GM’s last efforts to put diesel engines in U.S.-market passenger cars in the 1980s were famously—or rather, infamously—half-baked, and turned a generation of American consumers against oil-burners. But in Chevrolet’s new Cruze diesel, which is making its debut at the 2013 Chicago auto show, GM probably doesn’t have to worry about its prior bad-diesel acts. Compression-ignition engines have been gaining mainstream popularity here in the U.S., largely due to their high fuel-economy numbers. That the Cruze diesel is pretty far removed from a smoky ’86 Chevette bodes well, too.
Chevrolet's turbo-diesel four-cylinder was conceived in Torino, Italy, and is created in Kaiserslautern, Germany, but it has been educated in the U.S. It's not a new engine, being already used in Opel Astras and various other GM vehicles around the world at a rate of 400,000 annually. Still, the U.S. version is unique, thanks to the varied driving conditions found in North America: 120-degree Fahrenheit Death Valley summer heat, minus-40-degree northern-Minnesota winters, and 14,000-foot Colorado mountain passes. And U.S. emissions rules require more tweaks, such as higher levels of exhaust-gas recirculation, and different exhaust after-treatment hardware.
Chevy engineers opted for a system essentially downsized from the Duramax pickup diesel engines, using a particulate filter plus urea injection to trim oxides of nitrogen. The 4.5-gallon urea tank is located under the trunk floor where the spare tire used to live (Chevy supplies a can of fix-a-flat instead). In normal driving, a tankful of urea should last 10,000 miles—topping off the urea is recommended when the Cruze gets its scheduled oil changes every 7500 miles.
The foundation of the Cruze diesel is the Euro-standard iron-block, aluminum-head four-cylinder with a steel crankshaft and aluminum pistons with a compression ratio of 16.5:1. The diesel juice is piped in at just over 23,000 psi via the common fuel rail and piezo injectors. Although torque peaks at 264 lb-ft at 2600 rpm, 250 lb-ft is available from 1750 to 3000 rpm, and a boot on the pedal brings 280 lb-ft of overboost for up to 10 seconds—the diesel version of IndyCar's “push to pass.” A six-speed automatic is the only available transmission.
The sharp-eyed might notice the 17-inch aluminum wheels and low-rolling-resistance tires, but there's not much to visually set the diesel apart from other Cruzes. Tough to see are aero bits, mostly picked up from the Cruze Eco, such as the grille opening and shutters, underbody aero panels, and new engine-compartment baffling. The heaviest nondiesel Cruze LTZ we’ve weighed comes in at 3208 pounds, and the 300-or-so-pound additional heft of the diesel kicks it to an estimated 3500 pounds, which calls for other changes, slightly bigger brakes being one. There's added sound isolation, such as a different dash mat and hood blanket that help keep diesel rattle from reaching the cabin, Other than which pump you use at a fuel station and the diesel noise that almost disappears once you're in the car, the Cruze diesel’s performance envelope is virtually identical to that of the 1.4-liter gas-turbo version. The diesel’s estimated 0-to-60 time of 8.1 seconds puts it nose to nose with the gas-turbo Cruze, although the diesel’s torque feels much richer at part throttle and very solid in the 0-to-40-mph range.
We drove one to Indy and back for the 500. On the 292 miles south, we stayed with traffic, much of it at 70 to 80 mph, and our average with a few stops, including the Auburn Cord Duesenberg Automobile Museum in Auburn, Indiana, was an indicated 44.9 mpg. Heading back to Detroit on the freeway, we once again began monitoring estimated fuel economy with the car’s trip computer. During the first 40-mile stretch at a boring 55 mph, we saw a Prius-like 58.4 mpg, followed by another 30 miles at 65 mph for a still-impressive 53.9 mpg, and a more satisfying 20 miles at 75 mph and 43.4 mpg. A 30-mile off-freeways-through-towns stretch brought 43.1 mpg.
A more scientific evaluation of the Cruze diesel’s fuel economy will be accomplished in an upcoming road test, but the Chevy appears to be playing in the same sandbox as is its major competitor, the Volkswagen Jetta TDI. Consider EPA window-label fuel economy: the Cruze diesel at 27 city/46 highway, the Jetta TDI at 30 city/42 highway. Multiply the EPA highway number by fuel-tank size, and the potential range shakes out to the Cruze at 717 miles, the VW at 609 miles. At 151 horsepower, the Cruze edges out the Jetta’s 140-horse rating. Torque is a similar story, with the Cruze at 264 lb-ft, the VW at 236. Warranty: The Cruze gets five years/100,000 miles; the VW is five years/60,000 miles. Pricing is another head-to-head battle with the Cruze at $25,695 and VW TDIs with the DSG automatic starting at $24,885 (Jetta), $25,390 (Beetle), and $26,130 (Golf).
Even so, diesel fuel is as expensive as premium unleaded in many areas, and as nicely appointed as it is, the Cruze diesel’s $25,695 base price is a couple thousand dollars more than the top-trimmed Cruze LTZ gas-turbo automatic's. So it could take a sharp pencil and a bunch of miles for the fuel-cost savings of the diesel to offset its higher initial cost compared with the 26 city/38 highway LTZ gas-turbo automatic. But then again, the new turbo-diesel takes the Cruze driving experience to new heights, with generous part-throttle torque and the ability to climb grades or accelerate without a lot of transmission downshifting. The days of slow, smelly, smoky diesels are indeed behind .
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