Gas vs PSD
Postmaster
Joined: Oct 2006
Posts: 4,171
Likes: 12
From: SE Texas
Sorry, Torque is the Power/work and is what is Measured when you put your truck on a Dyno. Horsepower is how fast that work is accomplished.
What is Horsepower?
What is Horsepower?
Don't believe me?
Do a dyno pull with no RPM input and see what gets printed on the sheet and what's missing.
JL
Posting Guru
Joined: Aug 2007
Posts: 1,317
Likes: 0
From: Auburn, Wa
Sorry-you're wrong. Dynos measure the amount of work over time. The unit of work is Horsepower. Torque is calculated post dyno pull by the dyno software.
Don't believe me?
Do a dyno pull with no RPM input and see what gets printed on the sheet and what's missing.
JL
Don't believe me?
Do a dyno pull with no RPM input and see what gets printed on the sheet and what's missing.
JL
wiki- Dynamometer - Wikipedia, the free encyclopedia
A dynamometer or "dyno" for short, is a device for measuring force, moment of force (torque), or power. For example, the power produced by an engine, motor or other rotating prime mover can be calculated by simultaneously measuring torque and rotational speed (rpm).
also
How Does a Dyno Work? | eHow.com
Lead Driver
Joined: Jul 2007
Posts: 7,868
Likes: 9
From: Rhode Island
Sorry, Torque is the Power/work and is what is Measured when you put your truck on a Dyno. Horsepower is how fast that work is accomplished.
What is Horsepower?
What is Horsepower?
No modern dyno measures torque either. All modern dynos measure power and then derive torque through calculations. The three most common dynos are:
1. Inertia Dyno. accelerating a heavy drum, where a computer measures how fast the drum was accelerated(the power that was put to the drum) and based on an RPM trigger sensor placed somewhere on the engine, the dyno's computer can figure out how much torque the engine put out.
2. Electrical dyno. The wheels (or engine crankshaft) essentially spin an electrical generator which is connected to an electronic load bank. It measures exactly how much power is generated, and once again using a crank sensor it calculates the torque by how much power was generated at a specific RPM.
3. Hydraulic dyno. An engine is loaded up into a hydraulic motor, either pumping hydraulic fluid or water, and some kind of restriction is put in line with the output. A computer measures how much fluid the engine can force through the orifice at a given pressure and then calculates the power being produced. Want to take a guess on how it calculates torque? You guessed it, a sensor measures the RPM and it calculates the torque from the power.
The only type of dyno that I'm aware of that measures torque (and NOT power) is the de Prony brake, and whens the last time you you hooked your truck upto one of those?
You need to read up and understand a little morezon how and why a diesel actually works because you seem to have half the info and the rest got lost somewhere. your also passing along mis-information.
Here is some basics on how they work. Pay close attention to the part how they actually com-bust the fuel they inject.
HowStuffWorks "How Diesel Engines Work"
Here is some basics on how they work. Pay close attention to the part how they actually com-bust the fuel they inject.
HowStuffWorks "How Diesel Engines Work"
Postmaster
Joined: Oct 2006
Posts: 4,171
Likes: 12
From: SE Texas
the thing about it is... said engine makes power/torque to move an object. in this case the Dyno, Yes i have been on a dyno But torque is what builds and leads to Horsepower because Horsepower is work over time. There is also a variables as to what dyno is being used. Owning a diesel truck its hard finding a dyno that can load our engines right and also a dyno operator that can set it up for a diesel. Because when we get on a dyno that isn't we get stupid high false numbers. the fact is Horsepower is a result of Torque because it is merely a measurement of how fast that work is done. Basically its gets pretty in depth, I cannot explain any further however is ErnestEugene is around I'm sure he can get into the Leading particulars of the subject.
wiki- Dynamometer - Wikipedia, the free encyclopedia
A dynamometer or "dyno" for short, is a device for measuring force, moment of force (torque), or power. For example, the power produced by an engine, motor or other rotating prime mover can be calculated by simultaneously measuring torque and rotational speed (rpm).
also
How Does a Dyno Work? | eHow.com
wiki- Dynamometer - Wikipedia, the free encyclopedia
A dynamometer or "dyno" for short, is a device for measuring force, moment of force (torque), or power. For example, the power produced by an engine, motor or other rotating prime mover can be calculated by simultaneously measuring torque and rotational speed (rpm).
also
How Does a Dyno Work? | eHow.com
Dynos measure horsepower-period.
JL
Lead Driver
Joined: Jul 2007
Posts: 7,868
Likes: 9
From: Rhode Island
Just to add, the only dyno that possibly may not be able to load up a Diesel is an inertia type dyno, because of turbo lag. The drum may have already be spun most of the way up before the turbo lights off.
But besides that Johnny Langton is correct, a dyno should not care whether or not its a diesel or a gas engine. Any settings that a dyno operator is changing are just trying to give people an estimation on horsepower being produced at the crank.
But besides that Johnny Langton is correct, a dyno should not care whether or not its a diesel or a gas engine. Any settings that a dyno operator is changing are just trying to give people an estimation on horsepower being produced at the crank.
Posting Guru
Joined: Aug 2007
Posts: 1,317
Likes: 0
From: Auburn, Wa
Do big rigs accelerate fast? Nope. Do they have high top speeds? Nope. Can they pull hills fast? Nope. That is all because of a lack of horsepower.
The reason big rig engines have such high torque, is because the engines spin so slow. Topping out at ~2000 RPM. The slow spinning engine is a necessity for long hauling. It helps conserve fuel, and it means the engine will last longer since its spinning so slow.
Here this diesel spins at 102 RPMS, However its the most powerful one in the world. The Most Powerful Diesel Engine in the World
HowStuffWorks "Why do big diesel engines and race car engines have such differe"
"Let's start by answering the question and then look at why the world works that way. The answer to your question has to do with the way the two engines are designed. Your 11 liter diesel engine has a long stroke. That means that the piston is traveling a relatively long distance up and down in its cylinder on each cycle. A racing engine, on the other hand, has a short stroke. The piston in a racing engine has a large diameter for the engine size, and it goes up and down a relatively short distance on each cycle. This means that a race car engine can run much faster -- up to 15,000 RPM in a Champ Car engine -- but has relatively little torque. A large diesel engine usually cannot get above 2,000 RPM, but has huge torque because of the long stroke. The torque is what lets your engine pull a huge load up a hill."
Once again torque moves stuff not Horsepower.
If you put that 362HP V10 into that same big rig that had that 330HP 1400 lb-ft diesel, and gearing in it so that the engine spins ~4500 RPM in the highest gear at 65-70MPH; it will out pull that giant diesel. Will the V10 last long spinning 4500 RPM at WOT day and day out? Probably not, but it will still output that lower HP diesel. In fact, if you had a little 350HP Turbo V6 or 4 Cylinder and geared it so it spun 6000-7000 RPM at 65MPH in top gear, it would output that big diesel too.
The reason big rig engines have such high torque, is because the engines spin so slow. Topping out at ~2000 RPM. The slow spinning engine is a necessity for long hauling. It helps conserve fuel, and it means the engine will last longer since its spinning so slow.
Here this diesel spins at 102 RPMS, However its the most powerful one in the world. The Most Powerful Diesel Engine in the World
HowStuffWorks "Why do big diesel engines and race car engines have such differe"
"Let's start by answering the question and then look at why the world works that way. The answer to your question has to do with the way the two engines are designed. Your 11 liter diesel engine has a long stroke. That means that the piston is traveling a relatively long distance up and down in its cylinder on each cycle. A racing engine, on the other hand, has a short stroke. The piston in a racing engine has a large diameter for the engine size, and it goes up and down a relatively short distance on each cycle. This means that a race car engine can run much faster -- up to 15,000 RPM in a Champ Car engine -- but has relatively little torque. A large diesel engine usually cannot get above 2,000 RPM, but has huge torque because of the long stroke. The torque is what lets your engine pull a huge load up a hill."
Once again torque moves stuff not Horsepower.
If you put that 362HP V10 into that same big rig that had that 330HP 1400 lb-ft diesel, and gearing in it so that the engine spins ~4500 RPM in the highest gear at 65-70MPH; it will out pull that giant diesel. Will the V10 last long spinning 4500 RPM at WOT day and day out? Probably not, but it will still output that lower HP diesel. In fact, if you had a little 350HP Turbo V6 or 4 Cylinder and geared it so it spun 6000-7000 RPM at 65MPH in top gear, it would output that big diesel too.
A dyno does not care whether it's a gasoline powered vehicle, a diesel powered vehicle, or a kid on a bicycle. Open torque converters and slipping clutches are what give falsely high dyno numbers. Anybody that's "setting up" a dyno or changing operating parameters of a dyno just because it's a diesel on the rollers is "cooking the books" to make the numbers and/or the shop/tuner look good.
Dynos measure horsepower-period.
JL
Dynos measure horsepower-period.
JL
Just to add, the only dyno that possibly may not be able to load up a Diesel is an inertia type dyno, because of turbo lag. The drum may have already be spun most of the way up before the turbo lights off.
But besides that Johnny Langton is correct, a dyno should not care whether or not its a diesel or a gas engine. Any settings that a dyno operator is changing are just trying to give people an estimation on horsepower being produced at the crank.
But besides that Johnny Langton is correct, a dyno should not care whether or not its a diesel or a gas engine. Any settings that a dyno operator is changing are just trying to give people an estimation on horsepower being produced at the crank.
if i'm wrong about the dyno then so be it. But considering Engines all of them Make Torque and then Horsepower is based on how fast that torque is being done. I will still go with Dynos measure Torque and the rate at which that work is done is how they get that Horsepower. Read the article I posted above, If you still refuse to believe how engines make Torque and that Horsepower is only how fast the work is done not how much work it can do. Then so be it.
Postmaster
Joined: Apr 2008
Posts: 4,724
Likes: 4
From: Rogersville, TN
Sorry it took me a while to get back to you. I had a funeral to go to today and I just got home. While our diesels are doing their work they are set to high idle, but there are times they sit on location idling for 8-10 hours waiting on their job to start. The company that used v10's were very rarely left idling. They would bring some sort of supplies in, drop them off, and then head to the next job site. It's a lot of two lane, hilly, curvy type roads and the drivers just run the dog crap out of them. Then throw in the fact that most of our lease roads leading to the job site are in the ~50% and above grade range. One of our lease roads goes from 2k feet to 2800 feet in less than 1,000 feet. We have a few roads that are so steep that you have to be pulled in by a dozer even when it's a dry. Hauling a big load up a hill like that several times a day, 7 days a week can really put a strain on an engine.
Freshman User
Joined: Mar 2010
Posts: 48
Likes: 0
From: Tucson, AZ
I may be new to the forum, but I am far from new to dynos, here is a decent explanation:
Horsepower Definition: How much work is done over what period of time.
Many years before Mercedes Benz was producing engines with over 450 horsepower, a man named James Watt made some observations, and concluded that an average horse 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. Watt published those observations, and stated that 33,000 foot pounds per minute of work was equivalent to the power of one horse, or, to cite on of our topic of the day, one horsepower.
To further explain, let us look at the following scenario. 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 (hence, you have zero horsepower.) 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.
•••
Torque Definition: The measure of the force applied to an object to produce rotational motion, usually measured in foot-pounds.
Torque literally refers to the turning or twisting force of an engine An engine may be very powerful, but if it has little torque then that power may only be available over a very high and limited rev range, making it of limited use to the driver. An engine with more torque - even if it has less power – often proves to be much quicker on the track, as the power is available over a far wider rev range and hence more accessible.
To give a slightly more technical explanation, one 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.
Imagine, if you will, this one pound weight, 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, incidentally, we have done 6.2832 foot pounds of work.
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 dynamometer) 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.
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:
Horsepower =
Torque*RPM
5252
Many years before Mercedes Benz was producing engines with over 450 horsepower, a man named James Watt made some observations, and concluded that an average horse 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. Watt published those observations, and stated that 33,000 foot pounds per minute of work was equivalent to the power of one horse, or, to cite on of our topic of the day, one horsepower.
To further explain, let us look at the following scenario. 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 (hence, you have zero horsepower.) 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.
•••
Torque Definition: The measure of the force applied to an object to produce rotational motion, usually measured in foot-pounds.
Torque literally refers to the turning or twisting force of an engine An engine may be very powerful, but if it has little torque then that power may only be available over a very high and limited rev range, making it of limited use to the driver. An engine with more torque - even if it has less power – often proves to be much quicker on the track, as the power is available over a far wider rev range and hence more accessible.
To give a slightly more technical explanation, one 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.
Imagine, if you will, this one pound weight, 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, incidentally, we have done 6.2832 foot pounds of work.
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 dynamometer) 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.
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:
Horsepower =
Torque*RPM
5252
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Posting Guru
Joined: Aug 2007
Posts: 1,317
Likes: 0
From: Auburn, Wa
so an Engine produces Torque/work and if Horsepower is a measurement of how fast that work is being accomplished.
Ergo,
An Dyno measures torque of a vehicle and calculates Horsepower based on the speed of the engine.
Lead Driver
Joined: Jul 2007
Posts: 7,868
Likes: 9
From: Rhode Island
Here this diesel spins at 102 RPMS, However its the most powerful one in the world. The Most Powerful Diesel Engine in the World
HowStuffWorks "Why do big diesel engines and race car engines have such differe"
"Let's start by answering the question and then look at why the world works that way.
"Let's start by answering the question and then look at why the world works that way.
The answer to your question has to do with the way the two engines are designed. Your 11 liter diesel engine has a long stroke. That means that the piston is traveling a relatively long distance up and down in its cylinder on each cycle. A racing engine, on the other hand, has a short stroke. The piston in a racing engine has a large diameter for the engine size, and it goes up and down a relatively short distance on each cycle. This means that a race car engine can run much faster -- up to 15,000 RPM in a Champ Car engine -- but has relatively little torque. A large diesel engine usually cannot get above 2,000 RPM, but has huge torque because of the long stroke. The torque is what lets your engine pull a huge load up a hill."
Once again torque moves stuff not Horsepower.
Once again torque moves stuff not Horsepower.
Once again, you're wrong. I can apply torque to something, but it needs to be rotating torque to actually move something. The moment I start to rotate that force, it becomes power. Power is what lets those big diesels pull a huge load. They have lots of low end torque, so they can still generate useable power at low RPMs. Once again, spinning at low RPMs maximizes engine life and fuel economy. More power down low also makes it more pleasant to tow as you may not have to downshift as much, But ultimately its the power the engine is putting out that is moving that load.
<!-- END TEMPLATE: bbcode_quote -->
That would require some stupid low gears to get enough mechanical advantage to do the same work.
And once again, most dynos measure power, not torque. Here is a picture from wikipedia that shows it well:
This is an electrical dyno. It generates electricity which gets measured in watts (watts is power, 746 Watts = 1HP) This shows how much HP the engine generates. This type of dyno cannot measure torque directly. So, it needs that torque arm + scale (4,5 on the picture). The generator housing is free to rotate on the trunnions, the torque arm is attached to the housing and the other end of the scale is attached to something solid. As the dyno operator loads up the engine with the generator, the scale measures how much the generator housing twists/pulls against it. This is the engine's torque reading. So it needs this scale/arm to measure torque. You could figure the torque based on engine RPMs and how much power its generating, but it won't be as accurate.
Elder User
Joined: May 2007
Posts: 699
Likes: 1
6lb, you can make the boost any time you want with the kenne bell kit, if you put it to the floor at 1750 rpm and it will make that 6 lb until you let off, there is no lag or gradual build of boost through the rpm range, but with a vacume gauge you can vary the amount of boost you are or aren't making.
Senior User
Joined: Oct 2009
Posts: 281
Likes: 0
From: West TN
So a v 10 that has 6.8 liters will out pull my 12.7 liter inline 6 diesel if it is geared right? The way i see it is. It doesnt really matter what is said or proved you can never convince some people that diesels are designed for pulling more than gassers. I have stopped at truck stops all across the south and have yet to find one with gas pumps for big rigs. Even if you could gear the truck right you would melt the pistons running it all day at 4k to 5k rpms. I will still own diesel trucks no matter what. Paying the extra money doesnt bother me for the piece of mind the diesel gives me.
Lead Driver
Joined: Jul 2007
Posts: 7,868
Likes: 9
From: Rhode Island
So a v 10 that has 6.8 liters will out pull my 12.7 liter inline 6 diesel if it is geared right? The way i see it is. It doesnt really matter what is said or proved you can never convince some people that diesels are designed for pulling more than gassers. I have stopped at truck stops all across the south and have yet to find one with gas pumps for big rigs. Even if you could gear the truck right you would melt the pistons running it all day at 4k to 5k rpms. I will still own diesel trucks no matter what. Paying the extra money doesnt bother me for the piece of mind the diesel gives me.
Freshman User
Joined: Mar 2010
Posts: 48
Likes: 0
From: Tucson, AZ
Whats your point? The engine is still spinning, and therefore is making power.
Once again, you're wrong. I can apply torque to something, but it needs to be rotating torque to actually move something. The moment I start to rotate that force, it becomes power. Power is what lets those big diesels pull a huge load. They have lots of low end torque, so they can still generate useable power at low RPMs. Once again, spinning at low RPMs maximizes engine life and fuel economy. More power down low also makes it more pleasant to tow as you may not have to downshift as much, But ultimately its the power the engine is putting out that is moving that load.
<!-- END TEMPLATE: bbcode_quote -->Yes, I know that. But with that stupidly low gearing, it would have more pulling ability with the same top speed as that Diesel. That proves that when it comes down to it, power is what moves loads.
And once again, most dynos measure power, not torque. Here is a picture from wikipedia that shows it well:
This is an electrical dyno. It generates electricity which gets measured in watts (watts is power, 746 Watts = 1HP) This shows how much HP the engine generates. This type of dyno cannot measure torque directly. So, it needs that torque arm + scale (4,5 on the picture). The generator housing is free to rotate on the trunnions, the torque arm is attached to the housing and the other end of the scale is attached to something solid. As the dyno operator loads up the engine with the generator, the scale measures how much the generator housing twists/pulls against it. This is the engine's torque reading. So it needs this scale/arm to measure torque. You could figure the torque based on engine RPMs and how much power its generating, but it won't be as accurate.
Once again, you're wrong. I can apply torque to something, but it needs to be rotating torque to actually move something. The moment I start to rotate that force, it becomes power. Power is what lets those big diesels pull a huge load. They have lots of low end torque, so they can still generate useable power at low RPMs. Once again, spinning at low RPMs maximizes engine life and fuel economy. More power down low also makes it more pleasant to tow as you may not have to downshift as much, But ultimately its the power the engine is putting out that is moving that load.
<!-- END TEMPLATE: bbcode_quote -->Yes, I know that. But with that stupidly low gearing, it would have more pulling ability with the same top speed as that Diesel. That proves that when it comes down to it, power is what moves loads.
And once again, most dynos measure power, not torque. Here is a picture from wikipedia that shows it well:
This is an electrical dyno. It generates electricity which gets measured in watts (watts is power, 746 Watts = 1HP) This shows how much HP the engine generates. This type of dyno cannot measure torque directly. So, it needs that torque arm + scale (4,5 on the picture). The generator housing is free to rotate on the trunnions, the torque arm is attached to the housing and the other end of the scale is attached to something solid. As the dyno operator loads up the engine with the generator, the scale measures how much the generator housing twists/pulls against it. This is the engine's torque reading. So it needs this scale/arm to measure torque. You could figure the torque based on engine RPMs and how much power its generating, but it won't be as accurate.
On modern day dynamometers horsepower is a calculated value. It's important to remember the dyno measures torque and rpm and then from these calculates horsepower. On the dyno it takes more water flow to the water brake to increase the load on the engine being tested. As the test engine's torque rises more water flow is needed. As the test engine's torque drops less water flow is needed. The dyno's water brake does not respond to Horsepower. Major adjustments to water flow are needed as an engine crosses its torque peak but none are needed as it crosses its horsepower peak. In other words the water flow to the brake during a dyno test follows the engines torque curve and not its horsepower curve. Torque is what twists the tire, prop, or pump. Horsepower helps us understand an amount or quantity of torque. (Torque + time and distance)