Torque vs Horsepower - VERY impressive commentary

[Fiddler's Gold]

EDIT: The article in this first post of this thread has since been updated and the updated version can be found in Post #22. If you wish to go directly to the updated post, follow this link - http://www.corvetteactioncenter.com...very-impressive-commentary-2.html#post1087272

Jane Ann
XLR8
Forums Administration
Corvette Action Center

************************************************************************************

I was searching for some more info on my gearing options and stumbled up this extremely well-written message thread with notes for the L98 and LT1 engines. The HP vs. Torque explanations in both "CARLAND" and commonplace lingo is well-appreciated. I hope you enjoy this as much as I did. Much respect out to the original author.

HTH,
The Fiddler

Torque vs. HP -
--------------------------------------------------------------------------------

Horsepower and Torque (In-Depth)
Date: Sun, 31 Jan 1999 17:19:12 -0500
From: Bruce Augenstein <Bruce.Augenstein@digital.com>
Subject: Horsepower and Torque - a Primer (part 1)

There's been a certain amount of discussion, in this and other files, about
the concepts of horsepower and torque, how they relate to each other, and
how they apply in terms of automobile performance. I have observed that,
although nearly everyone participating has a passion for automobiles, there
is a huge variance in knowledge. It's clear that a bunch of folks have
strong opinions (about this topic, and other things), but that has generally
led to more heat than light, if you get my drift . This is meant to be a
primer on the subject.

OK. Here's the deal, in moderately plain English.

Force, Work and Time

If you have a one pound weight bolted to the floor, and try to lift it with
one pound of force (or 10, or 50 pounds), you will have applied force and
exerted energy, but no work will have been done. If you unbolt the weight,
and apply a force sufficient to lift the weight one foot, then one foot
pound of work will have been done. If that event takes a minute to
accomplish, then you will be doing work at the rate of one foot pound per
minute. If it takes one second to accomplish the task, then work will be
done at the rate of 60 foot pounds per minute, and so on.

In order to apply these measurements to automobiles and their performance
(whether you're speaking of torque, horsepower, newton meters, watts, or any
other terms), you need to address the three variables of force, work and
time.

Awhile back, a gentleman by the name of Watt (the same gent who did all that
neat stuff with steam engines) made some observations, and concluded that
the average horse of the time could lift a 550 pound weight one foot in one
second, thereby performing work at the rate of 550 foot pounds per second,
or 33,000 foot pounds per minute, for an eight hour shift, more or less. He
then published those observations, and stated that 33,000 foot pounds per
minute of work was equivalent to the power of one horse, or, one horsepower.


Everybody else said OK.

For purposes of this discussion, we need to measure units of force from
rotating objects such as crankshafts, so we'll use terms which define a
*twisting* force, such as foot pounds of torque. A foot pound of torque is
the twisting force necessary to support a one pound weight on a weightless
horizontal bar, one foot from the fulcrum.

Now, it's important to understand that nobody on the planet ever actually
measures horsepower from a running engine on a standard dynomometer. What we
actually measure is torque, expressed in foot pounds (in the U.S.), and then
we *calculate* actual horsepower by converting the twisting force of torque
into the work units of horsepower.

Visualize that one pound weight we mentioned, one foot from the fulcrum on
its weightless bar. If we rotate that weight for one full revolution against
a one pound resistance, we have moved it a total of 6.2832 feet (Pi * a two
foot circle), and, incidently, we have done 6.2832 foot pounds of work.

OK. Remember Watt? He said that 33,000 foot pounds of work per minute was
equivalent to one horsepower. If we divide the 6.2832 foot pounds of work
we've done per revolution of that weight into 33,000 foot pounds, we come up
with the fact that one foot pound of torque at 5252 rpm is equal to 33,000
foot pounds per minute of work, and is the equivalent of one horsepower. If
we only move that weight at the rate of 2626 rpm, it's the equivalent of 1/2
horsepower (16,500 foot pounds per minute), and so on.
Therefore, the following formula applies for calculating horsepower from a
torque measurement:

Torque * RPM
Horsepower = ------------
5252

This is not a debatable item. It's the way it's done. Period.

The Case For Torque

Now, what does all this mean in carland?

First of all, from a driver's perspective, torque, to use the vernacular,
RULES . Any given car, in any given gear, will accelerate at a rate that
*exactly* matches its torque curve (allowing for increased air and rolling
resistance as speeds climb). Another way of saying this is that a car will
accelerate hardest at its torque peak in any given gear, and will not
accelerate as hard below that peak, or above it. Torque is the only thing
that a driver feels, and horsepower is just sort of an esoteric measurement
in that context. 300 foot pounds of torque will accelerate you just as hard
at 2000 rpm as it would if you were making that torque at 4000 rpm in the
same gear, yet, per the formula, the horsepower would be *double* at 4000
rpm. Therefore, horsepower isn't particularly meaningful from a driver's
perspective, and the two numbers only get friendly at 5252 rpm, where
horsepower and torque always come out the same.

In contrast to a torque curve (and the matching pushback into your seat),
horsepower rises rapidly with rpm, especially when torque values are also
climbing. Horsepower will continue to climb, however, until well past the
torque peak, and will continue to rise as engine speed climbs, until the
torque curve really begins to plummet, faster than engine rpm is rising.
However, as I said, horsepower has nothing to do with what a driver *feels*.


You don't believe all this?

Fine. Take your non turbo car (turbo lag muddles the results) to its torque
peak in first gear, and punch it. Notice the belt in the back? Now take it
to the power peak, and punch it. Notice that the belt in the back is a bit
weaker? Fine. Can we go on, now?
(part two follows)

------------------------------

Date: Sun, 31 Jan 1999 17:19:24 -0500
From: Bruce Augenstein <Bruce.Augenstein@digital.com>
Subject: Horsepower and Torque - a Primer (part 2)

The Case For Horsepower

OK. If torque is so all-fired important (and feels so good), why do we care
about horsepower?

Because (to quote a friend), "It is better to make torque at high rpm than
at low rpm, because you can take advantage of *gearing*.

For an extreme example of this, I'll leave carland for a moment, and
describe a waterwheel I got to watch awhile ago. This was a pretty massive
wheel (built a couple of hundred years ago), rotating lazily on a shaft
which was connected to the works inside a flour mill. Working some things
out from what the people in the mill said, I was able to determine that the
wheel typically generated about 2600(!) foot pounds of torque. I had clocked
its speed, and determined that it was rotating at about 12 rpm. If we hooked
that wheel to, say, the drive wheels of a car, that car would go from zero
to twelve rpm in a flash, and the waterwheel would hardly notice .

On the other hand, twelve rpm of the drive wheels is around one mph for the
average car, and, in order to go faster, we'd need to gear it up. If you
remember your junior high school physics and the topic of simple machines,
you'll remember that to gear something up or down gives you linear increases
in speed with linear decreases in force, or vice versa. To get to 60 miles
per hour would require gearing the output from the wheel up by 60 times,
enough so that it would be effectively making a little over 43 foot pounds
of torque at the output (one sixtieth of the wheel's direct torque). This
is not only a relatively small amount, it's less than what the average car
would need in order to actually get to 60. Applying the conversion formula
gives us the facts on this. Twelve times twenty six hundred, over five
thousand two hundred fifty two gives us:

6 HP.

Oops. Now we see the rest of the story. While it's clearly true that the
water wheel can exert a *bunch* of force, its *power* (ability to do work
over time) is severely limited.

At The Dragstrip

OK. Back to carland, and some examples of how horsepower makes a major
difference in how fast a car can accelerate, in spite of what torque on your
backside tells you .

A very good example would be to compare the LT1 Corvette (built from 1992
through 1996) with the last of the L98 Vettes, built in 1991. I'm sorry to
mention the "C" word amongst this august group, but there just isn't a
better example to use. Figures as follows:


Engine Peak HP @ RPM Peak Torque @ RPM
------ ------------- -----------------
L98 250 @ 4000 340 @ 3200
LT1 300 @ 5000 340 @ 3600

The cars are geared identically, and car weights are very nearly identical,
so it's a good comparison.

First, each car will push you back in the seat (the fun factor) with the
same authority - at least at or near peak torque in each gear. One will tend
to *feel* about as fast as the other to the driver, but the LT1 will
actually be significantly faster than the L98, even though it won't pull any
harder. If we mess about with the formula, we can begin to discover exactly
*why* the LT1 is faster. Here's another slice at that formula:

Horsepower * 5252
Torque = -----------------
RPM
If we plug some numbers in, we can see that the L98 is making 328 foot
pounds of torque at its power peak (250 hp @ 4000), and we can infer that it
cannot be making any more than 263 pound feet of torque at 5000 rpm, or it
would be making more than 250 hp at that engine speed, and would be so
rated. In actuality, the L98 is probably making no more than around 210
pound feet or so at 5000 rpm, and anybody who owns one would shift it at
around 46-4700 rpm, because more torque is available at the drive wheels in
the next gear at that point.

On the other hand, the LT1 is fairly happy making 315 pound feet at 5000
rpm, and is happy right up to its mid 5s redline.

So, in a drag race, the cars would launch more or less together. The L98
might have a slight advantage due to its peak torque occurring a little
earlier in the rev range, but that is debatable, since the LT1 has a wider,
flatter curve (again pretty much by definition, looking at the figures).
>From somewhere in the mid range and up, however, the LT1 would begin to pull
away. Where the L98 has to shift to second (and give up some torque
multiplication for speed, a la the waterwheel), the LT1 still has around
another 1000 rpm to go in first, and thus begins to widen its lead, more and
more as the speeds climb. As long as the revs are high, the LT1, by
definition, has an advantage.

There are numerous examples of this phenomenon. The Integra GS-R, for
instance, is faster than the garden variety Integra, not because it pulls
particularly harder (it doesn't), but because it pulls *longer*. It doesn't
feel particularly faster, but it is. (part three follows)

------------------------------

Date: Sun, 31 Jan 1999 17:19:34 -0500
From: Bruce Augenstein <Bruce.Augenstein@digital.com>
Subject: Horsepower and Torque - a Primer (part 3)

A final example of this requires your imagination. Figure that we can tweak
an LT1 engine so that it still makes peak torque of 340 foot pounds at 3600
rpm, but, instead of the curve dropping off to 315 pound feet at 5000, we
extend the torque curve so much that it doesn't fall off to 315 pound feet
until 15000 rpm. OK, so we'd need to have virtually all the moving parts
made out of unobtanium , and some sort of turbo charging on demand that
would make enough high-rpm boost to keep the curve from falling, but hey,
bear with me.

If you raced a stock LT1 with this car, they would launch together, but,
somewhere around the 60 foot point, the stocker would begin to fade, and
would have to grab second gear shortly thereafter. Not long after that,
you'd see in your mirror that the stocker has grabbed third, and not too
long after that, it would get fourth, but you'd wouldn't be able to see that
due to the distance between you as you crossed the line, *still in first
gear*, and pulling like crazy.

I've got a computer simulation that models an LT1 Vette in a quarter mile
pass, and it predicts a 13.38 second ET, at 104.5 mph. That's pretty close
(actually a tiny bit conservative) to what a stock LT1 can do at 100% air
density at a high traction drag strip, being powershifted. However, our
modified car, while belting the driver in the back no harder than the
stocker (at peak torque) does an 11.96, at 135.1 mph - all in first gear, of
course. It doesn't pull any harder, but it sure as hell pulls longer .
It's also making 900 hp, at 15,000 rpm.

Of course, folks who are knowledgeable about drag racing are now openly
snickering, because they've read the preceeding paragraph, and it occurs to
them that any self respecting car that can get to 135 mph in a quarter mile
will just naturally be doing this in less than ten seconds. Of course that's
true, but I remind these same folks that any self-respecting engine that
propels a Corvette into the nines is also making a whole bunch more than 340
foot pounds of torque.

That does bring up another point, though. Essentially, a more "real"
Corvette running 135 mph in a quarter mile (maybe a mega big block) might be
making 700-800 foot pounds of torque, and thus it would pull a whole bunch
harder than my paper tiger would. It would need slicks and other
modifications in order to turn that torque into forward motion, but it would
also get from here to way over there a bunch quicker.

On the other hand, as long as we're making quarter mile passes with fantasy
engines, if we put a 10.35:1 final-drive gear (3.45 is stock) in our fantasy
LT1, with slicks and other chassis mods, we'd be in the nines just as easily
as the big block would, and thus save face . The mechanical advantage of
such a nonsensical rear gear would allow our combination to pull just as
hard as the big block, plus we'd get to do all that gear banging and such
that real racers do, and finish in fourth gear, as God intends.

The only modification to the preceding paragraph would be the rotational
moments of inertia (flywheel effect) argument brought about by such a stiff
rear gear, and that argument is outside of the scope of this already massive
document. Another time, maybe, if you can stand it .

At The Bonneville Salt Flats

Looking at top speed, horsepower wins again, in the sense that making more
torque at high rpm means you can use a stiffer gear for any given car speed,
and thus have more effective torque *at the drive wheels*.

Finally, operating at the power peak means you are doing the absolute best
you can at any given car speed, measuring torque at the drive wheels. I
know I said that acceleration follows the torque curve in any given gear,
but if you factor in gearing vs. car speed, the power peak is *it*. A BMW
example will illustrate this.

At the 4250 rpm torque peak, a 3 liter E36 M3 is doing about 57 mph in third
gear, and, as mentioned previously, it will pull the hardest in that gear at
that speed when you floor it, discounting wind and rolling resistance. In
point of fact (and ignoring both drive train power losses and rotational
inertia), the rear wheels are getting 1177 foot pounds of torque thrown at
them at 57 mph (225 foot pounds, times the third gear ratio of 1.66:1, times
the final drive ratio of 3.15:1), so the car will bang you back very nicely
at that point, thank you very much.

However, if you were to regear the car so that it is at its power peak at 57
mph, you'd have to change the final drive ratio to approximately 4.45:1.
With that final drive ratio installed, you'd be at 6000 rpm in third gear,
where the engine is making 240 hp. Going back to our trusty formula, you can
ascertain that the engine is down to 210 foot pounds of torque at that
point(240 times 5252, divided by 6000), but if you do the arithmetic (210
foot pounds, times 1.66, times the 4.45), you can see that you are now
getting 1551 foot pounds of torque at the rear wheels, making for a nearly
32% more satisfying belt in the back.

Any other rpm (other than the power peak) at a given car speed will net you
a lower torque value at the drive wheels. This would be true of any car on
the planet, so, theoretical "best" top speed will always occur when a given
vehicle is operating at its power peak.

"Modernizing" The 18th Century

OK. For the final-final point (Really. I Promise.), what if we ditched that
water wheel, and bolted a 3 liter E36 M3 engine in its place? Now, no 3
liter BMW is going to be making over 2600 foot pounds of torque (except
possibly for a single, glorious instant, running on nitromethane), but,
assuming we needed 12 rpm for an input to the mill, we could run the BMW
engine at 6000 rpm (where it's making 210 foot pounds of torque), and gear
it down to a 12 rpm output, using a 500:1 gear set. Result? We'd have
*105,000* foot pounds of torque to play with. We could probably twist the
whole flour mill around the input shaft, if we needed to .

The Only Thing You Really Need to Know

Repeat after me. "It is better to make torque at high rpm than at low rpm,
because you can take advantage of *gearing*."
​

 

[Vettelt193]

Good article, I wished it covered a bit more on the seat of the pants feeling.... LT1's make their power so high, that they don't feel as powerful and from real world experience, the L98 has a huge advantage over the LT1 off the line... but, just like it explains in the aritcle, get the cars moving and the LT1 can pull away.

 

[warren s]

I hear about the "bottom end" power of the L98 so often but in real world experiance the L98 cars I have driven and just been in, were actually slower than LT1 powered vehicles of similier body style (vette, fbird, camaro)

 

[Vettelt193]

LT1's are faster... but off the line, L98 cars are amazing.... My old vette, a '93 LT1 6-speed, would get spanked off the line by L98 cars all the time... these L98's were close to stock... I would always blow by them at the end of the track and win, but for a street car, I think the L98 is hands down a better car... who needs to have a ton of horsepower at high RPM when you use from idle to about 2000 RPM 95% of the time? There is a friend of mine with a 1990 auto L98. He took me every time off the line and through the 1/8th mile.... He even beat me with his A/C on because he forgot to turn it off! I really thought my Dad's '98 Pace Car had a better low end than my LT1 car, so I took that to the track one day... He spanked me off the line in that too... I truly believe in:

"Horsepower moves cars off the lot, Torque moves cars."

When I was younger, I could never figure out why my '87 convertible ran so much better off the line than my Mom's '93... both were automatic, my car had less HP, and weighed more... I enjoyed the L98 more, because it had a very usable power range.

 

[Fiddler's Gold]

Yep Yep Yep

I agree with ya, Vettelt193 - Perhaps Warren had some either bad experiences with some particular L98s or perhaps some poor drivers if he was the passenger seat. I am super pleased with my extensively modified L98 and I am firmly convinced that it could take most anything off of the line even with the current high gear ratios (setup for SCCA) with almost no exception. Torque is truly what moves you --- nothing else. L98 is the torque monster for a reason and my configuration and systemic racing-inspired rebuild just emphasizes that ideal. I admit that some LTs are fabulous engines, but for the bang to the buck with regards to low-end torque and <2500RPM utilization not much comes close to a matched L98.

My $.02
-=Andy=-

 

[Nick Papagiorgio]

The Plain Truth about Bruce Augenstein’s Explanation of Torque and Power

The Plain Truth about Bruce Augenstein’s Explanation of Torque and Power
- Nick Papagiorgio

This article by Bruce Augenstein has been popped all over the web over the past decade or so, all by people who mean well, but who, like Augenstein, would not know a proper explanation of torque and power from a pile of horse manure if their lives depended on it.

To make acceleration as great as you can make it at any given instant, you have to make power, not engine torque per se, as great as you can make it. The reason is that at each given instant, acceleration equates to actual power divided by the product of mass and velocity. Because these genuine facts are the true essence of the correct understanding of this subject, legitimate explanations focus expressly on these facts.

Near the start, Bruce Augenstein wrote this:

“The Case for Torque - First of all, from a driver's perspective, torque, to use the vernacular, RULES . Any given car, in any given gear, will accelerate at a rate that *exactly* matches its torque curve … Torque is the only thing that a driver feels, and horsepower is just sort of an esoteric measurement in that context. 300 foot pounds of torque will accelerate you just as hard at 2000 rpm as it would … at 4000 rpm in the same gear, yet … the horsepower would be *double* at 4000 rpm. Therefore, horsepower isn't particularly meaningful from a driver's perspective, and the two numbers only get friendly at 5252 rpm, where horsepower and torque always come out the same. … In contrast to a torque curve (and the matching pushback into your seat), horsepower rises rapidly with rpm. ... However ... horsepower has nothing to do with what a driver *feels*. … You don't believe all this? Fine. Take your non turbo car (turbo lag muddles the results) to its torque peak in first gear, and punch it. Notice the belt in the back? Now take it to the power peak, and punch it. Notice that the belt in the back is a bit weaker? Fine. Can we go on, now? ”
​

No person who has a decent grasp of elementary physics would ever, ever claim that power “has nothing to do with what a driver feels” and is “just sort of an esoteric measurement”, etc. We desire to know exactly how acceleration depends on engine torque and exactly how acceleration depends on power, but it is imperative that this understanding be rooted in the instantaneous perspective. Augenstein fixated instead on what happens “in any given gear”, and his inferences, regarding those dependencies, are asinine. The substantive fact is that whenever power is the same for two different gears at some instant, acceleration is likewise the same, even though the engine speeds are different. Whenever engine torque is the same for two different gears at some instant, there are two different values of acceleration, and they are in the same ratio as the two different engine speeds and the two different amounts of power. Thus, a given amount of power has essentially the same significance no matter the engine speed, whereas the significance of a given amount of engine torque depends fundamentally on engine speed. This fact is the essence of the correct understanding of this subject. But Augenstein asserts essentially the opposite, and that is asinine.

He has an alternative theory for how power matters:

“… some examples of how horsepower makes a major difference in how fast a car can accelerate, in spite of what torque on your backside tells you .”
​

How could power possibly make a “major difference” in how fast a car can accelerate and yet have nothing to do with what you feel “on your backside”? He believes that the force that you sense “on your backside” is related to torque in an intimate, primary manner, and that power simply has no relevance to this force. This belief is unimaginably naive. And it is patently nonsensical. Yet, there can be no doubt that this is the driving principle in his understanding of this subject.

“A very good example would be to compare the current LT1 Corvette with the last of the L98 Vettes, built in 1991. … The cars are geared identically …. First, each car will push you back in the seat … with the same authority - at least at or near peak torque in each gear. One will tend to *feel* about as fast as the other to the driver, but the LT1 will … be significantly faster than the L98, even though it won't pull any harder. …. Where the L98 has to shift to second (and throw away torque multiplication for speed), the LT1 still has around another 1000 rpm to go in first, and thus begins to widen its lead ... Another example would be the LT1 against the ZR-1. Same deal, only in reverse. The ZR-1 actually pulls a little harder than the LT1... The real advantage, however, is that the ZR-1 has another 1500 rpm in hand at the point where the LT1 has to shift….There are numerous examples of this phenomenon. The Integra GS-R, for instance, is faster than the garden variety Integra, not because it pulls particularly harder (it doesn't), but because it pulls *longer*...”
​

In its original form, this section made up nearly half of the full article. In case it isn’t apparent, his point is that greater power yields the ability to “pull longer” but not the ability to “pull harder”. This is his understanding of how power matters. It ties in to his central belief that power has nothing to do with what you feel. His “pull longer” effect is contrived and illusory. His made-up understanding of how power matters controverts the true understanding of how power matters, and does so overtly. The true reason that power matters is that acceleration always is in proportion with actual power. The true significance of power resides wholly within this one inordinately simple fact, which fact quite obviously means that greater power yields the ability to “pull harder”.

As for pulling harder, the vehicle with the greater peak value for the ratio of actual power to vehicle speed will absolutely exhibit greater peak acceleration, i.e., will pull hardest. (Assuming equal mass of course.) If you apply the constraint for the wheel sizes to be identical, it then becomes correct to say that this will always be the vehicle with greater peak wheel torque. But not even with that constraint is it correct to say that this will always be the vehicle with greater peak engine torque.

Near the start of the article, he attempted to explain the physical concept of power. There, he made several novice errors in his interpretations of force, work and power. Right in the middle of that, he wrote this:

“Now, it's important to understand that nobody on the planet ever actually measures horsepower from a running engine. What we actually measure (on a dynomometer) is torque, expressed in foot pounds (in the U.S.), and then we *calculate* actual horsepower ...”
​

Who thinks this stuff up? This notion, that torque is “actually” measured and that power is just a calculated value, is sheer bunk. Orthodox science expressly rejects the notion of a meaningful distinction between measurements that are taken “actually” vs. derived. This distinction is contrived. Besides, brake dynamometers can use the rheostatic type of brake, in which case power equates to the product of voltage and current at the resistor that dissipates the energy. With the inertial type of dynamometer, power can be inferred from the drum’s angular acceleration and its moment of inertia.

Then we come to his waterwheel anecdote. It was not incorrect, but neither was it at all coherent. He talked about hooking the waterwheel to a car. Ostensibly he said that if you apply gearing to the waterwheel to step up the rotational speed, you end up with a meager amount of torque and that this has something to do with the meager amount of power. The key fact, without which none of it holds together, is that power is not altered by the gearing (except for frictional loss). It is this fact that tells you that for each doubling of rotational speed, torque decreases by one-half (and vice-versa). He produced a value for torque at the output but did not explain that to obtain that value, he made direct use of the fact that power at the output is nominally the same as power at the input. This fact is crucial to the proper understanding of this subject, but he never once mentioned this fact, anywhere in the article.

The high point was near the end of the article, where he wrote that the power peak is the best possible engine speed, which is correct of course. But that paragraph was incongruent with most of the rest of what he wrote, and it came across like an afterthought, as though it was an anomaly and of secondary importance relative to the other notions that he had expounded. It dealt expressly with the power peak, and he still did not say plainly that acceleration is proportional to power. He also wrapped that explanation around the idea of swapping out the transmission, which strikes me as odd considering that the facts being explained are fully manifested in the ordinary task of gear selection. Why didn’t he say simply that if power is twice greater in 2nd gear than in 4th gear at some arbitrary instant, that the same will be true for acceleration?

He summarized by writing, for the second time in the article, this:

“The Only Thing You Really Need to Know - Repeat after me. It is better to make torque at high rpm than at low rpm, because you can take advantage of *gearing*. ”
​

This torque-obsessed perspective is just plain silly. It says essentially nothing, because it says nothing about just how high the engine speed should be set, in order to maximize acceleration. This silly perspective also says in effect that gearing is the reason that acceleration is linearly coupled to power.

An explanation that expounds a significant amount of bunk is fundamentally bogus no matter how many legitimate facts are mixed in to create the appearance otherwise. In a few places Augenstein bumped into the bona fide facts that are the true essence of the correct understanding of the subject. But he did not ever say in any plain, direct manner that acceleration is proportional to power. Nor did he explain that power is nominally the same at the wheel as at the engine. Nor did he explain that instantaneously, each unique value of wheel torque is uniquely associated with a unique value of power, but not so with a unique value of engine torque. Instead of discussing these meaningful facts, he expounded a bunch of nonsense. He emphatically asserted that “Torque is the only thing that a driver feels”, and that “horsepower isn’t particularly meaningful from a driver’s perspective.” These statements do not make a scintilla of proper sense. He argued at length that only torque has anything to do with how hard an engine pulls and that power only influences how long the engine pulls in each gear. He even asserted that no person on the planet ever measures power. All of this is hogwash, and this is what the article mainly consists of. The bulk of what he wrote is utter nonsense. This is the plain truth, and anyone who would deny this is either incredibly naive or else exceedingly stubborn and probably much the same as Augenstein. It is all but certain that he has never taken a proper classroom course in physics in his entire life. All he really did was to spew a bunch of concocted nonsense that controverts the correct, orthodox understanding of the subject. There are lots of people who obviously do not realize this, and that is pretty sad, because it could not be more apparent than it is.

 

[boomdriver]

I'm not real sure why the debate is still on. Perhaps because torque and/or horsepower have not been properly defined?

I'll do that for everyone in the simplest terms so that there is no need for any confusion...

"torque" can only come from a rotating assembly, a shaft that is turning. Torque is the measured ability of a shaft to turn or rotate. Ex: a shaft can turn quickly, but if you can grab it and stop its rotation is has very little torque. If that same same shaft resist stopping, then it has a measurable amount of torque that we refer to in lbs/ft. How much load (lbs, resistance) there is over a given distance (feet) or more commonly known as ft/lbs.

horsepower is the ability to maintain resistance against an applied load. HP is the ability to overcome resistance. This is also measured in terms of how much "work" that a farm animal can do. It is not exact, and it varies with conditions.Is your cars engine compared to a Clydesdale, or a Shetland Pony? HP is relative. Torque is definate.

Simply stated, torque is the ability to wind up the anchor chain on a big ship. HP is the ability to hold that load in place.

Torque is being able to start your car moving up a hill, To accellerate,. while HP is the ability to maintain that rate of climb. Torque takes you to 100 mph. HP allows you to stay there.

Torque is what "gets you moving" and HP is what "keeps you moving". Subtle difference but a real diference.

See? Easy.

BTW..

the analogy of the L98 vs the LT is a drag race is a poor one. Being able to upshift and get into a higher gear sooner, is just as much an advantage as being able to run out a gear further. I have yet to see what an LT looks like from behind........unless it was parked.

 

[TedC]

LT1's are faster... but off the line, L98 cars are amazing.... My old vette, a '93 LT1 6-speed, would get spanked off the line by L98 cars all the time... these L98's were close to stock... I would always blow by them at the end of the track and win, but for a street car, I think the L98 is hands down a better car... who needs to have a ton of horsepower at high RPM when you use from idle to about 2000 RPM 95% of the time? There is a friend of mine with a 1990 auto L98. He took me every time off the line and through the 1/8th mile.... He even beat me with his A/C on because he forgot to turn it off! I really thought my Dad's '98 Pace Car had a better low end than my LT1 car, so I took that to the track one day... He spanked me off the line in that too... I truly believe in:

"Horsepower moves cars off the lot, Torque moves cars."

When I was younger, I could never figure out why my '87 convertible ran so much better off the line than my Mom's '93... both were automatic, my car had less HP, and weighed more... I enjoyed the L98 more, because it had a very usable power range.

Spot on!!! I have NEVER been beaten by any stock LT1 off the line with my stock L98. In the past I posted some real life results on this forum. From my experiences a good running stock L98 is faster in the first 1/8 mile than a good running stock LT1. After the first 1/8 mile it is all LT1. LT1s run better with manuals and the L98 is dumb and happy with an automatic. Too bad GM decided not to performance tune the TPI intake system for the larger 350 engine. I think they could of pulled out another 25 HP, improved upper RPM performance, and maintained most of the low end tree pulling torque.

 

[Tuna]

I've always heard that HP determines top speed or trap speed while TORQUE determines acceleration.
Seems to hold true.

 

[Nick Papagiorgio]

What's to debate

I'm not real sure why the debate is still on. Perhaps because torque and/or horsepower have not been properly defined?

There is no debate so far as I am concerned. There isn't anything to debate. It is simply that the article that Augenstein wrote is mainly nonsense, and whenever it pops up anywhere on the web, as it did here, it is appropriate for someone to wave their hand and state openly and plainly, with no qualms, that it is nonsense.

I'll do that for everyone in the simplest terms so that there is no need for any confusion... "torque" can only come from a rotating assembly, a shaft that is turning. Torque is the measured ability of a shaft to turn or rotate. Ex: a shaft can turn quickly, but if you can grab it and stop its rotation is has very little torque. If that same same shaft resist stopping, then it has a measurable amount of torque that we refer to in lbs/ft. How much load (lbs, resistance) there is over a given distance (feet) or more commonly known as ft/lbs.

I have never understood why it is that so many who so obviously have never once actually taken a classroom course in physics are so quick to want to explain torque and power. You first say that torque can only come from a rotating assembly. That is correct if you are talking about the net torque. It is the same as with force. If an object is not moving, the total, net force on it is zero. There can be several individual forces, but the aggregate has to be zero, lest there be acceleration. For example, when you are standing on the floor, there is the force of gravity and also the contact force that you feel on the soles of your feet. They cancel, and the net force is zero. It is essentially the same with torque. When you attempt to loosen a tight nut but are not able to budge it, you do apply torque, but there is also a torque that resists your effort. It is due to friction, and assuming that there is no motion, the net torque is zero. If there is uniform, non-accelerating rotational motion, then there is zero net torque notwithstanding that there is movement.

horsepower is the ability to maintain resistance against an applied load. HP is the ability to overcome resistance. This is also measured in terms of how much "work" that a farm animal can do. It is not exact, and it varies with conditions.Is your cars engine compared to a Clydesdale, or a Shetland Pony? HP is relative. Torque is definate.

Horsepower is a unit of measure used to express quantities of power. One good indication of whether someone who talks about torque and power really knows what they are talking about is whether they say "power" or say "horsepower" where they should say "power". I have yet to meet someone who had ever studied physics who use the word "horsepower" except expressly as a unit of measure, i.e., when giving a value in Hp. As for what power is, power is simply the instantaneous rate at which work is being performed. Equivalently, it is the instantaneous rate at which energy is being expended. These are the only two correct definitions for power. Any attempt to define power any other way amount to a contrivance that will likely lead to all sorts of silly perceptions. For example, you have somehow arrived at the ridiculous notion that power is relative and that torque is definite. You could try from now until hell freezes over to explain exactly what you mean by that, but it would, never make a whit of sense.

Simply stated, torque is the ability to wind up the anchor chain on a big ship. HP is the ability to hold that load in place.

That's simple alright, but there is not one scintilla of substantive correctness to it. When the anchor is lifted, work is being performed. Power at any instant is the instantaneous rate at which work is being performed. As long as the anchor is moving and there is either acceleration or friction, there is also power.

Torque is being able to start your car moving up a hill, To accellerate,. while HP is the ability to maintain that rate of climb. Torque takes you to 100 mph. HP allows you to stay there. Torque is what "gets you moving" and HP is what "keeps you moving". Subtle difference but a real diference. See? Easy.

There isn't any point in beating around the bush here. What you wrote there is utterly ridiculous. What was the reason that you thought that you understood anything at all about this? I know for certain that you did not read anything remotely similar to that in any legitimate text book. So where did you come up with this? Why do you think that there is any substantive truth to this? There is none whatsoever. It is ridiculous.

BTW.. the analogy of the L98 vs the LT is a drag race is a poor one. Being able to upshift and get into a higher gear sooner, is just as much an advantage as being able to run out a gear further. I have yet to see what an LT looks like from behind........unless it was parked.

That whole lengthy section in Augenstein's ridiculous article does not shed one iota of correct light on torque and power, and neither does the comment that you added to that horrifically specious section of that horrifically specious article.

 

[Nick Papagiorgio]

And where exactly did you hear that??

I've always heard that HP determines top speed or trap speed while TORQUE determines acceleration. Seems to hold true.

Stop listening to whoever told you that. There is no truth to that whatsoever. At any given instant, acceleration equates to actual power divided by the product of mass and velocity. That is a substantive fact. Neither torque nor power determines acceleration, at least not per the proper meaning of the word "determines". There are various different equations that you can write, that substantively relate torque to acceleration, and that substantively relate power to acceleration. In either case, there are other quantities, most notably mass, that enter into those equations. The simplest and most generally useful among such equations is the one that says that acceleration equates to power divided by the product of mass and velocity. As for top speed, acceleration gradually comes to zero as the total force of friction increases and becomes as great as vehicle thrust. Aerodynamic drag is the predominant friction, and it increases as the square of vehicle speed. When equilibrium is reached, thrust is in balance with total friction. Thrust equates to wheel torque divided by wheel radius. You can of course use the overall gear ratio to express wheel torque in terms of engine torque. But thrust also equates to power divided by vehicle speed, which means that when equilibrium is reached, power is in equilibrium with the product of vehicle speed and total friction.

 

[Nick Papagiorgio]

Spot on!!! I have NEVER been beaten by any stock LT1 off the line with my stock L98. In the past I posted some real life results on this forum. From my experiences a good running stock L98 is faster in the first 1/8 mile than a good running stock LT1. After the first 1/8 mile it is all LT1. LT1s run better with manuals and the L98 is dumb and happy with an automatic. Too bad GM decided not to performance tune the TPI intake system for the larger 350 engine. I think they could of pulled out another 25 HP, improved upper RPM performance, and maintained most of the low end tree pulling torque.

I quoted TedC's comment, but the comment I want to make here is in regards to the earlier comment that he quoted, i.e., this: "Horsepower moves cars off the lot, Torque moves cars." There isn't anything wrong with cute catch phrases of this sort, and I tend to enjoy them. But you have to be careful, because in the context of that comment, horsepower refers to the peak power, and torque refers to the peak torque. It becomes necessary to keep clear exactly what the question is that is being addressed, i.e., whether the question asks whether the peak power per se vs. peak torque per se is more meaningful, or whether the question is asking about how acceleration at a given instant is substantively related to actual torque and to actual power at that instant. An article that gives a correct, substantive explanation of torque and power is not expressly concerned with that other debate that is concerned with peak power vs. peak torque. Ultimately a substantively correct article will shed lots of light on the significance of peak torque and peak power, but first and foremost it is concerned with the substantive manner in which actual torque and actual power at a given, arbitrary instant are concerned with acceleration at that instant. This is something that Augenstein did not realize, and the fact that he did not realize even this much says a whole lot about his article.

 

[geekinavette]

:L Wow came here just for that.

 

[LLC5]

:L Wow came here just for that.

Apparently.

Not to mention the revival of a 9 year old post.

 

[geekinavette]

Apparently.

Not to mention the revival of a 9 year old post.

Didn't even notice that!

 

[muddywaters]

That's more than I need to know, Now my head hurts.otfl

 

[Nick Papagiorgio]

Ever do a Web search??

Apparently.

Not to mention the revival of a 9 year old post.

The reasons for my refuting Augenstein's junk article were sound and were indifferent to the date of the original post. Anyone who does a web search for "torque power" will easily encounter the article. If I had my way, the thread along with the article would be deleted along with every other instance of Augenstein's asinine article. The chances of my being able to convince any admin here or anywhere else to do something of that sort are between slim and none. I don't think that my persuasive powers are anywhere near that great. But I abhor the sort of nonsense that Augenstein wrote, and as long as it remains on the web, I will from time to time do this sort of thing. Just doing my own small part to fight nonsense, which, if I forgot to mention, I abhor.

I had no desire to "revive" the post. I would much have preferred to have posted the refutation of Augenstein, and that no one would have noticed, and that I would not now be finding myself in this. The purpose was expressly so that anyone who would chance upon the article, by way of a Google search or whatever, would have the benefit of an explanation of what is wrong with Augenstein's ridiculous, non-substantive explanation of torque and power. I would much, much prefer that what is happening now were not happening at all. I am not enjoying this in the least. To me, this is like having sharp pins stuck in my eyes. It is not the least bit fun. There is nothing remotely fun about it. This is the opposite of fun. But when you abhor nonsense even more than you abhor this kind of pain, you do what you have to do.

 

[boomdriver]

Stop listening to whoever told you that. There is no truth to that whatsoever. At any given instant, acceleration equates to actual power divided by the product of mass and velocity. That is a substantive fact. Neither torque nor power determines acceleration, at least not per the proper meaning of the word "determines". There are various different equations that you can write, that substantively relate torque to acceleration, and that substantively relate power to acceleration. In either case, there are other quantities, most notably mass, that enter into those equations. The simplest and most generally useful among such equations is the one that says that acceleration equates to power divided by the product of mass and velocity. As for top speed, acceleration gradually comes to zero as the total force of friction increases and becomes as great as vehicle thrust. Aerodynamic drag is the predominant friction, and it increases as the square of vehicle speed. When equilibrium is reached, thrust is in balance with total friction. Thrust equates to wheel torque divided by wheel radius. You can of course use the overall gear ratio to express wheel torque in terms of engine torque. But thrust also equates to power divided by vehicle speed, which means that when equilibrium is reached, power is in equilibrium with the product of vehicle speed and total friction.

And what exactly are YOUR credentials?

You come here, to school many people (uninvited) that have owned, worked on, built or tested Corvettes for many years (decades) and tell yourself that you know more about it that we do? Good for you. You keep telling yourself that you are smarter than everyone else around you and I'll keep sleeping well with what I know to be true.

You were much better off before you started bashing other folks for their opinions..and their experience.
I stand by my comments.
I suppose in your world, everyone else is crazy..

Again,

And what exactly are YOUR credentials? and which online class did you misunderstand Mr. Hawking?

 

[Nick Papagiorgio]

And what exactly are YOUR credentials?

You come here, to school many people (uninvited) that have owned, worked on, built or tested Corvettes for many years (decades) and tell yourself that you know more about it that we do? Good for you. You keep telling yourself that you are smarter than everyone else around you and I'll keep sleeping well with what I know to be true.

That is trash talk, plain and simple. I did not try to tell anyone anything at all about Corvettes. For you to suggest that I did that is ludicrous.

As I already explained, my reason for the post was simply to refute the nonsense that Augenstein wrote. You act as if this is all Corvette-specific, and that anyone who is here or who sees what is here will be a Corvette person with many years of experience with owning, building, etc. This is NOT a realistic interpretation of the situation here. Reality is that anyone who does a web search will easily find the article and this forum along with it, and will read Augenstein's specious article, and will be persuaded by its very presence here and by the accompanying comments that it is a correct article. I abhor that, and decided to do something about it. Given the real situation, my action was entirely justifiable. My intentions were perfectly honorable, and you are stretching reality to call my intentions into question when you do not have a single justification for doing that.

You were much better off before you started bashing other folks for their opinions..and their experience.
I stand by my comments.
I suppose in your world, everyone else is crazy..

I bash the stuff that other people say when they say stuff that amounts patently to nonsense. I rarely bash people per se, except when it is wholly called for. I have no qualms about bashing Augenstein, because he richly deserved it. He wrote that specious article even though he did not have any good reason to be confident in his understanding of the subject, and the understanding that he expounded was specious.

I did not bash anyone's experience. If you think that, that is just your way of looking at it. I did no such thing.

As for my thinking that everyone is crazy, that all depends on how you define "crazy". The sad fact is that when it comes to the very technical matters that are the true subject here, the majority of motoring enthusiasts say and believe things that amount to nonsense. That is a fact that I know with absolute certainty. If you define "crazy" as believing something that does not make sense, then according to that definition, then yes, most people are crazy. This isn't just my opinion. If the word "crazy" is defined that way, then it logically follows, from the fact that most people believe nonsense, that they are crazy. You wanted me to explain this to you, and I have no qualms about doing so, because I have told no lie in doing so.

And by the way, if you are the mature person that you represent yourself to be, how do you explain your use of that stupid little animated caricature? In a post that is entirely jovial in tone, those things are moderately humorous, but in a post that is of the character of your post, they are not the least bit appropriate, because they are overtly inflammatory, and do not add anything at all to the meaningful discussion, and are just plain juvenile.

Again,

And what exactly are YOUR credentials? and which online class did you misunderstand Mr. Hawking?

In the '70s I received a B.S. from a fully accredited state university in the southeastern part of the U.S.A. I majored in math and minored in physics, and I excelled in every math or physics course that I took. I studied subjects such as nuclear physics and electricity and magnetism. I have long since forgotten at least 95% of what I once knew, but for anyone who has ever actually studied physics, this torque and power stuff is so basic that it is never forgotten. It is not especially different from remembering how to do simple math.

And I have never once taken any on-line classes, and there is very little that I might have misunderstood back when I did study physics for a little while. In fact I probably understood it better than most other students did because I also took a philosophy of science course, which wasn't that great of a course, but it was not altogether a waste.

As for your sarcastic allusion to Mr. Hawking, I did not ever say anything to suggest that I would ever, ever compare myself to him, or think of myself in a similar light, or anything of that sort. Although I am certain that my appreciation of his remarkable achievement is much greater than is yours, because I have read several of his books and papers, and was able to grasp most all of it, whereas it is a fairly safe bet that you do not partake in that sort of thing.

Here's the bottom line: My post was entirely appropriate given that the article was there and that it was presented to anyone who knows how to do a simple web search. You took it upon yourself to write a ridiculous follow-up, and you probably did not even bother to read what I had written. If you did read it, you obviously did not understand it, in which case the mature response would have been to ask questions. I then responded to what you wrote in a manner that was entirely appropriate. I did not tell any lies. You then took insult, which was the inevitable outcome, and then you wrote something that amounts in totality to a personal insult. It very plainly is a personal insult, and yet within it, you accuse me of "bashing other folks". It was never my intent to bash anyone other than Augenstein. To the extent that I bashed you, you have no one but yourself to blame, because you wrote a bunch of stuff that made not one whit of sense, and you did it in response to a very specific and very correct refutation of a specious explanation of torque and power. You stepped in, of your own free will, and wrote a bunch of more nonsense, claiming that you were going to "define" torque and power in simple terms so that there "is no need for any confusion", and then you wrote something that did not make a whit of sense. That is exactly what you did. In saying this plainly, I am not telling any lie.

I have the urge to say this: when it comes to explanations of torque and power, anyone who would approach it by saying anything along the lines of "torque does this, whereas power does this", should be ignored outright. This general approach, i.e., the notion that there are certain effects or consequences of torque, and that there are other effects or consequences of power, and that these effects are separate from each other and that torque and power should be understood on this basis, is as preposterous as any idea that I have every encountered. Yet, I encounter this sort of thing very often. For some reason, when naive people take it upon themselves to "explain" torque and power, this is quite often what they do. "Torque is what does this, and power is what does this". Not in those exact words of course, but you probably get the idea. This approach is ludicrous. Explanations of torque and power that are substantive and correct always, always, always focus on the precise, substantive manner in which acceleration at a given instant in time is analytically related to actual power at that instant and to actual torque at that instant. Substantive explanations always, always adhere to this because this is where the substantive understanding inherently is rooted.

Now, boomdriver, this is the last response that you will see from me, to anything that you write that remotely resembles a personal attack on me. You are free and welcome to bash me to your heart's content, and I will ignore it outright.

But if you have any questions on the technical subject and would like to discuss them, I am happy to engage in a conversation on that. As long as you do not make it personal. And if you want to engage in a technical discussion on torque and power, I implore you to steer clear of statements and assertions. A lifetime of experience working on Corvettes does not endow you with expert knowledge on torque and power. The plain truth is that very few people who have never studied physics formally even have the first clue how to go about approaching the subject in a substantive manner. In saying this, I have told no lie.

 

[boomdriver]

......uh-huh.:eyerole