The One With The Six: The 2020 BMW M340i

The 2020 BMW M340i.

If you've ever wondered why the BMW 3-series sedan became a thing---it's the engine. Or it was. A silky-smooth inline six-cylinder, capable of propelling BMW's small (now mid-size) sedan quickly with seemingly endless reserves of both torque and horsepower. You would pin the speedometer, lose your license or both long before you ever felt you needed more from under the hood.

As technology has evolved and fuel economy has become a matter of law, automotive engineers have found that they can achieve that kind of power from a 2-liter turbocharged four-cylinder engine. And BMW has adopted them in the 330i. It's a fine engine---among the best of its type. But it doesn't have the same feel, the same sound as that glorious BMW straight six. If you want that in 2020---and can't quite justify the leap to the hardcore twin-turbo 425-horsepower M3, you want the BMW M340i.