Efficient engine performance is a feat of precision engineering. Having the proper ratio of all required elements is part of the equation, but there are outside variables which can have a pronounced effect if not regulated by more modern technology. Manufacturers cannot always control for things like climate and altitude, but they still impact performance. So other measures must be put in place that can act quickly to correct and keep cars reliable no matter where they may travel.
The Perfect Cocktail
Gasoline-powered combustion engines require a precise mixture of air, fuel and spark to run efficiently. If the input of one changes, the other elements must accommodate and adjust or the engine will run rich (overuse of fuel) or lean (too much air, not enough power), depending. Fuel is only slightly affected by environment, but air quality varies quite a bit. Modern engines have advanced sensor-controlled systems that constantly monitor the mixture and can adjust quickly, but this hasn’t always been the case. And even a driver of a more recent model might notice a difference in handling between the desert plains and driving high in the Rockies.
Turned Up (or Way Down)
Climate affects performance in a number of ways, mostly through temperature. An extremely cold ambient temperature thickens oil and makes it more difficult for the battery to muster up the amps necessary to turn an engine over. The thickened oil doesn’t help — in fact, it creates a bigger job at startup with less energy, and anyone who’s passed a cruel northern winter knows this struggle. In the other direction, extreme heat puts your engine that much closer to overheating, and your cooling system must be on its best game to keep up.
One of the more surprising outside factors that influence engine performance, is altitude. As you rise above sea level, air density decreases, meaning there’s less oxygen in the mix on the intake. Furthermore, the air pressure decreases with altitude, so less air generally makes it into the cylinder. This will cause an engine to run rich and/or lose power. Modern air and fuel delivery systems are designed to help compensate for changes in air density, as are forced induction add-ons such as turbo and superchargers. Older vehicles using carburetors did not have this capability and metered fuel without regard to the waning oxygen, flooding and stalling the engine on steep ascents.
Ultimately, engine performance is far less of a fair weather friend than it used to be. Customers need to know that they can rely on their cars no matter where they may live, and manufacturers have responded with technology that takes into account the challenges posed by any height or temperature. But it’s important to keep in mind that engines are designed to operate under very specific conditions, so if you feel like you’re losing power in the cold or up high, rest assured you aren’t crazy.
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Blair Lampe is a New York-based professional mechanic, blogger, theater technician, and speechwriter. In her downtime she enjoys backpacking wherever her boots will carry her, rock climbing, experimental theatre, a crisp rosé , and showering love on her 2001 Sierra truck.