Diesel: Come On, Detroit

We've been writing about new-generation diesels for a few years now — yet the only modern diesels we can test are in heavy-duty pickups. I don't breed horses, so I don't have much need for the Power Stroke's 560 lb.-ft. (759 Nm) of torque.

We also tested General Motors Corp.'s 6.6L Duramax (Best Engines winner in 2001 and 2002) and the all-new 5.9L Cummins Engine Co.-made turbodiesel in Dodge's Ram HD. The Power Stroke was the best, but only because we met a guy at a gas station who said the secret to minimizing the pavement-cracking rumble at startup was to cycle the glowplugs three times before starting the engine. It worked.

The High Output Cummins is impressive, but its current emissions profile disqualifies it for sale in California and two other states. Moreover, Chrysler hasn't yet engineered an automatic transmission for the Cummins.

Come on, Detroit. Is this the best you can do? We had to put the touch on one of your loyal suppliers, Robert Bosch Corp., for a few European-spec diesel-powered cars. Bosch obliged, offering up a BMW 530d, Jeep Grand Cherokee 2.7 CRD and Volvo S80D5.

Combined fuel economy for each car is between 30% and 62% better than its gasoline equivalent, and the torque far outstrips each car's best gasoline engine.

Some judges grumbled the diesels weren't always quiet, especially at startup, but overall the impressions were favorable. A number of editors agreed the BMW may be the finest showcase yet for modern direct injection/common rail turbodiesel technology.

“I sort of chased a boisterous Trans Am from light to light the other day, and the BMW had no problem 0-70 mph,” writes one staffer after driving the BMW 530d.

Editor Drew Winter says the 2.4L all-new all-aluminum turbodiesel in the Volvo S80 felt like a big V-6 on the highway.

The Grand Cherokee also gets an impressive kick from the lavish Mercedes-made 2.7L CRD Power Tech diesel — so much so that Jeep drivers would never miss the standard 4L gasoline I-6. The 4L has more horsepower, but the smaller diesel presents 77 lb.-ft. (104 Nm) more torque. We look forward to testing the CRD in the Jeep Liberty next year (see p.13).

I know it's risky to bring diesel cars to the U.S. Most new diesels, in their current state of technical development, won't meet lurking emissions standards.

OK, sell diesels for a few years — and win so many converts the market forces legislators to soften up on near-term emissions.