Engine Performance Quiz

Estimated Completion Time
3 min
Bolt-on accessories that make it easier for your engine to push exhaust gases out of the cylinders are called:
headers
Headers improve engine performance by making the exhaust stroke less power intensive.
footers
mufflers

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If you're using an exhaust header with a four-cylinder engine, how many exhaust pipes will you have?
one
two
four
Exhaust headers eliminate back pressure by giving each cylinder its own exhaust pipe.

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Why do properly inflated tires improve fuel efficiency?
they decrease the force of friction
Since well-inflated tires have less contact with the road, they encounter less friction and the engine doesn't have to work as hard to move the car.
they counteract the force of gravity
they're lighter

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During the exhaust stroke, many engines lose power through:
exhaust manifolds
back pressure
Engines tend to waste power during the exhaust stroke when they come up against the resistance of back pressure.
exhaust headers

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Nitrous oxide improves engine performance by providing more what?
nitrogen
oxygen
When nitrous oxide is heated, it splits into nitrogen and oxygen, making more oxygen available to the engine during combustion.
hydrogen

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What other benefits does nitrous oxide provide?
a cleaner-burning fuel
a cooling effect
When it vaporizes, nitrous oxide provides a cooling effect on the intake air, which increases the air's density and provides even more oxygen inside the cylinder.
a quieter performance

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Why do cars normally carry only a few minutes worth of nitrous oxide?
it's difficult to find
it's expensive
it's fairly bulky
Due to the bulk of nitrous oxide, it takes up a significant amount of space even when compressed into a liquid. Drivers tend to carry only a small amount and use it selectively by pushing a button.

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How much faster can the turbine in a turbocharger spin when compared to a regular car engine?
10 times faster
20 times faster
30 times faster
Using the exhaust flow from the engine, turbines in a turbocharger can spin the air about 30 times faster than a regular car engine can -- at speeds of up to 150,000 rpm.

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How many valves per cylinder do dual overhead camshafts typically have?
just two
at least four
Dual overhead camshafts (DOHC) produce more power and can run at higher speeds since they allow an engine to have at least four valves per cylinder.
six or more

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Three fundamental causes can keep your engine from running. Which of the following is not one of them?
bad fuel
lack of compression
worn-out ball bearings
Although thousands of minor things can create engine problems, the big three include a bad fuel mix, a lack of compression and a lack of spark.

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Which of the following is considered an improvement in engine performance?
better fuel economy
Not all performance improvements boost horsepower or increase speed. Fuel economy is one such sign of a better-performing engine.
louder exhaust sounds
more impressive revving noises

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What does the engine need to go faster?
more nitrous oxide and a better turbocharger
less air and more fuel
more air and more fuel
To become more powerful, the engine needs to be modified to accept more air and more fuel.

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How much power does a supercharger add?
25 percent more
50 percent more
A supercharger improves a car’s power output by about 50 percent.
200 more horsepower

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How fast does a supercharger spin on its own?
25,000 rpm
50,000 rpm
A supercharger spins at at least 50,000 rpm.
150,000 rpm

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Which of the following projects can be a DIY job for a beginner?
installing a supercharger
Installing a supercharger is a fairly straightforward bolt-on procedure requiring basic tools.
machining the valves
performing a drivetrain swap

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How does an air filter improve performance?
It heats the air.
It adds special chemicals to the air.
It improves air flow.
An upgraded air filter improves airflow into the engine, allowing better combustion.

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Which of the following aftermarket performance parts are designed to be washable and reusable?
bearings
air filters
Air filters can easily be removed and washed to keep the engine’s air clean.
nitrous injectors

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How does a cold air intake kit improve performance?
It improves the air-fuel mixture.
Cold air is denser than warm air, so it can be mixed with more fuel.
It helps the engine spin faster.
It takes pressure off the radiator.

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Which of the following projects is the easiest?
installing a turbocharger
installing a hood scoop
installing a performance chip
Installing a performance chip is a simple plug-and-play project.

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What does a performance chip do?
adds more memory to the car’s computer
helps the engine run without as much gas
alters the engine programming in the car’s computer
Most cars have computer chips that control engine function, and thus, engine power. Performance chips change the factory settings to improve power.

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What’s a free way to improve a car’s performance?
take out the headliner and interior door panels to save weight
Weight reduction can be as simple and inexpensive as removing unnecessary parts, such as upholstery and trim, but it’s only recommended for drivers who don’t really care about comfort.
make a spoiler out of junkyard scraps
trade your car for someone else’s

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Which of the following parts are easy to swap for lighter-weight alternatives?
subframe
transmission
wheels
Switching to lightweight alloy wheels can help improve performance as well as style.

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Which of the following statements is true?
Glass windows are lighter than acrylic windows.
Disc brakes are lighter than drum brakes.
Disc brakes are a popular upgrade, in part because they are lighter than drum brakes.
Original body panels are lighter than carbon fiber body panels.

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What is drive line lash?
hitting the gas so hard that the driveshaft cracks
hitting the gas so hard that your head snaps back
wasted torque from natural engine movement
Drive line lash is the torque that’s wasted as the engine shifts around.

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How can drive line lash be improved?
Install firmer motor mounts.
Most factory motor mounts are soft, which increases ride comfort but also wastes some of the engine’s energy. Performance motor mounts, which are firmer, help reduce wasted torque.
Install softer motor mounts.
Install racing harnesses.

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How much horsepower does a cold air intake add?
10 percent
25 to 50 horsepower
5 to 7 horsepower
A cold air intake adds about 5 to 7 horsepower.

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How does a cat-back exhaust improve performance?
The pipes are curved.
The pipes are straighter.
A cat-back exhaust has straighter pipes, which improve exhaust flow.
The pipes are insulated with cat fur.

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One car part is notable for its strict environmental regulations, meaning that it’s illegal to replace it unless it’s broken. Which part?
the tires
the catalytic converter
The catalytic converter can only be replaced when necessary.

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True or false: an engine flush is recommended to improve performance.
false, always
true, always
true, in older cars
Most car manufacturers actually advise against flushing modern engines, but it may help engines in older cars.

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What might cause a car to run at less-than-factory performance?
a buildup of crud on the engine
One source of poor performance is engine deposit buildup caused by old or dirty oil.
a radio that was removed to save weight
the perfect mix of air and fuel

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You Got:
/30
Reid Neubert/Photolibrary/Getty Images
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