How do Torque and HP differ?

Mopar Racers Forum

  1. 70DusterBob

    70DusterBob Well-Known Member

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    I recently made a modification to my Duster. I went to a Chassis Dyno for some test runs. Before the mod at 2,800 RPM I was getting 112.72 HP, not a lot, but my 360 is only slightly modified. After the mod I got 139.99 HP at the same 2,800 RPM. An increase of 27.27 HP There was a slightly bigger increase a lower RPM, on some or the runs, but the dyno operator said that this was the most consistent increase and reliable increase to look at.

    Also at 2,800 RPM my torque, without the mod was 207.06. After the mod it was 257.19. An increase of 50.13 Ft Lbs of Torque. The Duster really takes off a hell of a lot faster. I don't have a track nearby to test it on for ET difference, but the operator said the increases could make as much as a 1-2 second difference in ET on a 12-10 second car. Is that accurate?

    I was also wondering how HP and Torque differ in moving the car, like if you have a greater increase in HP and less of an increase in Torque, is that better than a greater increase in Torque and less of an increase in HP?

    How do Torque and HP differ in their ability to move a car more quickly down the road?

    Thanks...
     
  2. IQ52

    IQ52 Well-Known Member

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    • JBurch

      JBurch Well-Known Member

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      A very simple explanation is: torque is work................horsepower is work done over time
       
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      • Cope

        Cope Fusing with fire

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        Horse power is how fast you hit the wall, torque is how far you push it...

        ;)
         
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        • 67Dart273

          67Dart273 FABO Gold Member FABO Gold Member

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          Horsepower is merely a mathematical computation derived FROM torque. Google the number "5252" This number links torque and HP. Dynomometers do NOT measure HP. They compute HP They measure, amoung other things such as instruments for air and temp conditions, engine temp, etc etc........

          but the BASICS of a dyno for engine performance is ONLY TWO FACTORS:

          torque, and RPM. Period.

          HP = Torque x RPM ÷ 5252

          ++++++++++++++++++++++++++++++


          To put this into perspective, then, the RPM factor gives you a chance to compare machines with BIG differences, from say, a huge, low RPM antique "hit miss" engine, to a screaming, 15000 RPM tiny turboed 4 whanger.

          You can gear the screamer way way down to produce the same shaft speed as the old "hit miss" and compare the shaft torque output so to speak
           
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          • 70DusterBob

            70DusterBob Well-Known Member

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            Thanks,

            Welp I'd say that answered the question. After reading that, I gather torque is what the engine produces by the force of the piston acting on the crank, while torque turns its power into HP through the gearing. Speed is the result of the torque acting through the gearing which produces HP at different rates for different purposes...

            Sound about right?
             
          • 70DusterBob

            70DusterBob Well-Known Member

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            Thanks,

            This article posted by IQ52 explains in detail what you just said:

            http://auto.howstuffworks.com/differ...horsepower.htm

            Makes sense, torque is produced by the force of the piston acting on the crank from what I gather, the gearing turns that torque into HP at the wheels for different purposes. An 18 Wheeler may have as much torque as a dragster, it moves much slower but can move a lot more weight. A dragster goes much faster but is much lighter.

            Appreciation Granted
             
          • 70DusterBob

            70DusterBob Well-Known Member

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            From what I gather, the gearing turns the torque the engine produces into HP at various speeds for different purposes.

            I PMed someone and asked how much torque that would be in first, since the test was in third, and he said in first it would calculate to be around 122 ft lbs. That feels like the difference I am feeling in the mod in first gear, I am moved much quicker, with more force than in third, but in third I am going much faster, yet at a slower rate of increase in speed it seems.
             
          • JBurch

            JBurch Well-Known Member

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            • ir3333

              ir3333 Well-Known Member

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              HP numbers are used for "wow" factor, torque pins you in your bucket seat!
              a long time racer who's opinion i hold in high regard often said his high HP
              builds rarely et'd well.
              .. good torque with less HP wins races
               
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              • Woods74

                Woods74 Broke Senior

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                Here we go again...
                 
              • RustyRatRod

                RustyRatRod Weenie idiot loser. FABO Gold Member

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                Torque is how fast a fart moves out of your butt. Horse power is how much that fart blows your pants up on the way out.
                 
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                • jimjimjimmy

                  jimjimjimmy lobsterman FABO Gold Member

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                  that about splains it
                   
                • 70DusterBob

                  70DusterBob Well-Known Member

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                • 67Dart273

                  67Dart273 FABO Gold Member FABO Gold Member

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                  I'm trying to tell you HP is simply a mathematical abberation of torque over TIME. That is why the HP formula has rpM which means "per MINUTE"

                  One reason, EG that the HP peak is above the torque peak, is from RPM. That is, the MATHEMATICAL product of work over time can be greater at less torque because the "less torque" is happening at a higher RPM. "It's the product." Multiplication, that is.
                   
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                  • RustyRatRod

                    RustyRatRod Weenie idiot loser. FABO Gold Member

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                    They could have locked the thread after post #2. Just click the link. There's your answer.
                     
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                    • Oldmanmopar

                      Oldmanmopar Going left turning right FABO Gold Member

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                      Torque is the strength to move something. Horse power is the energy to keep it moving.
                       
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                      • moper

                        moper FABO Gold Member FABO Gold Member

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                        Torque is the empirical measurement. You cannot measure horsepower without taking into account the torque figure over a set amount of time. The "5252" number represents the output of an equasion based on converting James Watts' estimation of how much work 1 strong horse could do as indicated by how far a 150lbs weight could be lifted in one minute. Horsepower is "work over time".
                        So torque is the figure of actual power output at any one point in time.
                        Horsepower is how much work that torque can do over a set number of rotations per minute.
                        In terms of a race car - Horsepower is king.
                         
                      • T56MaxTorq

                        T56MaxTorq Well-Known Member

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                        Torque moves an object. While horsepower sells it.
                         
                      • Lelo Dart

                        Lelo Dart * FABO Gold Member

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                        OK just to try to understand, which would be faster, 300 hp 400 lb torque engine or 400 hp 300 lb torque engine, 1/4 mile same setup?
                         
                      • krazykuda

                        krazykuda Well-Known Member FABO Gold Member How-To Section Editor

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                        You measure torque on a dyno, then calculate the horsepower from the torque...


                        The definition of torque:

                        When you wake up with morning wood, and have to pee real bad and can't wait for the "wood" to go down. As you push down on your shaft to pee, you have to spread your legs so you don't shut off the stream and don't miss the toilet.... :banghead:

                        Pushing down on that little "lever" can make you spread your legs wide.... Now that's torque.... :violent1:
                         
                      • Woods74

                        Woods74 Broke Senior

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                        /thread
                         
                      • yellow rose

                        yellow rose Doctor of Thinkology.

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                        Every single time the HP is faster. Think about it. You are trying to do work in less time. how is time. I take HP over torque every day of the week and all day Sunday.

                        The meat heads will come on here and talk about torque but don't buy it Horsepower is your friend. And RPM is horsepower's best friend.

                        Never give up HP for torque. Unless you are a bench racer.
                         
                      • moper

                        moper FABO Gold Member FABO Gold Member

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                        Odds are, all else being equal - the higher torque will be quicker, the higher hp car will be faster. However, if each package could be optimized for their respective pacakages, the HP car would be quicker and faster.
                         
                      • 70DusterBob

                        70DusterBob Well-Known Member

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                        I think Moper hit the nail on the head of my question...

                        My HP and Torque were the same at 4400 RPM 272 HP and 272 Ft Lbs. At 2860 RPM the Torque was 257 while the HP was 140. RPM has everything to do with the gearing of the trans, rear end gears, and size of tires. The gearing of the car has everything to do with how quickly you can go from 0-100, thus the more gears you have the quicker your car can go, provided they are synchronized correctly with the engine's output. If I had a 6 speed, while someone else had a 3 speed, and both top gears were set to top out the engine at 100 mph, the 6 speed would definitely win.

                        It seems to me that Torque is required to "manufacture" HP with the right gears. You can't go anywhere without HP, but you can't get HP without Torque. If you ask me, gears are the racer's best friend, behind an engine with a lot of Torque. I think, and this is just me, but I think RPM's do have a lot to do with HP, while the size of the motor, CID, Bore, Stroke, Intake, Cam, Air/Fuel provided, all go into how much Torque it can produce, how quickly you get that Torque to the ground is gearing.

                        I could be wrong, but seeing how the dyno printout suggests that it is the gearing that manufactures HP out of Torque by converting RPM into rubber burning power, I think RPM + Torque manufacture HP too.

                        I don't know how everyone else's car is, but every car I have been in accelerates quicker the faster the RPM's, up to a point. After the engine can't breathe any quicker, HP and Torque fall off. I think the trick is to get the gearing to match the breathing capabilities of the engine, like low RPM Dual Plane vs Higher RPM Single Plane intakes. If the gears match so as to maximize the breathing of the motor, I believe you will find the quickest, fastest car is the one that breathes the easiest with the right gearing. IMHO But I could be wrong...
                         
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