4 Cylinder vs. 6 Cylinder: Which is More Fuel Efficient?

Wondering about the difference in fuel efficiency of four-cylinder vs. six-cylinder engines? Here's what you need to know.

Nicole Wakelin | 

Mar 2, 2022 | 3 min read

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When it comes to fuel efficiency, what's the difference between four-cylinder vs. six-cylinder engines? There are several distinctions that can impact fuel efficiency. Understanding these differences can help inform you to make the best choice for your needs.

Understanding Cylinders

The cylinders in your engine are hollow metal tubes through which the pistons move up and down. As they move, the fuel and air mixture in the cylinders is compressed and creates a spark. This process happens very quickly with each cylinder moving in turn and creating the energy that moves your car. The cylinders are a critical component of your engine.

Four-Cylinder vs. Six-Cylinder

The obvious difference between the two is the number of cylinders, but there's a bit more to the story. The configuration of those cylinders also changes. An inline engine has the cylinders all in a row on one side of the crankshaft and is used for both four- and six-cylinder engines. There's also an H4 or "flat four", which puts two cylinders on either side of the crankshaft.

Since a row of six cylinders takes up a lot of space, many are instead situated in a V pattern. This is how you get a V6 engine. Larger engines, including eight-cylinder engines, use a V configuration, so they fit better in the engine compartment.

Which Is More Fuel-Efficient?

In most cases, you're going to get better fuel efficiency with a four-cylinder vs. six-cylinder engine. This is because they're smaller engines with less horsepower. The lower horsepower figures might be a negative for some, but if your focus is fuel economy, then it's a trade-off that's easy to make.

It's not all about horsepower, however. Remember, a four-cylinder is physically smaller. That means it weighs less. A car that weighs less is more fuel-efficient because it takes the engine less effort to move less weight. There's a secondary benefit to the reduced weight when it comes to performance.

Even though horsepower may be lower for a smaller engine, if the engine has to move less weight, then the lower horsepower number doesn't have as big of an impact on performance. Basically, a four-cylinder might have less horsepower, but its lower weight could help it have equal or better acceleration than something larger and heavier depending on the car.

While you might be able to accelerate in a compact car as quickly as a six-cylinder crossover, and with far better fuel efficiency, when it comes to hauling people in comfort, or passing other vehicles with ease on the highway, the larger more-powerful six-cylinder is often the better choice.

The Bonus of Turbocharging

Turbocharging an engine does two things: It improves overall performance, and it improves fuel economy, depending on how you drive. The better performance helps make up for being smaller than a six-cylinder engine. In fact, it's possible that a turbocharged four-cylinder will perform just as well as a non-turbocharged six-cylinder engine.

A turbocharged engine works by forcing more air into the internal combustion process. This lets more of the fuel power your car rather than being wasted as exhaust gas. It's enough to make the engine run more efficiently so you get better fuel economy.

Generally, a four-cylinder engine offers better fuel economy than a six-cylinder. Its better fuel economy is mostly due to having less horsepower but also by being smaller and reducing the weight of your car. Add in turbocharging, and there's even more improvement in fuel efficiency and performance. If fuel efficiency is a priority and you want to make fewer stops at your local gas station, then looking for a car with a four-cylinder engine is a good strategy.

Nicole Wakelin

I write about cars. A lot. That's because I’ve always loved cars and the fact that they regularly hand me the keys to shiny new automobiles so I can write about them is a constant source of amazement. I cover breaking news, write reviews, and attend auto shows and new vehicle launches across the country. The more winding the road and the more unknown the route, the better.