BMW 3 Series Engines Through the Years: From Carburetors to Twin-Turbochargers

It’s no secret that the BMW 3 Series is a routine favorite among automotive enthusiasts and journalists, and part of that appeal is always thanks to the supple, high-performance engines at the heart of any 3 Series. With 36 years of engine development under its belt, BMW offered us a brief look back at the history of the 3 Series powertrain. Note, though, that not all of the engine varieties mentioned were sold in the U.S. market. So brush off your notebooks, and read on for a lesson on 3 Series history.

While it would later stake its claim to a series of inline-sixes, the 3 Series began life in 1975 with a compact inline-four engine. Of the four launch versions -- 316, 318, 320, and 320i -- only the top model had fuel injection. Offering a healthy 125 hp, the 320i sedan was subsequently crowned “world’s best sedan” in Europe.

But what’s automotive history without the addition of more power? By 1977, BMW had developed a new pair of inline-six engines, the 320/6 and range-topping 323i. The latter packed electronic ignition and 143 hp, but both engines were praised for their flexibility, smooth running characteristics, and surprising fuel economy. An entry-level four-cylinder also joined the fray in the late 1970s, in the 75-hp BMW 315.

When the second-generation 3 Series arrived in Europe in 1982, the base 316 boasted 90 hp from a carbureted four-cylinder engine. The two inline-sixes continued, with the hot 323i proffering 139 hp thanks to electronic fuel injection. In 1984 BMW launched the “eta” six-cylinder, a version of the engine with torque and fuel-economy at the forefront of its design goals. The 2.7-liter inline-six produced 122 hp, returned up to 28 mpg, had a catalytic converter, and boasted fully digital engine management.

The first diesel engine for the 3 Series arrived in 1985: the 324d boasted 86 hp and could cover almost 34 miles on a single gallon of diesel. Much more exciting, though, was the debut of the BMW M3, the first in a long line of high-performance variants of BMW products. A 2.3-liter inline-four engine provided 200 hp and went on to power a series of successful Touring Car racers in European championships.

More Valves, VANOS, and Diesel for the 1990s

A new generation of the vaunted 3 Series bowed in 1990, bringing with it engine improvements like dual-overhead camshaft designs and four-valve cylinder heads. BMW also brought its VANOS technology the 3 Series, allowing variable valve timing to improve power and economy. The generation’s top-rung engine was the 328i with an inline-six good for 193 hp. Two new turbodiesel sixes debuted, the 2.5-liter, 115-hp 325td, followed by the 325tds with 143 hp -- which ran from 0-to-60-mph in 10.4 seconds.

Later, BMW introduced direct injection on the fourth-generation 3 Series with the 320d, a four-cylinder diesel engine with performance credentials of 136 hp and a 128-mph top speed, yet economy of up to 41 mpg. For gasoline engines, BMW upgraded its valve-timing system to Double VANOS, allowing even better control of emissions and torque output. Among the applications was the new 330i, which packed a 3.0-liter inline-six good for 231 hp -- more than the first BMW M3. BMW claims it “set the new benchmark” for flexibility, reliability, performance, and efficiency.

Similarly, the 330d diesel received a rash of technical advancements: multivalve heads, direct injection, and a variable-turbine turbocharger, all of which conspired to produce 184 hp and a top speed of 141 mph. Even with the performance, it still returned 35 mpg.

In 2001, BMW launched Valvetronic, a system that eliminates a traditional throttle body and instead varies the opening of individual intake valves. It continues to be used on the majority of BMW engines (including Mini engines) today.

The fifth-generation 3 Series launched with three gasoline engines and one diesel: 320i, 325i, 330i, and 320d. The diesel scored common-rail injection and a variable-geometry turbocharger, helping power climb to 163 hp; the 320i four-cylinder offered 150 hp. Thanks to the addition of Valvetronic, output of the 330i shot up to 258 hp, and that of the 325i rose to 218 hp; a new magnesium-aluminum crankcase helped trim weight from the inline-six engines. The next big step in 3 Series engine advancement came with the 335i coupe, launched in 2007. Its 3.0-liter, twin-turbocharged engine was rated at 306 hp, and quickly spread to other models in BMW’s lineup.

Engines for the current 3 Series range from the tiny 115-hp 316d diesel and 143-hp 318i, to the twin-turbo 335i and the 4.0-liter V-8 in the go-fast M3. BMW maintains that its entire engine lineup offer engaging performance, while returning impressive fuel economy and a flexible, reliable driving experience. For the ultimate in efficiency, the special 320d EfficientDynamics can provide up to 57 mpg in European testing.

Now, who’s ready for a pop quiz on BMW engines?

Source: BMW

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