Is Torque King?

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273 said:
I agree with you I was making a quick point but if you took same weight cars that turn the same E.T.s if you Dyno and figured out there torque to the ground numbers I bet they would be similar through out the run.
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That's the thing - if you take the same weight, and accelerate it to the same mph over the same distance, you have effectively averaged everything into one number. ET is not the the number that really means much besides bragging rights. MPH is. That's because most savvy racers know ETs can be fiddled with easilly, and especially in class racing - they are. This is an observation and not meant as a cheap shot - I think you've generalized to the point that the numbers are the same because you want them to be.

Help me through this example - Let's assume two 3200lbs cars that run 125mph in the quarter mile:
Car #1 has a N/A 500" engine with a 3spd trans.
Car #2 has a midly stroked slant six with a big single turbo and a power glide.
They both cros the stripe at the 125mph mark. Which is faster? Which has more horsepower? Most importanly - how can you tell given the info supplied?

"Then they were wrong. And I'm not bein a smartass......it's got something to do with the physics of it. I cannot explain it all. I just KNOW torque and HP always cross at 5252 RPM......"

The numbers will only cross "every time" theoretically and on the dyno simulation programs. That's because the horsepower numbers are crunched. And the inputs for that crunching are data points based on human being created correction factors. Not all dyno operators think the same way and so correction factors can vary (or be skewed), plus not all dynos run the same software, and not all software uses the same number of data points per second for their calculations. That means there's a very real chance of error in the result when compared to a theoretical "always". So while theoretically using a mathematical constant they "will always cross" at 5252, the dyno sheets many believe as empirical truth may not show that torque and horsepower relationship
 
Hersbird said:
The torque of a torque wrench is not the same as the torque of a motor. Calling putting force on a wrench without turning it torque is somewhat incorrect. Without the movement the force applied to a wrench is called "bending moment" but is often wrongly just called torque. Torque is the force over a rotating axis, it has to be in motion to be torque. The general physics term "torque" could just be the pressure without movement, but in mechanical engineering, as in a car engine torque has to be in motion.

As I have said 3 times 100 ft-lbs accelerates the car equally at 3000 rpm as it does at 6000 rpmgeneral hough the HP is double. Doing more work, is not accelerating the car at a higher rate. Think of it as working smarter not harder.

The area under the torque curve (not HP) is the way to compare two motors. If the motor makes torque from 2000-6000 that is better then 2000-4000 but 4000-6000 is equal to 2000-4000 even though the 4000-6000 motor shows more horsepower. The 2000-6000 is better not because it will accelerate faster at any given point but that it stays in 1st gear longer multiply the torque longer, and then repeating that again in 2nd, 3rd, etc. But if the motor doesn't start making torque until 4000 rpm the time in each gear will be the same.
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You totally missed the point.... :banghead:
 
krazykuda said:
Horsepower is a measurement of work, meaning a force applied to an object and the displacement of that object in the direction of the applied force. What does this mean? One horsepower equals 33,000 pounds-feet per minute (4,562.41 kilogram-meters), or the energy it takes to move a 330-pound (149 kg) object 100 feet (30.5 m) in one minute.
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By your own definition HP is time-valued. Therefore HP is not work, it is work done over some time span. We see this in the calculation for HP; take the amount of work that can be done (torque) and multiply it by time (Revolutions Per Minute).

Torque is a twisting force that rotates or turns an object like a wheel. When you use a lug wrench on a bolt, you're applying torque to it. Unlike horsepower, even if the object doesn't move, torque can still be exerted on it. Torque is measured in pounds-feet, meaning a force in pounds acting on the end of a lever measured in feet. For example, if that lug wrench is 2 feet (0.6 m) long, and you put 100 pounds (45.4 kg) of force on it, you are putting 200 pounds-feet (27.65 kg/m) of torque onto the bolt. Read How Force, Power, Torque and Energy Work for more information on torque.

Once we're able to measure torque, we can then measure horsepower. The formula is simple: Multiply torque by the engine speed (measured in rpm), then divide that by 5,252 to get the horsepower at that rpm level. In other words, to get the horsepower of a vehicle generating 350 pounds-feet of torque at 4,000 rpm, you would calculate (350 X 4,000)/5252, which equals around 267 horsepower. It comes down to this: torque measures how much work is being done and horsepower measures how fast that work is being done
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HP is not measurable by an engine dynometer, it has to be calculated. It is a measurable entity, but I know of no such apparatus anywhere.

The reason that not all TQ and HP curves don't always cross at 5252 is because HP is a calculated value and in that calculation there are correction factors that are applied to make the results standardized to one common air temperature, barometric pressure, and humidity. Those correction factors can skew the crossing point, but that doesn't mean that you aren't also being lied to.

I won't claim to know everything about measuring torque and calculating HP, but I did spend from 2004 to 2011 working in a support Engineering role at an R&D engine dyno developing a diesel engine with some very unique features. http://propulsiontech.com/opocengine.html
 
moper said:
That's the thing - if you take the same weight, and accelerate it to the same mph over the same distance, you have effectively averaged everything into one number. ET is not the the number that really means much besides bragging rights. MPH is. That's because most savvy racers know ETs can be fiddled with easilly, and especially in class racing - they are. This is an observation and not meant as a cheap shot - I think you've generalized to the point that the numbers are the same because you want them to be.

Help me through this example - Let's assume two 3200lbs cars that run 125mph in the quarter mile:
Car #1 has a N/A 500" engine with a 3spd trans.
Car #2 has a midly stroked slant six with a big single turbo and a power glide.
They both cros the stripe at the 125mph mark. Which is faster? Which has more horsepower? Most importanly - how can you tell given the info supplied?
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Yes get what your saying there lots of variable when come to cars performance on the track.

But really that's not the conversation I'm trying to have
I'm trying to show Torque is no more of less important than RPM there yin and yang of an engines power just like amps and volts are for watts. Horsepower is the sum ability of Torque and RPM and through Gearing can be put to work for us. I'm not arguing the benefits of lower rpm Hp engine (torque engine) or high rpm HP engine (rev engine). A nascar engine can be gear to power a transport truck but I imagine it would last long.
 
It seem from most of the responses that people see that torque does the work from idle to 5252 rpm than horsepower takes it from there or torque launches your car and Horsepower takes it from there. Horsepower does all the work from idle until your engine can't spin any higher.

On a Dyno your engine is being measured for two things RPM and Torque and the horsepower line is calculated from the two it's the Sum of there combined abilities.

Visually torque curve works better for the way our brain perceives info, all the same info is there in the HP curve.
 
This statement:
"For the most part torque is a useless number once HP curve is found from it."
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is so ludicrous and wrong that I'm not even sure how to address it. Without torque you have no HP and nothing will get done. As I keep saying Torque is a measure of how much work can be done by the engine and HP is a measure of how fast the engine can do it. You need both, but how much of either depends on the use.

Gearing, tire size, and all of that has no bearing, that is Zero effect, on torque or HP produced. Mentioning that just confuses the issue and should be in a separate thread on how to apply what the engine produces.
 
273 said:
Yes get what your saying there lots of variable when come to cars performance on the track.

But really that's not the conversation I'm trying to have
I'm trying to show Torque is no more of less important than RPM there yin and yang of an engines power just like ohms and volts are for watts. Horsepower is the sum ability of Torque and RPM and through Gearing can be put to work for us. I'm not arguing the benefits of lower rpm Hp engine (torque engine) or high rpm HP engine (rev engine). A nascar engine can be gear to power a transport truck but I imagine it would last long.
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Ah. I understand what you were aiming for now. Tell me if we're in agreement:
Torque is the twisting force. A measured empirical value for a given moment in time. For purposes of this dicussion it represents crankshaft torque - not rear wheel torque which is the result of mutiplications from convertor, transmission, and rear axle ratio.
Horsepower is the result of that force applied over a period of time. So it's a function of crankshaft torque.

What you're saying is a horsepower number, because it represents the work of torque over a period of time, is the more "all encompassing" and therefore a more performance indicative figure.

Right?
 
ntsqd said:
This statement: is so ludicrous and wrong that I'm not even sure how to address it. Without torque you have no HP and nothing will get done. As I keep saying Torque is a measure of how much work can be done by the engine and HP is a measure of how fast the engine can do it. You need both, but how much of either depends on the use.
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True without Torque you don't have HP but without RPM you don't either eg.. how much hp does and non running 440 make lol. Torque is not the measurement of how much work can be done by an engine that's my point HP is, Torque is the how much force is produced in one power stroke that's it. And HP is not the measurement of how fast it can be done either RPM is. HP not Torque and or RPM is the measurement of how much work can be done by your engine which HP is the Sum ability of Torque and RPM.

Eg.. If your engine has a peak torque of 100 lbs ft all that mean your engine can hold 100 lbs in the air on a 1 foot bar without stalling not a great feat your arm is about two feet long so that's like holding a 50 lb bar bell in front of you I probably couldn't do it but some guys can. But the doesn't make him a 100 hp only if he could lift the bar bell like 5252 times a minute (RPM).

ntsqd said:
Gearing, tire size, and all of that has no bearing, that is Zero effect, on torque or HP produced. Mentioning that just confuses the issue and should be in a separate thread on how to apply what the engine produces.
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It has no effect on an engine on a engine dyno but does if you want to use the engine for anything, it's the power to the ground is what is important gears take torque and rpm (hp) and turn it into a use able function like forward motion.
 
famous bob said:
by the way, what`s the point of all this, does anybody really care? :banghead:
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I know it's seem like I'm arguing over semantics, but when your tell people to dump there 318/340 for a 360 or a 360 for a 408, maybe the bigger engine is or isn't the smartest choice for that person but they should be making that decision on the right info.

Personally I think if your willing to gear it build it if not go bigger. Personally I don't care if I got to run 5.13:1 when I'm done my 273, I can see with others that would be a deal breaker.
 
moper said:
Ah. I understand what you were aiming for now. Tell me if we're in agreement:
Torque is the twisting force. A measured empirical value for a given moment in time. For purposes of this dicussion it represents crankshaft torque - not rear wheel torque which is the result of mutiplications from convertor, transmission, and rear axle ratio.
Horsepower is the result of that force applied over a period of time. So it's a function of crankshaft torque.

What you're saying is a horsepower number, because it represents the work of torque over a period of time, is the more "all encompassing" and therefore a more performance indicative figure.

Right?
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Exactly but the period of time is RPM which is no more or less important than torque. When it come to HP that is :)
 
I think transmission matters too. If you have the same automatic after changing cams that require a much higher sweet spot, how the heck are you going to take advantage? Automatics with lots of torque is what you want on the street. Manuals are great, if you want to really get the juice out of the cam, street or strip.
 
Saying a 600hp motor is a 600hp motor no matter what the overall curve looks like before the peak is just plain WRONG. That is what you are really trying to say.
 
273 said:
I keep seeing people give misguided advise base on don't build engine A cause engine B will make more torque eg. . 340 vs 360 or 360 vs 408. For the most part torque is a useless number once HP curve is found from it.

There is a lot of reason to build HP at low rpm (torque engine) instead of high rpm thats why the factory kept going with larger engines over high rpm ones but a 400 hp engine is a 400 hp engine no matter if it's build with lots of torque at a low rpm or little torque at an high rpm both can do the same amount of work in the same amount of time eg... Accelerate your car (weight) in a certain amount of time ( E.T. ).

I think the problem is its easy for us to see HP and Torque as units of power or potential power but not RPM. But if you look at it like *this you want to move a 1000 tons of dirt a hundred miles away. And there's two trucks to do it (500 tons each) and one can move a 100 tons at 50 mph and the second truck can move 50 tons at a 100 mph. Both will move 500 tons in the same amount of time of 20 hrs but one will take 5 trips and the other 10 trips but both will do the same job. Trucks=engines......... Tons = torque....... Mph = rpm.........both are needed in some ratio to do the job moving 1000 tons a 100 miles in a certain amount of time 20hrs = Horsepower.

So when people ask about 318 vs 340/360, 340 vs 360 etc... Tell about gearing, stall speed, drive ability etc... Instead of 360 will make 30 lbs ft more than a 340 so a 340 is always doomed to lose cause it isn't true that's why they invent different gear ratios. And the main reason I wrote this a guy with a mild 360 wanted to know if his next step should be invest his money in the top end (heads) or bottom end (408 ) for more power and almost everyone agreed with the 408 and stock J heads instead of 360 and eddy rpm heads like it's magically gonna make more Power because it's larger.
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Old saying : HP wins Dyno Days, Torque wins races.
 
Hersbird said:
Saying a 600hp motor is a 600hp motor no matter what the overall curve looks like before the peak is just plain WRONG. That is what you are really trying to say.
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In general yes that's what I'm saying but in your instance the one with the overall better horsepower curve could be the better performer if the the car it set up right to take advantage. I'm making the assumption that both engines have same hp curves even though one is a high rpm small displacement engine and the other is a lower rpm large displacement engine. Your making the assumption that the bigger engine will have the better overall HP curve which isn't necessary true.
 
ntsqd said:
By your own definition HP is time-valued. Therefore HP is not work, it is work done over some time span. We see this in the calculation for HP; take the amount of work that can be done (torque) and multiply it by time (Revolutions Per Minute).
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Open any physics book and look up the definition of work. High school or college, which ever level you are at...


BASIC PHYSICS, my friend....
 
ProStocker273 said:
I have seen quite a few motors that don't cross hp and tq at 5252 rpm??
Though usually a race motor, but I've always heard they cross.
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No, you have not. If the curves do not cross at 5252RPM, the whole thing is bogus. It's that simple.
 
famous bob said:
lonewolf is right on this one! take your 400 horse 300 ft lbs of torque small block and put it in a 3800 lb car, then take a 500" big block and put it in that same car, changing nothing else, with equal traction, and see which one gets to the end of an 1/8 mile first.-been there done that---bob
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What would you rather have in a 3000lb car, assuming it is geared appropriately for each engine's powerband: 450HP/250lb/ft or 250HP/450lb/ft? For a 1/4 mile, the higher-HP car will win, each and every time.
 
Hersbird said:
Torque is king, a motor that makes 400 ft-lbs at 3000 rpm accelerates a car exactly the same as 400 ft-lbs at 6000 rpm even though the second is making twice the horsepower. So twice the horsepower but exactly the same force. Where the high HP is effective is if you make the torque early and hold it to those high rpms. But if you are just going to make 400 ft-lbs from say 2000-4000 or 4000-6000 they will perform the same even though one motor has much higher hp. So you are right you could put a ton of gear in the big hp motor and then drive around at 4000 rpm getting 3 mpg.
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No, wrong! The engine with 400lb/ft at 6000RPM is making exactly twice the horsepower as the one at 3000RPM! Repeat after me: one horsepower equals one horsepower!

This is junior-high-school physics.
 
Hersbird said:
No way the 600hp 340 wins over a 600hp 540 because while at one point they both make the same power, the 540 makes the power over a longer period of time. Granted the 540 may make so much power early in the rpms that it can't harness it to the ground but just building a motor for peak horsepower with no regard to overall rpm horsepower is not going to give you the quickest 1/4 mile times.
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Pablum. Plenty of people are running 8's with tiny, high-revving engines that make (maybe) 250lb/ft. But they make big HORSEPOWER, because they wind to 10,000+RPM.

Also note: this car has a tiny 4-banger in it!

JonHuber_DragWeekWin09.jpg


It runs 8's in race trim, low 9's in street trim. And yes, it IS a STREET car!
 
273 said:
True without Torque you don't have HP but without RPM you don't either eg.. how much hp does and non running 440 make lol. Torque is not the measurement of how much work can be done by an engine that's my point HP is, Torque is the how much force is produced in one power stroke that's it. And HP is not the measurement of how fast it can be done either RPM is. HP not Torque and or RPM is the measurement of how much work can be done by your engine which HP is the Sum ability of Torque and RPM.

Eg.. If your engine has a peak torque of 100 lbs ft all that mean your engine can hold 100 lbs in the air on a 1 foot bar without stalling not a great feat your arm is about two feet long so that's like holding a 50 lb bar bell in front of you I probably couldn't do it but some guys can. But the doesn't make him a 100 hp only if he could lift the bar bell like 5252 times a minute (RPM).



It has no effect on an engine on a engine dyno but does if you want to use the engine for anything, it's the power to the ground is what is important gears take torque and rpm (hp) and turn it into a use able function like forward motion.
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Based on my more than a decade of working on, around, and designing dyno cells and over 40 years of working around engines as a whole, on top of earning an engineering degree, you're wrong about all of that. We'll have to agree to disagree, because clearly you're not interested in what I and others have been saying. You're only interested in promoting your own erroneous point of view. After 3 pages of no movement on your part in spite of the overwhelming contrary info, this thread is not a discussion or a debate, it's sham.
 
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