I’ve borrowed a 2017 Volvo V90 Cross Country for an entire month, and will document my experience every week. This week I drove the V90 from my home in Durango, Colorado, up over Coal Bank Pass and Molas Pass to the tiny mountain hamlet of Silverton. It was a great test of both the heated seats and steering wheel, as well as the Volvo’s small, but powerful, engine.
I live in Colorado at 6,800 feet, or a bit more than 2,000 meters, above sea level. Living at this altitude means a few things: pasta and rice take a bit longer to cook because water boils around 200 degrees Fahrenheit or 93 degrees Celsius; visitors sometimes need some time to catch their breath after doing something as simple as walking up the stairs; and when you jump on the gas in most cars, there’s a lot less oomph than you’d find in that same car at sea level because there’s less oxygen in the air — and engines need oxygen to work.
cars can lose more than 20 percent of horsepower at 7,000 feet
According to a number of engineers I’ve spoken to, engines in most cars lose as much as 20 percent of their rated power simply by being at this high altitude. Cars without “forced induction” — engines that include superchargers or turbochargers that push extra air into the engine to create more power — lose around 3 percent of their horsepower per thousand feet in elevation. And, when I drive over a nearby mountain pass like Wolf Creek (10,852 feet) or Molas (10,910 feet), naturally aspirated engines (cars which let air into the engine naturally) lose more than 30 percent of their horsepower. And that’s something you notice when driving up a steep mountain pass.
But, by using forced induction in their engines, carmakers can “return” some of that lost power by using a super or turbocharger to force more air into the engine, increasing the amount of oxygen available to make tiny explosions and creating more horsepower. It’s something that a lot of carmakers have done to get more power out of smaller, more fuel-efficient engines. For example, Ford uses turbochargers in many of its newer engines, branding it as EcoBoost.