# Gator's Challenge



## Grumpy Gator (Dec 11, 2017)

_The challenge is this, please explain the best simple definition of :
Horsepower = Newton Meters. And how that relates to torque.  
Please keep it simple. 
Jame's Watt came up with "Horse Power" as a marketing tool to sell his improved steam-powered engines more than 100 years ago.
This being an educational forum my thought is we can do better.
**G**
 EDIT ...My question was not worded right. Thank You Rzbill for pointing that out. _


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## papa-roe (Dec 11, 2017)

That is far above my pay grade.


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## brav65 (Dec 11, 2017)

Here is how I increased the horsepower of my truck... obviously I do not understand what torque or horsepower is.


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## papa-roe (Dec 11, 2017)

You have a better grasp than I.


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## rzbill (Dec 11, 2017)

EDITED

That equality is not quite correct.

You have power equal to torque

POWER is a force (F) over a distance (L) per unit time (T) or in other words (FL/T).  One HORSEpower is specifically 550 lbs force moved 1 foot in 1 second.
TORQUE is a force (F) times a length (L) or in other words (FL). A Newton is a force and a Meter is a length.

To fix the equation it should be (horse)power = Newton*Meter/sec       or FL/T = FL/T

The technique I have shown is called units analysis.  The units of measure must be the same on both side of an equation for it to be valid.  For this analysis, details of meter vs inch are not important, only that they are both units of length (L)  

So...Lets restart.    What is it you are trying to ask??  Horsepower conversion to grain*furlong/fortnight perhaps? 

See RJs post below for more details.


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## Grumpy Gator (Dec 11, 2017)

_ Good that's what I'm looking for expand on that_
_**G** 

_


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## RJSakowski (Dec 11, 2017)

Horsepower is the rate of doing work. Historically, 1 horespower was equivalent to a horse lifting 550 lbs. in 1 sec. and considered the amount of work a horse was capable of on a continuous basis.  Work and energy have the same units, i.e. force x distance / time.  In the metric system the unit is the joule = 1 newton-meter.  In the Imperial system it is the ft.-lb.  One joule/sec = 1 watt and 746 watts = 1 hp.

Rotational motion has an equivalent to the linear motion.  Torque is a force exerted against a lever arm; force x distance.  However even though the units are the same as work, there is a difference which is why you commonly see torque expressed as lb.-ft. in the Imperial system now. The difference is work and power do not have a direction whereas torque does.  

A common relationship  is made between torque and hp.  Torque (in lb. ft.) = hp x 5252 /rpm.  The 5252 is an accounting factor arising from the conversion on minutes to seconds and that rotation as expressed as rev./min  need to be converted to angular displacement measured in radians with 1 rev. = 2 pi radians.

So....  *1 hp = 550 ft lbs./sec = 746 watts *and* lb. ft. torque = hp x 5252/rpm*.  These relationships will fairly well get you through hp and torque

disclaimer:  force, distance, and torque all have direction associated with them.  It is actually the component along the direction of motion that is effective in doing workso there is a cosine factor as well.  

There is an excellent source for learning about things like this called Khan Academy.  https://www.khanacademy.org/
Wikipedea also does fairly well as do some of the engineering sites.


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## rzbill (Dec 12, 2017)

OK Grumpy,
Is this a thread about famous Scots??? (Noticed your avatar data)

I worked in the UK for a Scot (funniest man I knew) and travelled to Scotland many times to install milk bottle blowmolding machines in Bellshill for Wiseman Dairies.


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## Grumpy Gator (Dec 12, 2017)

_OK I edited my first post._
_ The challenge still stands. Who's horse? And what does that have to do with power? _
_I am a wrench and a gearhead. I learned to machine because I wanted better parts built to closer tolerances to go faster._
_Every Friday I go to Choir Practice {Car Club} and hear "Horsepower"  in every other conversation. ..My answer to that is "Let's go to the track and when the light turns green if you get to the other end before me you win". _
_ Now did you win because of more HP or NM or torque or Watts or joules?_
_**G**_


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## RJSakowski (Dec 12, 2017)

Mr. Watt had come to the realization that there was a need to define power as a means of doing useful work, whether it was pulling up miners and ore in an elevator or turning the grist mill. The horse was the accepted method for portable power.  Not being privy to Mr. Watt's experiments, I have no idea as to whether he used a single horse or the average of a number of horses to base his standard.
As to whether torque or horsepower is more important, torque is responsible for acceleration.  Zero to sixty requires a lot of torque if you want to keep times down to a few seconds.  Horsepower is responsible for maintaining speed in the face of energy losses from friction and air resistance.  I have heard it said that a typical car requires around 25 hp. to maintain a 60 mph speed.  At racing speeds, air resistance is a major consumer of energy.  Torque gets you going and hp keeps you going.
Again, hp, newton-meters, and watts are just different ways of measuring the same thing.  Like inches and millimeters and furlongs. A joule is a measure of energy and equals a watt-sec.  3,600,000 of them are a kwh which is equivalent to about $.12 which won't even get you an ounce of beer.


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## rzbill (Dec 12, 2017)

Gator,
As RJ says, high torque is good for acceleration and high HP is good for high top speed.  Good rules of thumb.
Some folks mistakenly come to the conclusion that one can get the high torque (high accel) via gearbox mounted on a small HP motor.
The fallacy in this is that as soon as the motion begins (_motion means *time*_) , the torque drops quickly because the small motor does not have the HP (meaning torque per unit _*time*_) to keep the torque up at the desired level as the speed increases. Acceleration quickly falls off in this scenario.

From a practical standpoint, the street motorcycles I have tuned have focused on midrange and upper midrange torque rather than high top end HP.
I think the same could be done for street cars too.
Good midrange torque (and the associated HP that occurs at those RPMs) makes for a quicker and more pleasant ride because acceleration is easily available at an instant without having to shift gears and reach for top end HP.

And I always liked the beer glasses in the UK that had the legal fill line near the rim.  
I want my $.12 of beer and not a cent less.


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## Groundhog (Dec 12, 2017)

A flat track motorcycle racer friend once explained to me that; "Horsepower is how fast you hit the wall. Torque is how big of a hole you make."


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## eugene13 (Dec 12, 2017)

My avatar is a picture of the valvetrain of a high rpm, high horsepower motor, wonderful if you can put it to the track.  We now race a low rpm high torque motor, it pulls the car off the corner better and dosn't light up the tires, sometimes less is more, and we go faster, just my 2c.


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## JPigg55 (Dec 12, 2017)

I always thought of it as:
More HP=More Speed
and
More Torque=Less Time to get there.


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## eugene13 (Dec 20, 2017)

One more way to say the same thing


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## JPigg55 (Dec 30, 2017)

Here's a link with a decent description.
https://www.popsci.com/what-is-hors...pJobID=1183266375&spReportId=MTE4MzI2NjM3NQS2


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## kd4gij (Dec 30, 2017)

Depends on the size of your horse.


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## Grumpy Gator (Dec 30, 2017)

So if you got a bigger horse does that mean you got a bigger Newton?
**G**


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## Ray C (Dec 31, 2017)

Some horses put out more horsepower if coaxed with apples or carrots.  This is equivalent to putting low-test or Ethyl in your car.   This is a known fact by the way. ().

Ray


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## Groundhog (Dec 31, 2017)

Ray C said:


> Some horses put out more horsepower if coaxed with apples or carrots.  This is equivalent to putting low-test or Ethyl in your car.   This is a known fact by the way. ().
> 
> Ray


The apples and carrots might work but changing octane in your gas will not help horsepower. A higher octane gas will allow you to make changes to your engine that result in more horsepower (increase compression ratio, advance timing, etc.) but octane in and of itself will not make any difference in an engines performance.


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## whitmore (Dec 31, 2017)

Energy is conserved.   That's the first law of thermodynamics, and in the
time of James Watt, it was promulgated by the great American scientist,
Ben Thompson, or as he was known after we booted him out of the
country for his radical politics, "Count Rumford"
.... but that's a side issue, let's keep it simple.

Ben studied machining, he knew it took lots of work to bore cannon, and
the workpiece got hot (though today, we know where to buy a cure for that,
$28 a gallon).   He made the connection.  The work done BOTH made
chips AND heat, but duller tools made less chips and more heat
... but that's a side issue, let's keep it simple.

The 'work' aka 'energy' consumed (the input) was a conserved quantity,
you could total up the heat and chips (the output), and know how much

(1) horse feed
(2) coals from Newcastle
(3) billable electricity
(4) water volume through the flume of a given waterwheel

went in.   Any of those inputs become work, produce the output.

The formula for energy in the machine tool that bored those cannon was:

Energy = Torque * Angular_speed * Time

because nothing would make chips without torque, without movement, without time.
And you can convert (because energy is conserved) from an ideal rope wrapped
around a drum, to

Energy =Rope_tension * Velocity  * Time

because that rope and the drum radius make a torque, and the drum diameter
and Angular_speed = Velocity / ( 2pi * Drum_radius) :== radians per second
which follows from 

Torque = Rope_tension * Drum_radius      and
Velocity = 2pi * Drum_radius * Angular_speed

So, depending on the power-transmission chain, there's lots of similar
formulas, all toting up the energy, or (leaving out time which is common
to all these formulas) relating forces (and generalized force-like quantities)
and displacements (and generalized displacements) with power
(which is truly general, and needs no generalization).

Energy/ Time = Power =  Rope_tension * Velocity 
  can also be expressed as
Watts =   Newtons * Meters_per_second

and with a suitable conversion from SI units to the world of working horses,

Horsepower / (745 HP/Watt) = Newtons * Meters_per_second

Other (generalized forces)  equations for power are all in the form of
a product of an intensive property (that isn't different for an ant or an
elephant, doesn't scale with power needs), and an extensive property 
(which DOES scale).   For economics, it's the extensive thing that costs
you more when you use more power...

Power = Voltage * Current
Power = Friction * Velocity
Power = Dam_height * Water_mass_flow
Power = Torque * Angular_speed
Power = Fuel_specific_energy_content * Fuel_delivery_rate
Power = Horse_daily_feed * Horsies_hired
Power = P40_decay_energy * (Potassium_40_atoms/P40_decay_lifetime)

but unless you are in the habit of powering Earth's volcanoes, that last one is
kinda... esoteric.

Really, I TRIED to keep it simple!   That just isn't my forte.


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## kd4gij (Dec 31, 2017)

Groundhog said:


> The apples and carrots might work but changing octane in your gas will not help horsepower. A higher octane gas will allow you to make changes to your engine that result in more horsepower (increase compression ratio, advance timing, etc.) but octane in and of itself will not make any difference in an engines performance.


 

 Not true today. In todays muscle cars EPA says they have to run on regular 87oct. Put them on a dyno and they fall short of rated HP and TRQ. Put 97oct in and It will hit rated numbers. This is because they are detuned to run on 87. In my mustang I picked up 5-6 hp and 15ftlb trq. Once I retuned it I picked up 20hp and 30 ftlb.


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## Groundhog (Dec 31, 2017)

There is no energy (BTU) in octane. Zero, zip, nada. Therefor octane cannot improve performance. A gallon of gas has about 12,000 BTUs regardless of octane rating - even 110 AvGas. Something else had to have changed (and most dynos are very unreliable).
Octane is a measure of a fuel's tendency to ignite under pressure. Lower octane gasolines ignite at lower pressures, which is why higher octane gas helps reduce knocking from compression.
There may be other diferences in the 2 blends of gasoline that affected the power from the fuel, but it wasn't octane.


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## JPigg55 (Jan 1, 2018)

As stated, a higher "Octane" level raises the auto ignition temperature of gasoline, not the energy contained within.
Since an engine cylinder is a fixed volume based on bore and stroke, some modern high performance engines can sense knock and adjust (retard) the timing to prevent knock (pre-ignition), though, in so doing, decreases performance.
With higher octane fuels, the engine controls can advance the timing slightly. This does two things:
1. It effectively increases the compression since the fuel/air mixture is already combusting/expanding before pistol hits top dead center.
2. It burns the fuel more completely releasing more energy.
The net result being a measurable increase in both torque and horsepower.

Much of this has to do with the "Speed" of combustion. When a spark plug fires, the fuel/air mixture burns at a given rate based on the temperature of the mixture also known as "Flame Front Speed".
Another factor is the "Volume" of the combustion chamber. If you could see the crank shaft and pistons in an engine, what you'd see is that as the crank shaft rotates the velocity of the piston would increase as it went from top dead center until it reaches 90 degrees of rotation of the crank. From 90 degrees to 180 degrees (bottom dead center), it downward velocity of the piston reduces. This process repeats as it travels back up from 180 degrees to 360 degrees of crank shaft rotation.
When the RPM of an engine increases, the change in volume per unit time increases since the piston is moving up and down at a faster rate. This has the effect of reducing the "Compression Ratio" of the engine during its cycle. Engine designers account for this (to the extent possible) by "Advancing the Ignition" of the spark plugs. This causes the fuel/air mixture to start combusting before the piston hits Top Dead Center. During the combustion process, the gases are heated and expand. If the piston is still moving upward (compression stroke), this increases the pressure in that volume increasing the pressure and temperature in the cylinder which causes the combustion process to happen at a faster rate which, in turn, increases cylinder pressure which applies a greater force to push the piston down.
With lower octane fuel, pockets of the fuel/air mixture can ignite at a lower temperature. If the piston is still on the upstroke when this happens, it raises the pressure in the area above the piston which reduces the velocity of the pistons upward travel, acting like a brake. This is what causes "Engine Knock". It's the sound resulting from the gases impacting the piston as it is still traveling upward during the compression stroke.
If the timing is advanced too far, the condition gets worse and can lead to engine damage. Retard the ignition to far (sparks later in the cycle) and the cylinder volume is increasing faster than the flame front reducing the combustion rate which robs the engine of power.


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## eugene13 (Jan 1, 2018)

One time I had some left over 110 octane leaded race gas, so I used it in the riding lawn mower. It went up the hill better and seemed to get better mileage (Mowage).  I think the blend was energy denser than regular unleaded gas, more BTUs. On a side note, The song Proud Mary, by CCR has a verse: Cleaned a lot of plates in Memphis, Pumped a lot of tane down in  New Orleans.  Do you think the word "tane" is a reference to gasoline?


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