Cars–big and small–are going turbo

EVEN with four cylinders, the Porsche Boxster promises greater levels of power.

THE PORSCHE Boxster is the latest vehicle to think small. It has swapped out its six-cylinder engine for a four-cylinder one. That’s not to say that it will be slower.

Porsche promises greater levels of power while still improving fuel-efficiency and emissions levels. The secret is the turbocharger.

A turbocharger is a compressor driven by the engine’s exhaust gases. It allows a small engine to take in greater amounts of air, to burn more fuel when needed, and to produce power levels similar to that of a much larger engine.

When full acceleration isn’t needed, the pressurized air is released, and the small engine burns less fuel.

Turbocharging has been widely used in performance applications, including the new Boxster. The new 718 Boxster’s 2-liter four-cylinder is good for 300 horsepower and 380 Newton-meters, while the 718 Boxster S delivers 350 HP and 419 Nm. That’s good for a zero to 100 kilometers per hour acceleration time of 4.7 seconds, and 4.2 seconds for the Boxster S. And yes, they are boxer engines.

Its stablemate, the 911 sports car, has had the Turbo model as its most powerful variant. And lately Porsche has added turbocharging to even the 911 “base” models, allowing them to produce even more power.

EcoBoost technology

Ford has been introducing its EcoBoost technology throughout its lineup, from the massive Expedition to the tiny Fiesta subcompact. No longer (at least relatively) are the days of the gas-guzzling Expedition as the new SUV carries a smaller twin-turbo V6 in place of the previous eight-cylinder.

The Focus hatchback and sedan, Explorer and Escape all have EcoBoost turbo engines as an option.

The most fun application may be in the Fiesta hatchback. The 1-liter, three-cylinder paired with the dual-clutch gearbox delivers a lot of smiles per hour, thanks to turbo technology.

Not just premium segment

The benefits of a turbo are no longer limited to the premium segment.

Chevrolet has introduced its Trax subcompact crossover with a 1.4-liter turbocharged engine. The turbo engine gives the Trax brisk acceleration, making it more fun to drive.

Subaru has long been associated with the turbo engine of its wild Impreza STI. Some loyalists were disappointed when the new Legacy sedan no longer carried a turbo engine.

Subaru does have the new Levorg sport wagon, which packs a turbocharged boxer four.

Widely anticipated is the new Honda Civic, which for the first time in its history has a factory turbo option. Here’s hoping that the sporty-looking Civic will pack the 1.5-liter, 158-HP turbo engine when it debuts in the Philippines.

Practically all modern diesel engines employ turbochargers. Relatively-small-displacement diesels are able to generate good amount of torque at low rpm levels, another benefit of turbocharging.

Turbo engines were known to be thirsty and prone to giving a delayed response. The delay was termed “turbo lag,” and was due to the turbocharger needing a second or two to spin its compressor before delivering the needed boost.

The lag has been mostly banished, thanks to new design. Variable-geometry turbochargers are able to deliver the needed boost even at low revs.

Some companies such as BMW have opted for twin turbochargers, the lower mass of the smaller turbos enabling quicker response. More advanced materials have allowed for lighter, more durable parts.

Sophisticated computer-controlled injection systems enable precise fuel delivery for better power and efficiency.

The turbo engine is one way that the internal combustion engine is eking out gains in performance and efficiency. No doubt they will be replaced one day by hydrogen fuel cells or electric motors, but here and now, the turbo is one fast way to go.