Definitions: 4-Cylinder Engine - Video
Pros: Superior fuel economy; affordable; new turbocharged 4-cylinder engine designs offer great power as well as miles per gallon
Cons: Modest acceleration (except turbo 4-cylinders); V6s are typically smoother and quieter
Summary: The 4-cylinder is a relatively small and simple engine, designed to maximize fuel economy while providing adequate power. These engines have had issues with noise and vibration, but they've improved by leaps and bounds in the past decade.
Not surprisingly, the 4-cylinder is the most popular engine type among today's top sellers, powering stalwart sedans such as the Ford Fusion and Nissan Altima, as well as crossovers such as the Honda CR-V and Toyota RAV4.
Until recently, it was standard practice for mainstream 4-cylinder vehicles to feature an optional, extra-cost V6. But with fuel economy taking center stage, many automakers have replaced those V6s with turbocharged 4-cylinders that make V6-like power but get more miles per gallon. Hyundai started this trend with the current Sonata; others have followed suit, including Chevrolet with the new Malibu.
What it means to you: For most car shoppers, a nonturbo 4-cylinder engine will be just fine. People consistently rank fuel economy as a higher priority than acceleration, and a regular 4-cylinder will certainly minimize the amount of fuel you use. Fortunately, most new 4-cylinder vehicles also have enough power to get out of their own way, which hasn't always been the case.