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I posted this on one of the Facebook Olds pages after seeing some comments on another post that made it obvious that some don't understand the difference or the relationship between the two.
Torque is simply a measurement of force while horsepower is a calculation of potential work output. Horsepower = total force (torque) applied over time.
I will try to explain with an analogy. Think of it like two guys racing on ten speed bicycles. One is a powerlifter (the "torque" engine). The other is a sprint cyclist (the "horsepower" engine). The power lifter's legs can generate much more force but at a much slower rate. He can only pedal so quickly. The sprint cyclist's legs can't generate nearly as much force (torque) per pedal stroke, but he can pedal at a much faster rate than the powerlifter. He can apply his lesser force much more frequently than the powerlifter, applying more total force over a given amount of time (horsepower).
Now think of these two racing their ten-speed bicycles and which would be quicker. If both were forced to race only in 10th gear the power lifter would have an advantage, especially at the start because he can generate more force per revolution, more easily overcoming the resistance. The problem he will run into is once he is up to his maximum pedaling speed, he is now limited to how much work he can do by the rate at which he can pedal. He can only apply his great amount of force so rapidly limiting his work potential (horsepower).
Now let's change the rules and allow both to choose which gear they want to start in as well as shifting gears as they please throughout the race. The sprint cyclist now has the advantage. He can start in a lower gear which multiplies his force input. He can then take advantage of his much more rapid pedaling rate. By applying his lesser pedaling force much more frequently, he is able to apply more total force over a given amount of time (horsepower). He can now shift gears to continue to accelerate while maintaining his much higher pedaling rate (rpm) to do more total work over a given time frame. He will now easily win the race.
Great explanation, right up to the point where you allowed both riders to use all their gears.
I probably would have stopped there because it puts us down the rabbit hole of variable torque multiplication: either rider could regain the advantage by using different ratios and shifting at different leg speeds, much like we would with our cars, by choosing different axle ratios in conjunction with different transmission gears and experimenting to determine the best shift points for a particular combination.
Kind of morphs into a whole other subject, perhaps best saved for Chapter 2.
Great explanation, right up to the point where you allowed both riders to use all their gears.
I probably would have stopped there because it puts us down the rabbit hole of variable torque multiplication: either rider could regain the advantage by using different ratios and shifting at different leg speeds, much like we would with our cars, by choosing different axle ratios in conjunction with different transmission gears and experimenting to determine the best shift points for a particular combination.
Kind of morphs into a whole other subject, perhaps best saved for Chapter 2.
Yes, in the above analogy shifting gears is beneficial to both cyclists. If it wasn't, diesel pickups would have only one forward gear. It is much more beneficial to the cyclist with less torque and the much faster pedaling rate. Remember, horsepower is total torque applied over time. Ask yourself this. When was the last time you have seen a 1/4 mile performance calculator that asked for a torque input? You won't because they are all based on torque over time, otherwise known as horsepower.
Ask yourself this. When was the last time you have seen a 1/4 mile performance calculator that asked for a torque input? You won't because they are all based on torque over time, otherwise known as horsepower.
I imagine to be of any actual use, a 1/4 mile calculator would need to include complete curves for both horsepower and torque from off-idle to maximum anticipated RPM. Otherwise it's just a fun video game.
I imagine to be actually useful a 1/4 mile calculator would need to include complete horsepower and torque curves from off-idle to maximum anticipated RPM, along with all relevant gearing, traction and weight information. Otherwise they're just fun video games.
They can actually be fairly accurate as an estimate for 1/4 mile potential. Torque applied over time is horsepower. Horsepower is the potential to do work. In this case, a drag race is the work.
Read my first post again until you fully understand this concept.
I will use my own car as an example. Plug 931hp (what's on my dyno sheet) and 3215lbs (what my car weighs) into the calculator linked below and see what you get. Then look at my E.T. listed below my sig pic. Pretty damn close.
I imagine to be of any actual use, a 1/4 mile calculator would need to include complete curves for both horsepower and torque from off-idle to maximum anticipated RPM. Otherwise it's just a fun video game.
from the MPH and the RPM you cross the line at, you can calculate the TQ
A dyno only measures the TQ an engine makes..it’s measuring a twisting force. The dyno has a strain gauge or transducer to measure how much it is pulled or pushed out of shape
it doesn’t matter at what RPM the TQ is calculated at, if you can make more TQ over a previous pull, at the same RPM, it means you made more HP. So you always want to make more TQ (not where peak TQ is, but more TQ at the same RPM than before) you want the peak HP RPM in a drag application to happen at or just before the stripe in high gear.
towing and other apps are completely different
I don’t know why the video I posted earlier won’t work? It’s excellent because it’s gets into gear ratios
A dyno only measures the TQ an engine makes..it’s measuring a twisting force. The dyno has a strain gauge or transducer to measure how much it is pulled or pushed out of shape
it doesn’t matter at what RPM the TQ is calculated at, if you can make more TQ over a previous pull, at the same RPM, it means you made more HP. So you always want to make more TQ (not where peak TQ is, but more TQ at the same RPM than before) you want the peak HP RPM in a drag application to happen at or just before the stripe in high gear.
towing and other apps are completely different
I don’t know why the video I posted earlier won’t work? It’s excellent because it’s gets into gear ratios
I'll add to this that making the same torque but at a higher rpm also equates to more hp.
I'll add to this that making the same torque but at a higher rpm also equates to more hp.
yes..and you’ll ET better and go faster in a drag app by taking advantage of having more RPM by using more rear gear and being able to RPM higher in each gear before shifting .
a perfect example of that taken to the extreme is an F1 engine. Say it makes 1,000 HP at 15,000 RPM..that’s 350 ft/lbs at that RPM. Those engines operate in a very narrow RPM range. An engine like that would need many many gears to pull from a dead stop
Last edited by CANADIANOLDS; Mar 20, 2024 at 05:46 AM.
Read my first post again until you fully understand this concept.
I have, several times now, and it still seems to me that you're conflating engine output with transmission characteristics. I think the discussion of gearing just muddies the water of the original horsepower vs. torque analogy, which was quite aptly presented.
Torque is rotational force. Force, in itself, is linear. The pressure of the flame front times the area of the piston yields a linear force. That, times the lever arm of the con rod and crank, times number of cylinders, gives you the torque of the engine. Similar to the amount of linear force you put on a lug wrench to turn into rotational force.
The word is integral. Power is force integrated over time, and you can do neat calculus to show this. Just like distance is velocity integrated over time. Incidentally, energy is power integrated over time, for one step further.
The initial analogy is flawed because it assumes gearing advantageous to the high speed engine. One of the problems amateurs have with engineering is they assume something is BETTER all the time, when, chances are, if something exists, it is the best at one thing and worse at others. Engineering is a compromise and choices are made for needs. The reason high horsepower / low torque engines are chosen for formula one is not because of gearing, but because of weight savings. On the other hand, drag engines are chose for torque.
As for the stupid meme, that's dumb car guys trying to use engineering and physics terms without any education. If we must use the meme, kinetic energy is how hard you hit the wall, and momentum is how far you take it with you. Incidentally, momentum and kinetic energy are related the same way force and power are; integrals again.
Torque is rotational force. Force, in itself, is linear. The pressure of the flame front times the area of the piston yields a linear force. That, times the lever arm of the con rod and crank, times number of cylinders, gives you the torque of the engine. Similar to the amount of linear force you put on a lug wrench to turn into rotational force.
The word is integral. Power is force integrated over time, and you can do neat calculus to show this. Just like distance is velocity integrated over time. Incidentally, energy is power integrated over time, for one step further.
The initial analogy is flawed because it assumes gearing advantageous to the high speed engine. One of the problems amateurs have with engineering is they assume something is BETTER all the time, when, chances are, if something exists, it is the best at one thing and worse at others. Engineering is a compromise and choices are made for needs. The reason high horsepower / low torque engines are chosen for formula one is not because of gearing, but because of weight savings. On the other hand, drag engines are chose for torque.
As for the stupid meme, that's dumb car guys trying to use engineering and physics terms without any education. If we must use the meme, kinetic energy is how hard you hit the wall, and momentum is how far you take it with you. Incidentally, momentum and kinetic energy are related the same way force and power are; integrals again.
F1 cars have a minimum weight they have to be..so the weight savings thing is bs. They limit the RPM to slow the cars down, just like they do in NHRA pro stock. Because the fact is, the more RPM you can turn, the faster the car will be because you can gear it to take advantage of the higher RPM.
most forms of high end racing now limit max RPM as a way to slow cars down and make racing more competitive..which is debatable. NASCAR does it through gearing and high drag downforce.
look at NHRA stockers..where there is no RPM or gearing rule. It’s incredible how quick some of the low HP and low TQ engines are..all because they have increased their RPM’s. If you can figure a way to up your RPM and still make the power, you will be a step ahead of the other guy
back in the 80’s FJ Smith was turning his small block Olds 10,500+ RPM’s. Which was insane…and way more than his competitors.
Last edited by CANADIANOLDS; Mar 20, 2024 at 12:07 PM.
Dale wrote: look at NHRA stockers..where there is no RPM or gearing rule. It’s incredible how quick some of the low HP and low TQ engines are..all because they have increased their RPM’s. If you can figure a way to up your RPM and still make the power, you will be a step ahead of the other guy
Bernhard wrote:
I agree it is impressive the rpm and ET's that the stock class racers are achieving. What I find interesting is that there are a few high tq big block cars that are one under running lower rpm and less gear. This is not the norm, I have never heard of a small block car being able archive this kind of performance with out tall gearing and rpm. Cars I'm referring to are 3550 LB's and run in the 10's.
I posted this on one of the Facebook Olds pages after seeing some comments on another post that made it obvious that some don't understand the difference or the relationship between the two.
Torque is simply a measurement of force while horsepower is a calculation of potential work output. Horsepower = total force (torque) applied over time.
I will try to explain with an analogy. Think of it like two guys racing on ten speed bicycles. One is a powerlifter (the "torque" engine). The other is a sprint cyclist (the "horsepower" engine). The power lifter's legs can generate much more force but at a much slower rate. He can only pedal so quickly. The sprint cyclist's legs can't generate nearly as much force (torque) per pedal stroke, but he can pedal at a much faster rate than the powerlifter. He can apply his lesser force much more frequently than the powerlifter, applying more total force over a given amount of time (horsepower).
Now think of these two racing their ten-speed bicycles and which would be quicker. If both were forced to race only in 10th gear the power lifter would have an advantage, especially at the start because he can generate more force per revolution, more easily overcoming the resistance. The problem he will run into is once he is up to his maximum pedaling speed, he is now limited to how much work he can do by the rate at which he can pedal. He can only apply his great amount of force so rapidly limiting his work potential (horsepower).
Now let's change the rules and allow both to choose which gear they want to start in as well as shifting gears as they please throughout the race. The sprint cyclist now has the advantage. He can start in a lower gear which multiplies his force input. He can then take advantage of his much more rapid pedaling rate. By applying his lesser pedaling force much more frequently, he is able to apply more total force over a given amount of time (horsepower). He can now shift gears to continue to accelerate while maintaining his much higher pedaling rate (rpm) to do more total work over a given time frame. He will now easily win the race.
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Hopefully this helps explain things for some.
I'm a little late to this party, but I wanted to add a little real world data and humor. I once worked with a man that rode a bicycle in the Olympics for Grenada and told me lots of stories about the things they tried. They used the exact same comparison in the original example. They would have very powerful riders for sprints because their superior strength allowed them to reach max speed quicker and the race was not long enough for the higher speed riders to catch up. They had coaches brought in specifically to teach the cyclists how to increase their pedaling speed and produce power throughout the revolution of the pedal crank. One of the side affects of using such powerful cyclists sometimes resulted in simply pulling the spokes out of the rim, effectively ending the race. So once again, the comparison between torque and horsepower comes down to proper gearing.
