM, you wont make more power, you just risk damaging the engine.
If you want more accelleration you need more power
if you want to pull something heavy you need power
if you want to go uphill faster you still need power
and if you want to increase your maximum speed you need tor... no you still need power
engine torque is just not into the equation
Fede Devi torque is what helps you get off the line
@@jaarryifleshblood315 Nah you need a force pushing the car. If anything you need a bigger flywheel.
so true .
Powahhh
While I do like manual transmissions and revvy engines, of course there's a factor that can actually make torquey cars faster than higher power/low torque cars: the time you spend shifting (especially manually) in a lower torque car and thus have no power applied to your output shaft, while the guy in the high torque car can just skip gears and keep going.
I love to shift and to rev out my engine tho, even though sometimes I'd also like to have a liiittle more torque down low (2l NC MX-5).
oł je so comapre honda nsx 275 bhp 280 nm 1350 kg to let say bmw 120 d 163bhp 340 nm ., however this wwhat you write is true if more peak engine is very narrow and have big diffrenc in gear lenght beside this so what let say you msut change gear 20 times assuming acceleration f0rm 0 to 200 km/h vs in some more torque at crank engine only 3 change when you use average power level of let say 300 bhp and him 200 bhp you still be pull away form more torque engine such situation like yoiu write can be achieve only when diffrenc in average power use be engine is enough small comapre to shifting time and shifting cuantity than you can be setup corret proprotion achieve egzacly the same acceleration in terms times distance final velocity or worse or better depend on rpoprtion yea it is achievable what you write but like im wirte you need enough small diffrenc in power otherwise more power les torq engine win .
@5:53, And that's why electric vehicles like a Tesla don't need a gearbox (some other vehicles use 2 or 3 speeds at the most). The torque curve of an electric motor is flat peak torque till max power is reached at some rpm, and then the torque is inversely proportional to rpm thereafter. This is also the curve that gives max acceleration as you have maximum power available at any given speed. As F = P/v, the more the power at a given speed, the harder the car will accelerate at that speed. At very low speeds, this gives the impression of a "torquey" engine, which is true, but this is actually what it means. Axle speed is a proxy for linear speed (the one your speedometer shows) and simply put, if at 60 mph in the same gear, one engine is making more power, all other things equal, then that engine is also producing more torque at 60 mph and that car will accelerate faster.
only trouble is that you dont have max power at any given speed when you haeflat torque and power still grow :x flat torque isint best characteristic flat power is .in fact best characteristic is to have as much power in each time to get on border of tire grip at least for racing or towing ....
this is one of the better expiation but you do make a big mistake.. when you give a torque number with a rpm.. you are specifying power.. i prefer to explain it torque@rpm and hp@rpm are the same thing.. like feet and meters.. even explain that you can give power as hp@torque..
When you accelerate quickly at low speed the torque to do so requires a certain fuel input to the engine. Now at a higher speed if you want the same acceleration you want the same torque but the engine is spinning faster at the higher speed, so the fuel input is higher even though the torque is the same. The engine is making the same torque but doing it much more quickly so it needs more fuel to make the same torque at the higher speed.