(rock music) - [Man] Okay.
- [Guy] Feeling good? - [Man] Feeling good.
(indistinct).
- (laughs) Are you feeling good about launching this guy?
- Not really, especially with this clutch.
But, whatever.
- Right, you ready? - Yeah.
- Here we go.
Three, two, one, go!
(car engine revving)
- We all know that if you wanna go faster,
you need,
James.
(screaming)
(grunting)
- [All] More power!
- But if that's true, then why are Miatas
so quick on track days?
Why can Tacomi beat a GTR in the downhill in a Corolla?
Could it be that less weight is more important
than more power?
Well, we're going to look
at how each affects a car's performance
and find out if it's better to be featherweight,
or powerhouse.
I'm a power bottom.
(laughs) let's go. (lottery machine bleeping)
(smooth jazz)
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Weight and horsepower.
When you think about it, they're actually just two forces.
Weight is the downward force of gravity on a car
as determined by its mass.
And horsepower is a measurement
of work produced by the engine,
which is just a force applied over a specific distance
over a certain amount of time.
One horsepower is the amount of work
it takes 3,300 pounds to go one foot in one minute.
Or an average 3,300 pound car to go one foot in six seconds.
If you play around with the variables
on either side of that equation,
it's easy to see that you can go further or faster
with more power or less weight.
Now, on the surface,
the relationship between power and weight
is pretty straightforward.
Every car has a constant weight and a peak power.
The ratio of the two is called the power to weight ratio.
James, he did a D list on cars
with interesting power to weight ratios a while back.
You should check it out after you watch this video,
but for those who haven't watched it,
the power to weight ratio works like this.
Since it's expressed as weight over power,
the lower the number, the better the ratio.
Cars that are really heavy
and don't have a lot of horsepower,
have a high power to weight ratio.
And cars with lots of power
that are also really lightweight,
have a low power to weight ratio.
And in the middle,
you have cars that maybe have one or the other.
For example, a Lotus Exige and a current Mustang GT
have very different specs in terms of horsepower and weight,
but their power to weight ratios are about the same.
So does that mean that they're as fast as each other?
Well, hold on a second.
It's a little trickier than that.
If you were looking at a drag race, then sure.
Equal power to weight ratios
would yield similar performance.
But other racing disciplines are different.
On a road course, your horsepower doesn't help
when you're braking or cornering.
You can't benefit from your horsepower all the time.
Weight, on the other hand, it's different.
It's constant.
It doesn't change with application.
I wish it did.
Could you imagine being all skinny whenever you wanted?
But then someone tries to kidnap you
because you're the son of a diplomat and then, boom.
Now you're a 600 pound guy.
Try to move me now, you suckers.
Besides, my rich dad doesn't have kidnapping insurance.
You're not gonna get anything from me.
Then they cut your tongue off and cut your fingers off
and then saw them (beep)
Anyway, so since weight is always a factor
and horsepower is only sometimes a factor,
that means weight is better, right?
Right, is that right?
Actually, we're not done yet.
Back when we did our episode
on why it's almost impossible to go 1,000 miles per hour,
we talked about wind resistance
and the drag created from punching through air
as you drive along.
Now, this drag increases quadratically with speed.
It's not exponential growth.
I know people throw that term around
like it's quadratic growth.
Okay, nevermind.
But that force is the square of the speed.
The mass of the car, it isn't increasing,
but the weight of the car is increasing
due to the air pressing down on top of it.
And that can only be overcome by more horsepower.
At high speeds, weight begins to matter less and less.
See what's really affecting the car
isn't so much the weight as it is the inertia.
Inertia is an object's resistance to change and acceleration
in that is directly tied to an object's weight.
But once an object is already in motion,
the effective inertia is minimal.
As the car accelerates, its acceleration tapers off.
The most G-Force is created
right at the initial point of acceleration.
And after that, everything begins to equalize
as the car's mass begins to move.
This is why you can't do a burnout
when you're rolling along at 50 miles per hour.
Your car has much less acceleration and torque
than it does when it's at a standstill.
Which actually brings me to my next point
and the limiting factor for both weight and horsepower.
And that is your contact patch.
That's your tires.
It's just a cool way to say tires.
You're like, "Hey, I've got a big contact patch."
You're like, "Oh, sick dude.
I got a tiny contact patch."
And you're like, "Hey dude, it's fine, man.
I love all tire shapes.
Tires are universal, man.
You know, all shapes and sizes.
They're all beautiful.
They all smell good."
And we can get into a long discussion about tires.
But for the purposes of today,
all you need to know is that a tire has a certain threshold.
An amount of force that if you push beyond that,
the tire is gonna slip.
This is the coefficient of static friction.
Every material has two friction coefficients.
You got static friction.
That's the amount of force needed to move it.
You've got your kinetic friction or sliding friction,
which is how much force is needed to keep it moving
once it's already moving.
The coefficient of kinetic friction is always lower
than the coefficient of static friction.
If you've ever pushed
a heavy piece of furniture or your mom,
and it all of a sudden jerked forward,
that's you overcoming the coefficient of static friction
and moving into the realm of kinetic friction.
Now for tires,
they're in static contact with the ground.
The wheels, they roll to keep the tire and asphalt
in constant static friction territory.
For the average road tire,
the coefficient of static friction is 0.7.
That means that to stick to the ground,
a tire can only handle
seven tenths the force of the weight that's acting on it.
In a 4,000 pound car with perfect weight distribution,
each tire would have 1,000 pounds of force
pushing it into the ground.
And therefore could only handle 700 pounds of force
before the tire slip.
This is why the tires are a limiting factor.
If you're braking heavily,
the weight of the car goes to the front two tires.
They now have the force
of the inertia of the car acting on them.
The more the car weighs,
the more force you're asking
those two front tires to handle.
Eventually, you can have too much weight for the tire.
And on the power side,
you can have too much power for the tires.
Rear wheel drive cars with too much power
can have problems getting on the power too early
out of a corner 'cause their weight is on one side
and delivering more force to that outside wheel.
They'll send you to a nice little spin.
I did this one time in my catfish Camaro at Buttonwillow.
And Canaan loves to show people
how I messed up at the track one day.
So to recap, mass is a constant of the car,
which only affects the car during changes in motion.
Accelerating, decelerating, and changes of direction.
Horsepower only affects a car during acceleration.
Different types of racing
favor the two sides of the power to weight ratio.
A high horsepower V8 might be really good at an oval track,
but a lightweight hatchback might be good at auto cross.
Now, there are plenty of other things
that affect a car's speed on track.
That's your suspension setup, tire choice,
mechanical grip, aerodynamics, gearing, power band,
and not to mention, driver ability.
But now we've got a better understanding
of power in weight's relation to performance.
What's that?
You want proof of that?
Oh, I got ya.
No problemo.
So to help demonstrate a practical example of this,
we're out here in the middle of nowhere
and we got two very fancy cars.
We have my lovely catfish Camaro,
and we have our rider, Joey Russell's Yaris.
So we got both of these cars weighed.
And then we went down to our buddies at EF1 Tuning
where Richard dynoed both cars
so we could get an accurate horsepower to weight ratio.
So my catfish has a better horsepower to weight ratio.
So in a functional test, say from zero to 60,
it's gonna do better than the Yaris.
But all that power is irrelevant
when you're going from 60 to zero
in a braking test where mass matters most.
And that's where the Yaris is gonna beat the catfish.
So we came out here today
to test if that really is the case.
You're ready? - Let's do it.
All right.
(door banging)
All ready.
- God.
- It's not a total death trap.
- Damn.
(door bangs) (laughter)
I feel like I just broke something.
(rock music) Right here we go.
Timer, set.
- All right, you ready?
- You good, yep on you.
- Gimme, gimme,
gimme that count.
- Okay, three, two, one, go.
(car engine revving)
Okay, 9.42.
(laughter)
- Okay, a little too much wheel spin.
- All right, are you ready? - Yeah.
- Here we go.
Three, two, one, go.
(car engine revving)
- Stop, 7.11.
- 7.11, okay.
- I'm actually, getting nervous now 'cause,
he's got big front calipers.
(tires screeching)
All right.
Right there?
- [Jeremy] Mark it.
- Mark it, all right.
- Aww, little guy. (car engine revving)
So we're doing our 60 to zero test.
This is where my Camaro stopped.
Joey just went out.
He's gonna do his run.
If we did this right,
Joey's car is gonna stop sooner than my car.
It weighs less, so it has less mass to stop.
But we'll see.
(Joey cheering)
Look at that. - Look at that!
I guess it goes to show that,
power's not always important.
Yes, more power, baby.
But also, less weight baby.
- In practice,
weight and power are only two factors
among many that go into a properly set up car.
Ideally, you always want more power and less weight.
But knowing what each does to a car is important
for understanding how it will react on the track
and on the road.
All I know is that my catfish is fricking sick looking, man.
Who's in Southern California
and wants to go do a track day with me?
I gotta get my catfish out there more.
I gotta do better.
I gotta be a better driver.
Thank you guys so much for watching this episode of B2B.
Follow is here at Donut on Instagram at Donut media.
Follow me on Instagram at Jeremiah Burton.
Thanks so much for watching guys, until next week.
Bye for now.