2015 Volkswagen Golf SportWagen 1.8T TSI 170 hp

The EA888 engine line is a state-of-the-art design that uses intelligent downsizing to deliver comparable power and torque to the outgoing engine, while at the same time improving efficiency substantially. This engine produces 170 horsepower at 4800 rpm, the same maximum output as the 2.5-liter unit it replaces, but its increased torque peak of 199 lb-ft (for automatic transmission models) occurs much lower in the power band. Because the broad swathe of torque starts at 1500 rpm—2750 rpm lower than in the previous engine—and lasts until 4750 rpm, the engine offers much better acceleration as well as helping to deliver better fuel economy and lower emissions than before.

2015 Volkswagen Golf SportWagen TDI

Augmenting the EA888's 16-valve, dual-overhead-camshaft layout is variable cam phasing on the intake side. The single-scroll IHI turbocharger feeds intercooled air through the aluminum-alloy crossflow head down into the cylinders, where it meets fuel delivered by a high-pressure direct-injection system.

At just 290 pounds, the new engine is also lighter than the five-cylinder unit, thanks to a combination of compact design, streamlined componentry, and a focus on lightweight materials. The cast-iron engine block uses a casting with a wall thickness of just 0.12 inches to reduce its weight to 72 pounds, while a lightweight polymer oilpan and aluminum-alloy screws and fasteners also trim mass. Other changes that help the engine shed pounds include a reduction from eight to four counterweights on the crankshaft and the use of smaller diameter main bearings.

2015 Volkswagen Golf SportWagen

The engine is also extremely compact, illustrated by the way in which the exhaust manifold has been integrated directly into the cylinder head. This not only improves the system coolant operation (aiding in rapid warm-up and improving efficiency) but also allows greater thermal management of the exhaust stream.