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Clearly it will take time to find a following like VW has developed over decades in the U.S. But as far as the engine itself is concerned, the GM 2.0L turbodiesel is a strong start.
Ward’s 10 Best Engines competition has recognized outstanding powertrain development for 20 years. This installment of the 2014 Behind the 10 Best Engines series looks at development of GM’s first U.S. passenger-car diesel in 25 years.
When a team of GM Powertrain engineers set out to modify a tried-and-true GM of Europe turbodiesel I-4 for U.S. Chevrolet Cruze compacts, it had a clear target in mind: theJetta TDI 2.0L diesel.
When they were done, says assistant chief engineer Mike Siegrist, they felt they had beaten VW's excellent 4-cyl. in almost every way.
"I believe we have a superior product," he says. "It's powerful, efficient and clean, and it will change perceptions of what a diesel car can be."
It certainly made WardsAuto editors believers. The more time they spent in the car, the more they liked it.
"This is an excellent diesel engine," said one editor. "It stands toe-to-toe with the best from Germany."
The 2.0L Cruze turbodiesel pumps out 151 hp and 264 lb.-ft. (358 Nm) of torque at just 2,000 rpm, compared with the current ’14 Jetta's 140 ponies and 236 lb.-ft. (320 Nm). Plus, it offers an overboost feature that bumps torque to 280 lb.-ft. (380 Nm) for up to 10 seconds of grin-inducing (or 2-lane passing) extra thrust.
The Jetta TDI with its available automatic transmission beats the Cruze turbodiesel automatic (no manual offered) with 30 mpg (7.8 L/100 km) vs. 27 mpg (8.7 L/100 km) in the city and 34 mpg (6.9 L/100 km) vs. 33 mpg 7.1 L/100 km) in combined ratings.
But the Chevy tops the Jetta's highway rating with 46 mpg (5.1 L/100 km) compared with 42 mpg (5.6 L/100 km), contributing – along with a relatively large fuel tank – to a best-in-class 700-plus mile (1,127 km) highway range.
WardAuto editors logged an average 36.5 mpg (6.4 L/100 km) in 446 miles (718 km) of mixed driving with their test Cruze diesel and 46.7 mpg (5.0 L/100 km) on a 253-mile (407 km) highway trip, showing once again that diesels typically outperform their U.S. EPA ratings.
WardsAuto editors praised its torquey performance, though some criticized its low-speed noise, vibration and harshness characteristics. That is, until they found it compared well to much more expensive diesel luxury vehicles.
Interestingly, this 2.0L DOHC 16-valve I-4 diesel is a derivative of one used in European Opel Astras, Insignias and Zafiras, but not the same-size engine that powers Cruze diesel cars in other parts of the world. Why? Because the Opel engine was chosen as a better candidate for adaptation to North America.
"Forto introduce a diesel passenger car in the U.S. for the first time in 25 years," Siegrist says, "many engine and vehicle combinations were considered, and this one was picked as best suited for the American market. It had to make good torque, have great fuel economy and low emissions and be able to deal with U.S. OBD II diagnostics rules."
With a cast-iron cylinder block, forged-steel crankshaft, aluminum heads and (variable-swirl) intake manifold, the U.S. engine weighs a comparatively light 408 lbs. (185 kg).
Its dual camshafts are belt driven, and itscommon-rail fuel system uses Piezo injectors capable of multiple injections per cycle. The engine also features aluminum pistons that are oil-jet cooled, a variable-displacement oil pump for energy efficiency and an intercooled, variable-nozzle turbocharger mounted close to the engine for fast "light off" and quick throttle response.