I use
TXD: 07E02209CB
RXF: 0462050906CB
RXD: 3010
MTH: 000100010000

No tune or mod on the truck and the reading is more than 650 ft lbs at near or full thottle. The spec. for this truck is only 560 ft lbs, is this value at the wheel? and the value from scanguage II is from the fly wheel?

Thanks,

 

Only a guess but it is probably calculating torque from fuel usage. I don't think there is an actual torque sensor. One of the stock gauges is horsepower - horsepower and torque are the same thing, except for RPM and a constant multiplier. I would love to know for sure, though.

torque times RPM divided by 5252 equals horsepower. That is why I ignore torque statistics. Horsepower is what does work, so I look for HP in the RPM range I want to run at. Of course, a big torque number at a low RPM equals great performance on the road towing, that's for sure.

Brian

 

Where did you get this formula: 5252/rpm = Hp

 

torque is what gets you moving. HP is what keeps you moving.

this is why diesels are better than gassers for towing.
diesels make big torque numbers at low RPM an thats why they tow better than gassers

 

Torque times RPM/5252 is the formula for horsepower. The 5252 is just a constant, it comes from the original definition of horsepower back when it was actually a horse... All dyno's measure torque with a load cell attached to the engine brake. Basically you spin the brake with the engine and apply enough force to balance the engine power, then you read the load cell to tell how hard the brake is being twisted. You then apply that formula to calculate the horsepower.

The reason I don't worry about torque is it can't actually do anything because it's a static measurement. You can easily get 1000 ft lbs of torque by hanging a 100 lb weight at the end of a 10 foot long stick, but it can't do anything for you. Horsepower can actually do work, since it is power applied over time. So I focus on the horsepower curve to see where the engine is making power, and how much it makes. An electric motor makes it's maximum torque at 0 RPM, so it's doing no work at all for you. My bus engine makes around 1100 ft lbs of torque at 1200 RPM, but it can't pull the skin off a pudding there, it's making no horsepower. At 2300 rpm it's making 400 hp.

I did a comparo between the 6.0 PSD and my 5.7 Hemi gasser. At 2000 rpm, right where I want to be towing up a hill, it makes over double the horsepower than the Hemi. That's why it works so hard on the road. The Hemi can out-drag it at the lights all day long, because it makes 50 more HP at peak, and I can run it at 5500 rpm when accelerating away from a light. But it's always HP doing the work.

Brian

 

I will take this opportunity to correct you ... Chris and I generally agree on the concepts, and other than some semantics, are pretty much aligned, so I suspect he'd disagree with you as well.
It is improper to discount torque in any conversation about moving things with vehicles. Torque is fundamental in every aspect. As is time. Because torque and time are the components of power when it comes to engines. You must know the value of both to understand the conversation of "horsepower".

Remember these things:
Force = mass x acceleration
Work = Force x displacement
Torque = Force x distance
Power = work / time

Torque can be both static and dynamic. Simple electric motors (such as shaded pole and PSC) make their torque from 0 rpm to their max rpm (typically either 1800 or 3600 rpm).

Work, properly defined, is the concept of a force applied over a displacement. And that's where many folks get off track. In fact, that is where Chris and I probably had our disagreement at first, but I now believe we would agree on what I am now more accurately defining. There is a difference between "distance" and "displacement". (I'm not talking about the volumetric measurement of "displacement" of an internal combustion engine). I am talking about linear displacement. Displacement is moving something from one location to another. Distance is the measurement of that displacement. Hence we end up with the same units of measure (UoM) for different concepts. You can measure both in a linear manner, but one speaks to how far something moved, and the other is the act of moving it. Here is WHY it matters ...

In this next paragraph, I'm going to use the word "product" in its mathematically correct terms; a quick refresher from school ...
Sum is the result of adding numbers
Difference is the result of subtracting numbers
Product is the result of multiplying numbers
Quotient is the result of dividing numbers
And so I continue on ...
Torque is neither a force nor work. Torque is Torque. It is a word to used to describe the twisting potential of force applied at a "distance" from the axis. Chris and I used to argue about this, but I think we'd both agree that really Torque is not either force, nor work. Torque is a PRODUCT of force and distance, but it is NOT a "force" in and of itself; torque is "force x distance" (measured in ft-lb for example). However, Work is also a PRODUCT of force and displacement, but it is properly revealed in the concept of displacement. You cannot have torque if you do not have both force AND distance. You cannot have work if you do not have both force AND displacement. Hence, Torque is not a force; torque is a result of force applied at a distance from an axis.
You can apply 100 lbs of force to a 5 foot lever arm, and you get 500 ft-lb of torque. (linear measurement of distance of the application point of the force relative to the axis)
You can raise 100 lbs of weight 5 feet off the ground, and you get 500 ft-lb of work. (linear measurement of displacement; something moved from one location to another)
The math and units are the same (100 lbs x 5 ft = 500 ft-lb), but the concepts are different because of the difference between "distance" and "displacement".

Again, torque can be static or moving, and still be just as viable. This is because of one key concept that most everyone gets wrong. It's the concept of acceleration. Acceleration is the concept of a rate of change of velocity; commonly expressed as a displacement divided by the time^squared. (Ft / (sec x sec)). But brace yourself for this ...
Things can be acted upon by acceleration, but never move. That is KEY to understanding the entire topic of torque and force and "Horsepower", etc.
If you think I've lost my marbles, I'll straighten you out here.
While you sit in the chair, just what is it that you think keeps you from free floating in space? What keeps the coffee in your mug? What keeps the trucks we drive on the driveway? It is, of course, gravity. It is the attraction of one mass pulling on another. You are accelerating towards the center of the Earth, because the correct definition of "force" is "mass x acceleration". You, the coffee mug, truck truck; they all have mass. And the Earth provides acceleration. So the weight you present in a downward force is in equilibrium from the chair you sit on, the table the mug sits on, the driveway the truck sits on. THINGS DO NOT HAVE TO BE MOVING TO BE UNDER THE INFLUENCE OF ACCELERATION. Things do not have to be moving, to be under the influence of force.

And so, as we know, torque is force multiplied by distance. T = F x D, where the Force = mass x acceleration, and the distance is the linear measurement of the lever arm. It looks like this:
T = (mass x acceleration) x distance.

If you apply 50 ft-lbs to a very tight bolt, the bolt may not turn. It's not because you are not applying force; you most certainly are. The bolt is not turning because it's resistance torque is greater than your application torque. Accurately described, you can be accelerating the bolt by applying a force, even though the bolt does not turn.

But that same 50 ft-lb torque can be applied when motor shaft is moving at a constant rotational speed (steady rpm). As long as the resistance = the effort, nothing will gain or loose speed. But that does not mean torque is always stationary.

The simple reason things move, or stop, is because of "force". You are either accelerating or decelerating a mass to cause displacement; nothing more and nothing less. Things move because the force acting in one vector is overcoming the resistant force in the opposing vector.

The way most all typical vehicles move themselves is because of the concept of converting hydrocarbon energy into linear energy (fuel to piston travel in a cylinder bore). Then the con-rod and crankshaft convert the linear energy to rotational energy; it becomes torque. Then the drive-train carries that energy to the wheel, which then has the tire circumference convert it back to linear movement at the road surface. THAT, my dear folks, is how things move. Force is generated, transferred, and then applied to another location. As long as the force generated at the road surface is enough to overcome the force of resistance (mass inertia, coef of friction and drag, rolling resistances, etc), the vehicle will move.

Horsepower is just an arcane word to describe a specific amount of torque at a specific rpm; that's all. It could be called "pickle power" or "weasel power" and it would still be calculated the same way. "Horsepower" is a mathematical calculation that describes the torque effect, applied to a moving mass, for a specific duration of time. The famous "5252" constant is a complex reduction of how the math resolves the conversion of displacement in radians and time, etc. You can google it if you want to know the exact math, but it results in a unit-less constant of "5252" when applied to torque and rpm.
- An engine that makes 100 ft-lb of torque at 2000 rpm is no more or less powerful than one that makes 200 ft-lb of torque at 1000 rpm; when both are seen at those stated conditions. Both make 38 hp.
- An engine that makes 100 ft-lb of torque at 2000 rpm makes twice as much "power" (38 hp) than an engine that makes the same 100 ft-lb of torque at 1000 rpm (19 hp), because the higher rpm value means the same amount of work is being done in half the time. Both can move the exact same amount of mass, but one does it faster. "Horsepower" does not make a vehicle faster. What makes a vehicle fast is creating torque at higher rpm. The engine does more "work" (described as revolutions represented as radians of rotation) in a set duration (a minute). The numerator grows and the denominator is constant. Hence, more "power".

Anyone whom ever states that "torque is for pulling, and HP wins races" clearly does not understand the physics of it all. What moves things is force. How quickly that force is applied describes the concept of "power". (not horse-power, but the true concept of power, which is work per unit of time).

Which of these two vehicles can pull more trailer weight up a hill, assuming the only thing different is the engine output? (we will assume they have the same trannies, same diffs, same tires ...)
Truck A makes 400 ft-lb of torque at 2000 rpm.
Truck B makes 400 ft-lb of torque at 3500 rpm.
Which truck can pull more load up the hill?
Neither - it's a trick question. The torque is the same for both; neither can pull more load up the hill than the other.
But, truck B will make that trip in less time; it makes more "power".

Different question ...
Which is "faster" of these two examples: (same assumptions)
Car A makes 350 ft-lb of torque at 2000 rpm
Car B makes only 230 ft-lb, but at 3040 rpm
Neither is faster; they make the same "power". (133 hp)
But car A can pull more load, because it makes more torque.

Torque is key to any conversation such as these. You are incorrect, Brian, to state torque "can't actually do anything because it's a static measurement". That is utterly untrue, and a total misunderstanding of how the physics works.

 

Welcome to the 6.0L forum Dave!

 

Boy i forgot what it was like to be i school.
That was a very impressive and informative post. I'm with Bis welcome to FTE.