Engine Performance Quiz

Exhaust headers eliminate back pressure by giving each cylinder its own exhaust pipe.

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.

Engines tend to waste power during the exhaust stroke when they come up against the resistance of back pressure.

When nitrous oxide is heated, it splits into nitrogen and oxygen, making more oxygen available to the engine during combustion.

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.

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.

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.

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.

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.

Not all performance improvements boost horsepower or increase speed. Fuel economy is one such sign of a better-performing engine.

To become more powerful, the engine needs to be modified to accept more air and more fuel.

A supercharger improves a car's power output by about 50 percent.

A supercharger spins at at least 50,000 rpm.

Installing a supercharger is a fairly straightforward bolt-on procedure requiring basic tools.

An upgraded air filter improves airflow into the engine, allowing better combustion.

Air filters can easily be removed and washed to keep the engine's air clean.

Cold air is denser than warm air, so it can be mixed with more fuel.

Installing a performance chip is a simple plug-and-play project.

Most cars have computer chips that control engine function, and thus, engine power. Performance chips change the factory settings to improve power.

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.

Switching to lightweight alloy wheels can help improve performance as well as style.

Disc brakes are a popular upgrade, in part because they are lighter than drum brakes.

Drive line lash is the torque that's wasted as the engine shifts around.

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.

A cold air intake adds about 5 to 7 horsepower.

A cat-back exhaust has straighter pipes, which improve exhaust flow.

The catalytic converter can only be replaced when necessary.

Most car manufacturers actually advise against flushing modern engines, but it may help engines in older cars.

One source of poor performance is engine deposit buildup caused by old or dirty oil.