hello everyone and welcome in this video
where you're going to be talking about
the difference between torque and
horsepower and we're not going to be
using any strange analogies and very
minimal math just talking about theory
and keeping it easy to understand so
we'll start things off with torque
torque is simply a force applied at a
distance you can think of it as a
twisting force so if you're trying to
tighten something down using a wrench
you apply a force you press down at a
distance the length of that wrench and
that supplies a torque at whatever
you're tightening same idea with a
socket wrench so if you're tightening
down a bolt you apply a force at a
distance and that supplies a torque to
that bolt to fasten down that bolt now
the same thing is happening with your
engine so combustion combustion within
your cylinder is what's supplying the
force pressing this piston down and then
that piston is pressing down on a
crankshaft so as you can see you've got
your force pressing down you've got your
distance where it's pressing on the
crankshaft the axis of rotation is the
center here the piston is pressing
offset from that center so at a specific
distance and combined that gives you
your engine torque force pressing down
at a specific distance that gives you a
twisting force that's the torque that
your engine is making now torque can be
manipulated very easily by using gears
or by using leverage for example so this
will supply you know with my the maximum
amount of force I can supply to it a
certain amount of torque but then if I
were to use something much longer now I
have more leverage I can press at a
greater distance
and since torque is force multiplied by
distance the torque here is going to be
significantly greater okay so what is
power and how do these two relate well
power is the rate at which work is done
so what does that mean well if I move
this car from here to here I've done a
certain amount of work I've moved this
from here to here now if I do it very
slowly it doesn't require much power if
I do it very quickly it requires more
power now ultimately I'm accomplishing
the same thing I'm moving the car from
here to here but I'm doing it faster the
rate of work is greater therefore it
takes more power so more power going
quickly than going slowly so power
ultimately is what gives you speed
what gives you acceleration now the two
are connected so in in our context he
are looking at our engine we have torque
as a force pressing down acting at a
distance well how fast that's happening
is our power so that's our rpm so
horsepower is torque multiplied by rpm
so how often this interaction is
occurring and so how fast is this
spinning while we're still getting that
consistent force acting on the piston so
the faster it spins supplying that same
amount of force at that same distance
the more power we're going to make okay
so how about an example to help explain
things further let's say we have two
different vehicles that are exactly the
same now I know these look different but
we're just going to pretend they're
exactly the same nothing about them is
different except this one has 200
horsepower and a hundred pound feet of
torque those are the peak numbers this
one has 200 pound feet of torque and a
hundred horsepower so half the power
twice the torque this one has twice the
power half the torque which one is going
to accelerate faster assuming both of
them have the same mass and everything
else about them is equal well the one
with more power is always going to be
quicker because that is the rate at
which work is done that's how quickly it
can accomplish work move something from
one place to another it can move it
faster now this one has more torque
great but as we know torque can be
manipulated through gearing so gears act
just like leverage so while this doesn't
have as much torque as this if I'm
applying torque to something I my power
doesn't change how strong I am doesn't
change but I can use leverage just like
cars can use gears to make more torque
so this car with twice the power but
half the torque can use gears to
accelerate faster so it can use a longer
you know leverage arm a greater a more
aggressive gear ratio so that it can put
that power down and ultimately because
it makes more power it can do more work
more quickly it will be the faster car
okay so now let's talk about horsepower
and torque curves because when a
manufacturer gives you a horsepower and
a torque figure they're just giving you
the peak figure for each of those
they're not giving you you know
the amount of torque that that produces
across all of the engine rpm range and
so if you look at a torque curve it'll
have some peak along that curve with
respect to rpm so that's the engine rpm
in which the force pressing down on the
piston is at its greatest so that's peak
torque and what that means if you stay
within a set gear if you're in one gear
let's say you're in third gear you will
feel the the force pressing you against
your seat will be the greatest at peak
torque now that's assuming you're
staying at a constant gear ratio
you're staying within one gear so now if
you look at the horse power curve
overlaid over that torque curve at some
point peak horsepower will occur and
that's when the engine is doing the most
amount of work it can do and so at this
point you may think okay if I want to
accelerate fastest I need to be at peak
torque so you want to be at that peak
spot well that's only true for a set
gear and that's only within that gear if
you can manipulate the gear ratio let's
say peak torque is right here but peak
power is over here later in the RPM
range you can sacrifice torque but get a
more aggressive gear ratio and
ultimately accelerate more quickly by
accelerating at peak power so why is
that well that's because you're
multiplying your torque by the gear
ratio so you have peak torque multiplied
by a lower gear ratio versus a lower
torque but multiplied by a significantly
higher gear ratio at peak horsepower
that will give you your peak
acceleration so for example CVT
transmissions which can adjust the gear
ratio constantly if they adjust that
gear ratio to maintain the engine at
peak horsepower they will accelerate the
fastest rather than if you were to
manually shift gears or have an
automatic transmission which shifts
between gears and you'll feel that peak
sensation that peak force against the
seat at peak torque as you cross over it
but the actual true amount of peak
acceleration that's possible with that
engine would be if you manipulated
gearing if you manipulated leverage to
allow you to be at the highest
horsepower level with the most
aggressive gear ratio possible so a
quick review torque is simply a force
acting at a
distance horsepower is how quickly you
can accomplish work now both of them
require each other they're a function of
each other
horsepower is torque multiplied by rpm
so you've got a specific torque and then
you spin the engine at a certain speed
that will give you power and so
ultimately they are you know they
require one another you can't have
horsepower without torque but the most
important figure if you're looking at
how fast will a car be able to
accelerate what will its top speed be
that comes down to power because that's
telling you how quickly can you
accomplish a certain amount of work so
hopefully this has cleared things up the
differences between torque and
horsepower if you have any questions or
comments feel free to leave them below
thanks for watching