Well, im no Certified Engineer but I was always told its not really the HP that matters on the motor, its the tourque....The way i hear it go is Tourque is how far it will take you, HP just gets it there faster....Is this assumed to be correct? Sorry, didn't have time to structure a formal question .

 

Torque is leverage against a rotating axis.

HP is the measure of work using weight, time and distance.

Some guy figured out a way to calculate the measure of HP from an engine by RPM x Torque / 5252 = HP.

At the time, horses did all the work, so they had to have something to compare it to. If they would have used cats, the it would be Catpower. Dogs - Dogpower.

If you really want to see the difference, go to http://auto.howstuffworks.com and look it up.

Here's an article on it also...
http://www.carcraft.com/techarticles/868/index.html

 

Right. Another way you can look at it is this. Torque is the amount of perpendicular force being applied at a certain distance (Force times distance, general form). So if you have 400lb-ft, you have 400lb of force applied at 1ft perpendicularly, and as you know the more force applied, the more tendency the axis has to rotate.
Horsepower is power which is a measure of energy in terms of time.
Power=Work/Time
Soo, horsepower is just the amount of energy your engine is putting out in a certain amount of time. There is a difference, and without torque, your engine wont even turn your wheels over.

 

To answer your question more simplistically. A high Torque # is more important for getting you moving off the line, going uphill, towing etc. Higher HP helps more after your moving. Thats why our old third gens can still take some of the newer cars from 0-60 or 1/4 mi even though we have less hp we usually have more tq.

 

Since horsepower is a relationship between force, distance, & time, the engine that puts out more horsepower as it's going down the 1320 will get the same mass car there quicker.

Another tidbit: Nobody measures horsepower. They measure torque, and calculate horsepower based on the RPMs at which the torque is being produced (per AJ's formula above).

 

exactly, many people dont understand horsepower and torque. torque is a tangible thing, you can feel torque, whereas horsepower comes from a mathmatical formula.

 

WORK accelerates mass and HP is a measure of work. TORQUE is a measure of twisting FORCE. Combine TORQUE and RPM (movement) and you have performed work (HORSEPOWER.)

When asking for TQ at a given RPM, you're really asking for the HP. A given TQ at a given RPM is ALWAYS a given HP...no matter what the engine.

It is the HP number you need to be concerned with. THAT is your measure of work performed and potential for work (acceleration.)

 

A lot of people focus to much on HP. Whenever you do any mathmatical analysis on an IC engine you rarely even use hp. There are much more important factors to consider like mep, bmep, imep, and bsfc. These parameters tell you how the engine makes power in relation to internal volume and displacement. It sorta tells you what an engine does with what its got. You guys are pretty much on track but to get a bit more technical torque is defined as the measure of work done per unit rotation of the crank (in radians). The best way to determine power is with the parameters I listed above. The mep or mean effective pressure tells you how much work is done per unit volume of engine size. Two factors that branch off of this are the bmep and imep which tell you the net work per unit displacement volume of the gas during compression and expansion and external shaft work done per unit volume. These are much more important than any dyno hp number. They tell you how good the engine really is. As an automotive engineer you are expected to do this stuff on a whim to develop the best possible engine combo. I geuss to not be technical you can say that torque is the power your car makes but hp is how fast you build that. Remember, farm tracktors and semis make serious torque but don't have the ability to accelerate that torque per short units of time. Thats where poepl get the two comfused.