Turbochargers let automakers squeeze big-engine performance from smaller engines—but the technology comes with trade-offs.
For decades, bigger engines meant more power and effortless performance. Now automakers are proving that a much smaller turbo can deliver nearly the same punch—but there’s a trade-off.
Walk into an American dealership today and the engine bay may look very different from what it did 15 or 20 years ago. The familiar naturally aspirated V-6 or V-8 is increasingly being replaced by a smaller engine with a turbocharger.
A 2.0-liter turbocharged four-cylinder can produce the kind of power that once required a naturally aspirated V-6. Modern turbocharged six-cylinders can deliver performance that would have demanded a much larger engine in the past.
So why did automakers make the switch?
The basic idea is simple: reduce engine displacement, then use a turbocharger to force more air into the cylinders when extra power is needed.
A naturally aspirated engine relies on atmospheric pressure to fill its cylinders. A turbocharged engine uses exhaust gases to spin a turbine, which drives a compressor and pushes additional air into the engine.
More air allows the engine to burn more fuel and produce more power.
That gives manufacturers an attractive combination: a relatively small engine that can behave like a much larger one when the driver puts their foot down.
Automakers have been using this strategy for years. Ford's EcoBoost engines helped make turbocharging familiar to mainstream American buyers, while turbocharged four- and six-cylinder engines have become common across brands such as BMW, Mercedes-Benz, Hyundai, Kia and Volkswagen. Car and Driver has documented the broader shift toward turbocharging and engine downsizing across the industry.
There are several reasons.
A smaller engine can have lower pumping losses during light-load driving, while turbocharging allows manufacturers to recover much of the lost performance when acceleration is needed. Automakers also use smaller turbo engines as part of their efforts to meet increasingly demanding fuel-economy and emissions requirements. Consumer Reports has noted that this combination of smaller displacement and turbocharging is one reason the technology has spread so quickly.
There is also a packaging advantage. A compact four-cylinder can take up less space and weigh less than a large V-6 or V-8.
And from a marketing standpoint, the numbers look good.
A buyer sees a 2.0-liter turbo producing 250 or 300 horsepower and gets performance that would have seemed impressive from a much larger engine just a generation ago.
But horsepower is only part of the story.
A naturally aspirated engine is comparatively straightforward. A turbocharged powertrain adds a turbocharger, intercooler, additional plumbing, more sensors and more thermal stress.
That doesn't automatically make a turbo engine unreliable. Modern turbocharged engines can be extremely durable, and plenty of them have proven themselves in high-mileage service.
But there are simply more components involved.
Consumer Reports has found that some turbocharged engines have experienced reliability problems, including issues involving turbochargers and engine electronics. At the same time, its data also shows that many turbo engines perform well, meaning reliability is highly dependent on the specific powertrain rather than simply whether a vehicle has a turbo.
That distinction matters.
It would be misleading to say that every naturally aspirated engine will outlast every turbocharged engine. Engine design, maintenance, oil quality, operating temperatures, driving habits and manufacturing quality all play major roles.
This is where things get more complicated.
On paper, a small turbo engine can look like the perfect solution: use less displacement during normal driving, but make big-engine power when necessary.
In real-world driving, however, the advantage isn't guaranteed.
If the driver regularly uses the extra power, the engine has to produce more boost and burn more fuel. Hard acceleration, towing, steep grades and high-speed driving can erase much of the theoretical efficiency advantage.
Car and Driver tested hundreds of turbocharged and naturally aspirated vehicles and found that turbocharged vehicles were not inherently worse at matching their EPA highway fuel-economy figures. In its analysis, the average turbocharged vehicle actually exceeded its EPA highway rating slightly, while naturally aspirated vehicles roughly matched theirs.
In other words, the old assumption that "turbo equals worse real-world mpg" is too simplistic.
The same is true in the opposite direction: a turbocharged engine shouldn't automatically be considered more economical simply because it has fewer liters of displacement.
For many enthusiasts, the biggest loss isn't reliability or fuel economy.
It's character.
A naturally aspirated engine delivers power in a very linear way. Press the accelerator and the engine responds directly, with power building as the revs climb.
A turbocharged engine can produce a huge amount of low-end torque, but the response can feel different. Modern systems have reduced turbo lag dramatically, yet the character is still not identical to a large naturally aspirated engine.
That difference is especially noticeable in performance cars.
There's a reason enthusiasts continue to celebrate naturally aspirated engines such as the Chevrolet small-block V-8 and high-revving engines from Porsche, Ferrari and other manufacturers. Car and Driver has long noted that naturally aspirated engines are becoming increasingly rare outside a handful of performance applications.
The American market is unusual because large engines still have an important place in trucks, muscle cars and performance vehicles.
Turbocharging hasn't necessarily killed the V-8. Instead, it has changed where manufacturers choose to use it.
A turbocharged six-cylinder can now offer the torque and horsepower buyers once expected from a V-8, while a modern V-8 can be reserved for vehicles where sound, character and outright performance are part of the product.
That's why today's engine landscape isn't simply "turbo good, naturally aspirated bad" or the other way around.
It's a trade-off.
Turbocharging gives automakers a way to make smaller engines powerful, flexible and potentially efficient. Naturally aspirated engines offer mechanical simplicity, linear response and a distinctive driving character.
For the average driver, a modern turbocharged engine can be an excellent choice. For an enthusiast, the appeal of a larger naturally aspirated engine may have less to do with numbers on a spec sheet and more to do with how the car feels.
And as smaller turbo engines continue replacing larger engines across the market, that difference may become one of the things drivers appreciate most about the few naturally aspirated powertrains that remain.