Torque and HP - Revision history

Nyet: Reverted edits by ClaelRolae (Talk); changed back to last version by Nyet

2008-12-27T19:28:31Z

Reverted edits by ClaelRolae (Talk); changed back to last version by Nyet

← Older revision		Revision as of 19:28, 27 December 2008
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	nolivarla
	== Torque and Horsepower - A Primer ==		== Torque and Horsepower - A Primer ==

ClaelRolae: letotar

2008-12-16T23:23:47Z

letotar

← Older revision		Revision as of 23:23, 16 December 2008
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			nolivarla
	== Torque and Horsepower - A Primer ==		== Torque and Horsepower - A Primer ==

Nyet at 00:20, 2 September 2006

2006-09-02T00:20:09Z

← Older revision		Revision as of 00:20, 2 September 2006
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	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:		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
	Torque * RPM
	Horsepower = ------------		Horsepower = ------------
			5252
	5252



	This is not a debatable item. It's the way it's done. Period.		This is not a debatable item. It's the way it's done. Period.
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	A very good example would be to compare the current LT1 Corvette with the last of the L98 Vettes, built in 1991. Figures as follows:		A very good example would be to compare the current LT1 Corvette with the last of the L98 Vettes, built in 1991. Figures as follows:

	Engine Peak HP @ RPM Peak Torque @ RPM		Engine Peak HP @ RPM Peak Torque @ RPM
	------ ------------- -----------------		------ ------------- -----------------
	L98 250 @ 4000 340 @ 3200		L98 250 @ 4000 340 @ 3200
	LT1 300 @ 5000 340 @ 3600<font color="#af0000">		LT1 300 @ 5000 340 @ 3600<font color="#af0000">
	</font>		</font>

	<font color="#008000">[Numbers for 94 Integra LS/RS and GS-R</font>		<font color="#008000">[Numbers for 94 Integra LS/RS and GS-R</font>

	<font color="#008000">		<font color="#008000">
	Engine Peak HP @ RPM Peak Torque @ RPM		Engine Peak HP @ RPM Peak Torque @ RPM
	------ ------------- -----------------		------ ------------- -----------------
	B18B 142 @ 6300 127 @ 5200		B18B 142 @ 6300 127 @ 5200
	B18C 170 @ 7600 128 @ 6200		B18C 170 @ 7600 128 @ 6200
	</font>		</font>

	<font color="#008000">If you overlap the torque curve for B18B and B18C, you'll see that B18C's maximum torque (127 vs. 128 ft-lbs) is about the same as B18B, except B18C's torque curve just keeps on climbing, thus the much higher HP. B18B and B18C are quite similar, but not identical. Mostly notably the B18B has slightly longer stroke, which gives it the displacement of 1835 cc vs. B18C's 1797 cc. The stroke explains why the B18B has better low end, and it is also a factor why it revs slower and has lower redline than B18C. Monitor YAHP for an article that will talk about the basic relationship between bore and stroke. - Frank]</font>		<font color="#008000">If you overlap the torque curve for B18B and B18C, you'll see that B18C's maximum torque (127 vs. 128 ft-lbs) is about the same as B18B, except B18C's torque curve just keeps on climbing, thus the much higher HP. B18B and B18C are quite similar, but not identical. Mostly notably the B18B has slightly longer stroke, which gives it the displacement of 1835 cc vs. B18C's 1797 cc. The stroke explains why the B18B has better low end, and it is also a factor why it revs slower and has lower redline than B18C. Monitor YAHP for an article that will talk about the basic relationship between bore and stroke. - Frank]</font>




	The cars are geared identically, and car weights are within a few pounds, so it's a good comparison.		The cars are geared identically, and car weights are within a few pounds, so it's a good comparison.
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	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:		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		Horsepower * 5252
	Torque = -----------------		Torque = -----------------
			RPM
	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.		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.
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			[[Category:FAQs]]

Pansgor at 21:10, 26 July 2006

2006-07-26T21:10:38Z

← Older revision		Revision as of 21:10, 26 July 2006
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Pansgor at 21:09, 26 July 2006

2006-07-26T21:09:24Z

← Older revision		Revision as of 21:09, 26 July 2006
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	----		----

	<font color="#~~00800~~">[Before I let Bruce explains the stuff, here's a quick summary. Remember that the magic number 5252 works only with torque in ft-lbs units. Torque in other units such as Newton Meters or kg-m require a different number.</font>		<font color="#008000">[Before I let Bruce explains the stuff, here's a quick summary. Remember that the magic number 5252 works only with torque in ft-lbs units. Torque in other units such as Newton Meters or kg-m require a different number.</font>

	<font color="#~~00800~~">- Maximum acceleration at any speed occurs at the HP peak.<br />- Maximum acceleration in any gear occurs at the torque peak<br />- HP = torque * RPM / 5252<br />- torque = HP * 5252 / RPM<br />- torque = HP at 5252 RPM</font>		<font color="#008000">- Maximum acceleration at any speed occurs at the HP peak.<br />- Maximum acceleration in any gear occurs at the torque peak<br />- HP = torque * RPM / 5252<br />- torque = HP * 5252 / RPM<br />- torque = HP at 5252 RPM</font>

	<font color="#~~00800~~">HP is not measured directly, it is simply calculated from torque. However the HP to torque formula is useful to figure out how much torque the engine is making at peak HP. I wish when the car magazines do a road test they would include the torque and HP graph, gear ratios vs speed, 0 to top speed table in every 10 miles with G (acceleration) values... etc. - Frank]</font>		<font color="#008000">HP is not measured directly, it is simply calculated from torque. However the HP to torque formula is useful to figure out how much torque the engine is making at peak HP. I wish when the car magazines do a road test they would include the torque and HP graph, gear ratios vs speed, 0 to top speed table in every 10 miles with G (acceleration) values... etc. - Frank]</font>

	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 :-). I've posted a subset of this note in another string, but felt it deserved to be dealt with as a separate topic. This is meant to be a primer on the subject, which may lead to serious discussion that fleshes out this and other sub-topics that will inevitably need to be addressed.		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 :-). I've posted a subset of this note in another string, but felt it deserved to be dealt with as a separate topic. This is meant to be a primer on the subject, which may lead to serious discussion that fleshes out this and other sub-topics that will inevitably need to be addressed.

	<font color="#~~00800~~">[Bruce hit it dead on. Anyone who's read UseNet for a period of time knows how much crap is on it. There are many knowledgeable folks posting quality discussions (in all newsgroups) but they are easily overshadowed by stupid posts. - Frank]</font>		<font color="#008000">[Bruce hit it dead on. Anyone who's read UseNet for a period of time knows how much crap is on it. There are many knowledgeable folks posting quality discussions (in all newsgroups) but they are easily overshadowed by stupid posts. - Frank]</font>

	OK. Here's the deal, in moderately plain english.		OK. Here's the deal, in moderately plain english.
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	</font>		</font>

	<font color="#~~00800~~">[Numbers for 94 Integra LS/RS and GS-R</font>		<font color="#008000">[Numbers for 94 Integra LS/RS and GS-R</font>

	<font color="#~~00800~~">		<font color="#008000">
	Engine Peak HP @ RPM Peak Torque @ RPM		Engine Peak HP @ RPM Peak Torque @ RPM
	------ ------------- -----------------		------ ------------- -----------------
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	</font>		</font>

	<font color="#~~00800~~">If you overlap the torque curve for B18B and B18C, you'll see that B18C's maximum torque (127 vs. 128 ft-lbs) is about the same as B18B, except B18C's torque curve just keeps on climbing, thus the much higher HP. B18B and B18C are quite similar, but not identical. Mostly notably the B18B has slightly longer stroke, which gives it the displacement of 1835 cc vs. B18C's 1797 cc. The stroke explains why the B18B has better low end, and it is also a factor why it revs slower and has lower redline than B18C. Monitor YAHP for an article that will talk about the basic relationship between bore and stroke. - Frank]</font>		<font color="#008000">If you overlap the torque curve for B18B and B18C, you'll see that B18C's maximum torque (127 vs. 128 ft-lbs) is about the same as B18B, except B18C's torque curve just keeps on climbing, thus the much higher HP. B18B and B18C are quite similar, but not identical. Mostly notably the B18B has slightly longer stroke, which gives it the displacement of 1835 cc vs. B18C's 1797 cc. The stroke explains why the B18B has better low end, and it is also a factor why it revs slower and has lower redline than B18C. Monitor YAHP for an article that will talk about the basic relationship between bore and stroke. - Frank]</font>

Pansgor at 21:08, 26 July 2006

2006-07-26T21:08:38Z

← Older revision		Revision as of 21:08, 26 July 2006
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	----		----

	<font color="#~~80ff80~~">[Before I let Bruce explains the stuff, here's a quick summary. Remember that the magic number 5252 works only with torque in ft-lbs units. Torque in other units such as Newton Meters or kg-m require a different number.</font>		<font color="#00800">[Before I let Bruce explains the stuff, here's a quick summary. Remember that the magic number 5252 works only with torque in ft-lbs units. Torque in other units such as Newton Meters or kg-m require a different number.</font>

	<font color="#~~80ff80~~">- Maximum acceleration at any speed occurs at the HP peak.<br />- Maximum acceleration in any gear occurs at the torque peak<br />- HP = torque * RPM / 5252<br />- torque = HP * 5252 / RPM<br />- torque = HP at 5252 RPM</font>		<font color="#00800">- Maximum acceleration at any speed occurs at the HP peak.<br />- Maximum acceleration in any gear occurs at the torque peak<br />- HP = torque * RPM / 5252<br />- torque = HP * 5252 / RPM<br />- torque = HP at 5252 RPM</font>

	<font color="#~~80ff80~~">HP is not measured directly, it is simply calculated from torque. However the HP to torque formula is useful to figure out how much torque the engine is making at peak HP. I wish when the car magazines do a road test they would include the torque and HP graph, gear ratios vs speed, 0 to top speed table in every 10 miles with G (acceleration) values... etc. - Frank]</font>		<font color="#00800">HP is not measured directly, it is simply calculated from torque. However the HP to torque formula is useful to figure out how much torque the engine is making at peak HP. I wish when the car magazines do a road test they would include the torque and HP graph, gear ratios vs speed, 0 to top speed table in every 10 miles with G (acceleration) values... etc. - Frank]</font>

	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 :-). I've posted a subset of this note in another string, but felt it deserved to be dealt with as a separate topic. This is meant to be a primer on the subject, which may lead to serious discussion that fleshes out this and other sub-topics that will inevitably need to be addressed.		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 :-). I've posted a subset of this note in another string, but felt it deserved to be dealt with as a separate topic. This is meant to be a primer on the subject, which may lead to serious discussion that fleshes out this and other sub-topics that will inevitably need to be addressed.

	<font color="#~~80ff80~~">[Bruce hit it dead on. Anyone who's read UseNet for a period of time knows how much crap is on it. There are many knowledgeable folks posting quality discussions (in all newsgroups) but they are easily overshadowed by stupid posts. - Frank]</font>		<font color="#00800">[Bruce hit it dead on. Anyone who's read UseNet for a period of time knows how much crap is on it. There are many knowledgeable folks posting quality discussions (in all newsgroups) but they are easily overshadowed by stupid posts. - Frank]</font>

	OK. Here's the deal, in moderately plain english.		OK. Here's the deal, in moderately plain english.
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	</font>		</font>

	<font color="#~~80ff80~~">[Numbers for 94 Integra LS/RS and GS-R</font>		<font color="#00800">[Numbers for 94 Integra LS/RS and GS-R</font>

	<font color="#~~80ff80~~">		<font color="#00800">
	Engine Peak HP @ RPM Peak Torque @ RPM		Engine Peak HP @ RPM Peak Torque @ RPM
	------ ------------- -----------------		------ ------------- -----------------
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	</font>		</font>

	<font color="#~~80ff80~~">If you overlap the torque curve for B18B and B18C, you'll see that B18C's maximum torque (127 vs. 128 ft-lbs) is about the same as B18B, except B18C's torque curve just keeps on climbing, thus the much higher HP. B18B and B18C are quite similar, but not identical. Mostly notably the B18B has slightly longer stroke, which gives it the displacement of 1835 cc vs. B18C's 1797 cc. The stroke explains why the B18B has better low end, and it is also a factor why it revs slower and has lower redline than B18C. Monitor YAHP for an article that will talk about the basic relationship between bore and stroke. - Frank]</font>		<font color="#00800">If you overlap the torque curve for B18B and B18C, you'll see that B18C's maximum torque (127 vs. 128 ft-lbs) is about the same as B18B, except B18C's torque curve just keeps on climbing, thus the much higher HP. B18B and B18C are quite similar, but not identical. Mostly notably the B18B has slightly longer stroke, which gives it the displacement of 1835 cc vs. B18C's 1797 cc. The stroke explains why the B18B has better low end, and it is also a factor why it revs slower and has lower redline than B18C. Monitor YAHP for an article that will talk about the basic relationship between bore and stroke. - Frank]</font>


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Pansgor at 21:07, 26 July 2006

2006-07-26T21:07:42Z

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Nyet at 21:07, 26 July 2006

2006-07-26T21:07:34Z

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