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About This Quiz
How can you deal with being in the spin zone? Knowing your stuff about the twisty forces that help make cars go can get really technical, since this is the sort of thing automotive engineers think about constantly and debate among themselves. If you're like most drivers, you're lucky to know that turning the key makes the magic elves under the hood do their thing!
With the coming of more mainstream electric cars, the debate about the virtues of torque has been reignited. Diesel enthusiasts already preached the virtues of having lots of twisting force at low RPMs, which can be a huge advantage. While that certainly can help in different situations, loads of low-end torque isn't everything.Â
If you see a car's dyno results, you'll notice the torque and horsepower curves intersect at a certain point. Despite popular legend, that's not always at the same point. If you look at the results for an electric vehicle, diesel truck and gasoline car, those torque and horsepower curves will look quite different from one to the next. In other words, torque is related to horsepower and has a big impact on performance.Â
Are you thoroughly confused or do you have this all wrapped up in your mind? Take the quiz now and test your knowledge!Â
What is torque?
another measurement of horsepower
the electrical output of an engine
force that causes an object to rotate
It might be one of the most misunderstood specs on a car, but torque really is just a measurement of force that causes an object to rotate. If you're not familiar with how cars work, that might leave you wondering what torque has to do with vehicles.
how quickly the pistons go up and down
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What's a common tool used to apply a specific amount of torque to something like a bolt?
torque wrench
A torque wrench is like a socket wrench, only you can dial in a specific torque setting, using a special mechanism at the end.
torque meter
socket wrench
needle nose pliers
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When talking about torque, what does Nm stand for?
nothing much
nano meter
non-meter
newton meter
In countries where the International System of Units is used, people talk about how many Nm of torque a car produces, or how many Nm of torque you need to apply to a specific bolt.
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What does high amounts of torque do to help when towing?
makes you hit a higher top speed
means you don't slow down at all
It reduces stress on the vehicle.
If an engine produces loads of low-end torque, you don't put nearly as much stress on the engine, drivetrain, etc. as you tow especially heavy loads.
makes going downhill much safer
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What is a torque curve?
plotting on a graph showing torque output at different RPMs
When measuring the torque output of a car, a dyno will show the torque curve, or just how much lb.-ft. of torque is produced at every RPM. You'll notice the result is a curving line, at least for most vehicles.
how the driveshaft curves when torque increases
when the car veers left under hard acceleration
a special kind of pitch in baseball
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How is torque related to work?
It isn't.
They're the same thing.
1 lb.-ft. of torque equals .5 units of work.
Any rotation qualifies as work.
In physics, work is when a force moves an object. When talking about torque, the work is how much an object rotates through an angle.
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Why can you apply greater torque with a socket wrench breaker bar?
magic
It has a bigger head.
The longer handle makes this possible.
Breaker bars typically have longer handles than other types of socket wrenches, which means you're using a longer lever. Of course, you also need the space necessary to use that lever, which is always a consideration you need to make.
The grip is stickier.
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With electric vehicles, when do they usually produce peak torque output?
about 1,200 rpm
off the line
If you haven't driven an EV before, the feeling of having full torque delivery from a standstill is pretty invigorating, and a little weird.
at about 30 mph
at around 2,300 rpm
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How do turbochargers usually affect torque?
They do nothing.
They provide a boost at mid- to high-level RPMs.
It really depends on the turbo system, but most don't add extra horsepower and torque until the middle to higher end of the rpm range, thanks to the turbine(s) needing to spool up.
They add just a little bit more.
They will double output.
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Why do some automakers purposely understate the torque rating for a vehicle?
They're inherently liars.
for better fuel economy ratings
to trick insurance companies
There are many reasons.
Automakers will understate not only torque but also horsepower produced by some cars, sometimes to appease safety advocates, keep the cars under the radar from non-enthusiasts, or sometimes because of politics in the companies.
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When you see a torque rating listed for a car, what percentage of the total output does it represent?
50 percent
80 percent
90 percent
the maximum
You probably see torque and horsepower ratings all the time, which are the peak or maximum output for a car.
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What is the difference between lb.-ft. and ft.-lb. torque ratings?
The first is correct.
The second is correct.
One measures torque and the other electrical output.
nothing
Some people write or say lb.-ft. and some prefer ft.-lb. It doesn't really matter which a person uses, because the rating is the same.
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Where does torque originate in an engine?
camshafts
the crankshaft
The crankshaft translates the up-and-down movements of the pistons into spinning or twisting, so it's the originator of torque for a car, which then is passed through the drivetrain.
pistons
valves
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What is the equation for torque?
T = F*sin(r)
T = F+R
T = F*r*sin(theta)
If you for any reason need to calculate torque and you don't have a machine to do it for you, this equation can come in handy.
T = 3.45965*7
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When all torques acting on an object total up to zero, what is the result?
rotational equilibrium
The net torque is all the different forces acting on an object's rotation. Rotational equilibrium means there's no net torque being applied to an object, so it doesn't spin.
the Earth explodes
atoms split
your bolt strips out
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Why do diesel engines typically make so much more torque?
several reasons
Thanks to diesel fuel packing more energy per drop, diesel engines running at a higher compression ratio, and diesels often using a ton of turbo boost, they can whip out monstrous amounts of torque.
magic
Diesel engines are sealed better.
Diesels have larger crankshafts.
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How does a Roots supercharger impact torque production for an engine?
It boosts low-end torque.
The way a Roots supercharger is designed, it runs off the engine's belt, which means you get immediate power delivery for great low-end torque.
It makes better high-end torque.
It only benefits torque in the middle of the rpm range.
It provides no benefit.
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What is torque loss at the wheels?
a myth
when the wheels slip on ice
the difference in what the engine makes and what turns the wheels
Quite a few factors affect the loss of torque produced by the engine and what makes it all the way to the car's drive wheels, something engineers are always trying to improve through various designs.
something only experienced by AWD cars
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Why do automakers provide torque specs for bolts on vehicles?
They're too paranoid.
So everything stays together correctly.
If a bolt isn't tightened to spec, the vehicle can experience a number of difficulties, such as a loss in engine compression, suspension parts separating under load, etc.
It's a guideline for mechanics only.
as a way to make extra money
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What does torque do for off-the-line acceleration?
It helps greatly.
If your car has excellent low-end torque, you can jump off a starting line quickly. That doesn't necessarily mean you'll win a race, just that you'll have a good start.
It helps a little.
It can hurt it.
absolutely nothing
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Why does torque in an engine peak before horsepower?
It's a mystery.
pure magic
losses in volumetric efficiency
Thanks to the nature of how engines produce torque, the output peaks earlier because valves and other mechanicals in an engine lose efficiency and airflow slows, resulting in volumetric efficiency losses.
Torque has nothing to do with horsepower.
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What does using nitrous oxide do for torque?
It can result in a dramatic increase.
As probably anyone would suspect, torque can rise dramatically with nitrous fogged or injected into an engine, because it allows the engine to burn more fuel, resulting in more work done.
nothing
It reduces torque output.
at least triples output
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What could happen if you only put 30 lb.-ft. of torque on lug nuts that need 50 lb.-ft. of torque?
Your fuel economy improves.
You could accelerate faster.
The brakes could heat up sooner.
The wheels could come off the car.
There's a reason why automakers provide torque specs even for the lug nuts on your car, because it ensures the wheels are on tightly, without causing damage to any parts.
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How do you measure the torque output of a car's engine?
You can't.
with a dynamometer
A chassis dyno is a type of machine with rollers and other instruments designed to measure the torque and horsepower produced by your car.
with a screwdriver
with a socket wrench
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What's the general relationship between torque and displacement?
There isn't one.
The more of one, the more of the other.
Because big engines with plenty of displacement have bigger components, they can really get the crankshaft spinning, producing more torque. Of course, forced induction can help a smaller engine churn out a surprising amount of torque.
Lots of displacement equals less torque.
More torque lowers displacement slightly.
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If you want to tow heavy objects with a vehicle, where do you want the peak torque to be?
above 6,000 rpm
in the middle of the rpm range
at the lower end of the rpm range
The hardest part for an engine and drivetrain when it comes to towing is getting that extra weight moving, which is why have low-end torque in abundance is a good thing.
It doesn't really matter.
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Why does torque output fall between the crankshaft and the drive wheels of a car?
nobody knows
mechanical losses
Because the torque made by the engine must be sent through different components, there's a chance for some of that force to be lost, which is why measuring torque at the wheels is important.
temperature changes in the air
the nature of gasoline
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How would a centrifugal supercharger affect torque output?
It provides plenty of low-end torque.
It lowers it significantly.
It has zero effect.
It increases torque higher in the rpm range.
Because centrifugal superchargers have a design that's somewhat similar to a turbocharger, they don't provide the low-end torque boost you get from a Roots supercharger.
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What does high levels of torque mean for city driving?
The car is harder to control.
You'll have horrible fuel economy.
You can get the car moving again with ease after stopping.
Torque is what you feel really launch a car from a standstill. Considering you stop a lot in the city, having lots of torque will help you get back up to speed easier after pausing for lights, pedestrians, etc.
The car will be really slow.
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What kind of torque curve do race cars have?
low-end peak
mid-range peak
high-end peak
It depends on the setup.
Motorsports teams tune their cars for the nature of each competition, which includes altering a car's torque and horsepower curves. If there's a small track with plenty of tight turns, plenty of low-end torque could be good for accelerating quickly after slowing, while high-end horsepower is good for long straightaways.
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As electric cars accelerate, what happens to their torque output?
It stays the same.
It goes up and down.
It keeps increasing.
It falls dramatically.
Electric cars are unbelievably quick off the line, thanks to the peak torque output being available instantly, but that torque falls off quickly. As a result, EVs aren't great at longer races, like a mile-long drag race.
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How is torque related to horsepower?
Torque produced by the engine's crankshaft creates horsepower.
Without getting too technical, torque creates horsepower, because the faster an engine spins the more power it produces.
Horsepower generates more torque.
Torque slingshots horsepower to higher levels.
They're not related at all.
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Why do off-roaders love lots of low-end torque?
They like the sound.
It gives greater control on a trail.
You'll find that most off-roaders aren't the quickest vehicles, but they produce plenty of low-end torque, which allows them to power over obstacles without struggling as much, so they boast greater trail capabilities.
They don't realize what horsepower does.
They don't ever go on the freeway.
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With hybrids, how much torque do you get from a standstill?
about 200 lb.-ft.
around 70 percent of the peak amount
It depends on the electric motor.
Just like electric cars, hybrids boast instant torque delivery from a standstill, but their electric motors are typically smaller, so you won't enjoy quite the same rush.
about half of the total
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What must low-torque engines do to accelerate quickly?
use a supercharger
rev higher
Many high-revving engines produce little low-end torque. That means they're not the quickest off the line, but will make up for that in part by pouring on the horsepower at the top end of the rpm range.
be outfitted with corkscrew valves
They can't accelerate quickly.
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