Torque

[collindow]

Rather off topic, I know, (this is the only online forum I'm a member of, and ya'll are so knowledgeable in general) but I'm curious, do any of you guys happen to be knowledgeable at all about the relationship between torque and horsepower? I've been reading about it, but I can't make heads or tails (especially at this time of night!) of it all.

I'm just trying to figure out why my truck, with a 250hp V8, gets about 100 ft/lbs of torque more than my roommate's car, with a 240hp V6. (Me: 2001 Dodge Dakota. Him: 2006 Chevy Monte Carlo.)
We have something of a "my vehicle is better" thing going on. I only just found the numbers telling me this, and I want to be able to explain, at least a little, why my truck has so much more torque.

And if nobody has any idea, well, hell, light up a bowl and forget about it, because it's not important!
Thanks,

Collin

 

[wolfscout]

how much torque to HP is dependent up on how it's geared. The truck is geared lower for pulling power. The car is geared higher for speed. is simple really.

edit to add tractors are geared even lower for even more torque for less power. Toss in the diesel engine in that mix and you get even better power and performance at low torque.

 

[collin]

Torque and horsepower are two different things and are not related.

They are units of measure.
A unit used in comparison of temperature is "degrees".

A unit used to compare lengths, stop it, is "feet".
A unit used to compare twisting motion is torque.

A unit used to compare power is horsepower.
Clear as mud I bet.
If I remember correctly the term horsepower came from the power of a draft horse turning a mill wheel, it was a measure of the power of the horse.

Torque is measured in pounds per foot and would be; the measure of the power it takes your extended arm to hold a bowling ball out in front of you.
Torque on an auto comes into play when you first mash on the accelerator, torque breaks the tires loose and spins them on the pavement...burning rubber. Torque is that feeling in the seat of your pants when you dump the clutch.

Horsepower is the power the engine is producing to cause the torque.
Not easy to describe. Sorry, I'm just an old gear-head,...not a physics major. :mrgreen:

 

[puffintuff]

Without doing any research and from what I recall, torque is the centrifugal

force (power) generated at the wheels. I could be wrong though.

 

[fred]

The posts on torque and horsepower are correct in the facts. As an

old motorcycle enthusiast, I'll add another perspective to the discussion.

If you graph both of these measurements, as they relate to engine rpms, the

torque curve has the greater degree of acceleration. Generally, the

intersection of these two curves occurs @ 5200 rpm. What this means, is that

up to 5200 rpm, you are riding on the engine's torque. The horsepower takes

over at this point, as the dominant force. Four cycle engines spend the majority

of time in the torque power range, as they use high displacement, longer stroke

pistons, like what you find on Harley Davidsons. Smaller displacement engines

with shorter stroke piston travel rely on higher rpms to develop horse power, as

they have little low end torque, such as Hondas and Kawasakis.

 

[ejames]

I agree with Fred. Long stroke motors will make more low end torque,especially in larger displacement motors.Does your truck have the 360 (5.9 liter)? If so the 360 is the longest stroke Mopar smallblock ever built with a 3.58" stroke,all other Mopar small blocks used a 3.31" stroke.The Magnum 360 make 330 lbs.ft. Only the 340 CI motors of the late 60's-early 70's made more torque--340 lbs.ft.

 

[collin]

Regarding the differences of torque and horsepower, try this relationship.
It's Saturday afternoon and you and your wife are carrying in the groceries. You both carry the sacks close to your bodies because you know that if you hold them out at arm’s length, they’ll be too heavy to carry.

This is due to the “torque” it riquires from your shoulders. The torque required by either of you to hold sack at arm’s length..is exactly the same.
However you have more “horsepower” than your wife,…so you have an easier time carrying the sacks in the house.

 

[bowhatchie]

Torque gets the car moving... the more torque the faster it gets moving.... Horsepower is what keeps it moving the more horsepower you have the faster it will move...or so I HAVE BEEN TOLD..By no means am I an expert on this..nor much else for that matter!!!

 

[flat4driven]

For the 21 years I've been obsessed with cars, this has been one of the hardest things to explain to someone. To simplify it greatly, think of torque strictly as "force". Think about how a torque wrench works; it requires so many pounds to "force" the nut or bolt into place. Horsepower is the "strength" produced by an engine or object. Hopefully that helps some.

 

[stacen]

Everybody is describing the phenomenon of tourque and horsepower correctly, I'll add my 2 cents as this is how it made sense to me when i first started thinking about it. I hope one of the descriptions is the one that lets you "cotton on" to the concepts. (I know sometimes need to try a bunch of analogies before i truly "get" a new concept.)
Tourque is a rotational force. It is measured by the amount of force exerted at a right angle to a radius. It is measured by the amount of force and the distance from the center of the circle the radius describes. The way I came to get my head around it was to think of how torque is measured, foot pounds IE one pound of pressure pushing down on a lever extending 1 foot from a pivot point (like the groceries and bowling ball examples above). Just imagine the strength with which an engine can push down on the off set sections of it's crank shaft.
Horsepower is an amount of work done in a fixed time. The way this relates to engines, and your question is sort of like this, Imagine 2 engines, each has the same torque 50 ft/lbs (the strength at which they turn the crankshaft) engine A can operate at 2000 RPM and engine B can operate at 4000 RPM. Engine B has twice as much horse power as engine A (can do twice as much work in the same time) This is because each revolution of engine B is happening with just as much strength as in engine A, but engine B is making twice as many turns per minute as engine A therefore more work is getting done in the same amount of time.
You can see that there is a relationship between torque and RPM and horsepower. you can have 2 vehicles with the same Horesepower and very different torques that will be better suited to different jobs. EG a 1000HP tractor with have high torque torque and low RPM and is suitable for pulling heavy loads, A race car will have the same 1000 horse power but less torque and greater rpms and will be great at going very fast. this is a bit oversimplified but hope it helps.

 

[lyst36]

When I saw this question I knew there would be a ton of guys on here with the answer. I guess pipes and mechanics go hand in hand.

 

[igloo]

The 3.9 chevy uses dual overhead cams there for it can make horses and quick torque . I would assume your dodge is a 318 cubic inch with a single cam . Your truck makes low end torque due to more cubic inches . 3.9 vs 5.2 = 100 lbs differance in torque . It takes a lot more cubes to make torgue than it does to make horses . As far as gearing it is only used to make hp ratings for the most part . The monte may go faster but it will not pull itself out of a mud hole . But hey after 30 years of selling parts for everything from a Briggs and Straton to a Wasilla I could be wrong . Most class 8 trucks only make about 500 horses with 1400 ft lbs of torque and most do not go over 1800 rpm at least not for long they all have about 850cu inches . Hope this helps . How fast you want to go only depends on the thickness of your wallet . On a quiet nite you can hear a ford rust . If you want to go in circles drive a chevy , if you want to go fast in a straight line drive a ford , if you want to go really fast for just a little while blow up a dodge .lol

 

[collindow]

Yeah, mine is the Magnum 5.9. This has helped a goodly bit, thanks everybody! Still haven't quite gotten my head around it, but I'll keep on working at it.

 

[igloo]

Short version , Cubic inches and compression ratio = torque . RPM = Hp .