Volkswagen AG's 2.0L SOHC I-4 Turbodiesel: Affordable Diesel

The last time an affordable diesel landed on the Ward's 10 Best Engines list, in 1997, a gallon of regular unleaded cost less than $1.25 and Americans were discovering the functionality of gas-guzzling SUVs and personal-use pickups.

At the time, diesels were as relevant as hybrids, which hadn't even arrived yet in the U.S. True, VW diesels of the day were capable of 45 mpg (5.2 L/100 km) when the Toyota Prius was just starting production in Japan.

But consumers cared little about fuel economy, and that VW turbodiesel belched smoke during startup, although it was deliciously torquey.

Today, a modern, high-pressure common-rail European turbodiesel from VW sets a new standard with the all-new 2.0L SOHC I-4 that wins a 10 Best Engines award in its first year of eligibility.

The spunky-yet-quiet I-4 breaks new ground by meeting the strict emissions standard without expensive (and inconvenient) urea-injection aftertreatment, necessary for larger diesels. Instead, oxidation catalysts and regenerating particulate filters do the job, allowing the all-new Jetta TDI to be sold in all 50 states. “Any engine that delivers 36 mpg with such great drivability and affordability deserves to be 10 Best,” says one judge.

Engine type: 2.0L turbocharged SOHC I-4 diesel

Displacement (cc): 1,968

Block/head material: cast iron/aluminum

Bore × stroke (mm): 81 × 95.5

Horsepower (SAE net): 140 @ 4,000 rpm

Torque: 236 lb.-ft. (320 Nm) @ 1,700 — 2,500 rpm

Specific output: 70 hp/L

Compression ratio: 16.5:1

Assembly site: Salzgitter, Germany

Application tested: Jetta TDI sedan

EPA city/highway (mpg): 29/40