In recent years, hybrid fans and diesel advocates have been at each other’s throats, debating the merits and drawbacks of gas-electric versus diesel powertrains. But that debate for high-mpg bragging rights has mostly been theoretical. The diesel crowd could boast as much as they like about super efficiency, durability and zippy performance—but higher emissions kept the vehicles off dealership lots in California and other key states on the coasts. That’s all changed—because the Jetta TDI, available as a sedan and SportWagen, is finally making its national debut.
The diesel Jetta, now available in all 50 states, slips right behind the Toyota Prius and Honda Civic Hybrid to become the third most efficient vehicle in America. Official EPA numbers peg the manual 6-speed at 30 mpg in the city and 41 on the highway, and the automatic at 29 city and 40 highway. That’s a huge jump over the gas versions of the Jetta sedan and wagon, which are rated at 21/29.
The efficiency numbers are even more impressive when considering the Jetta’s TDI’s punchy performance. The vehicle uses a four-cylinder turbocharged, direct-injection system, proven in Europe and on race tracks in VW’s TDI cup. The Jetta TDI produces 140 horsepower and an impressive 235 pound-feet of torque.
The deal-closer for the green car buyer could be the availability of the Jetta TDI as a wagon. Hybrid buyers have been clamoring for a sedan with just a bit more room—but not a SUV. There have been rumors about a Prius wagon, but Toyota is notoriously tight-lipped about future releases. If you get tired of waiting for the first hybrid wagon, the Volkswagen Jetta Sportwagen may be singing your tune: “A wagon that gets 40 mpg on the highway!”
On top of this, super-greenies and energy security hawks can run biodiesel in the Jetta TDI. The Volkswagen warranty only allows a 5 percent blend of biodiesel, but for some, rules are made to be broken—especially when considering the stakes of continuing our national dependence on oil. Biodiesel offers a 100 percent petroleum-free alternative today. (We can’t tell you what to do; let your conscience be your guide.)
These opportunities are only possible because Volkswagen overcame the hurdle of California’s Tier 2, Bin 5 emissions standards. Unlike the Mercedes Bluetec system, which injects urea into the exhaust system to convert NOx to nitrogen and water, the Jetta uses a NOx storage catalyst, which holds the emissions in a reservoir until they can be burned off by the engine. In addition, the common rail fuel injection uses piezoelectric fuel injectors, which permits higher injection pressure than a mechanical system. These clean diesel technologies, developed in partnership with Audi and Mercedes Benz, are a breakthrough in terms of neutralizing emissions and filtering out diesel-related particulates.
Exciting stuff, but when looking at overall low emissions, diesels still can’t compete with hybrids. It’s a big milestone for a diesel to pass California’s Tier 2, Bin 5 standards, but that’s still only about average for a new vehicle. Meanwhile, the squeakiest of squeaky-clean standards is the SULEV, reserved for the Toyota Prius, Honda Civic Hybrid, and a handful of other vehicles including the conventional version of the Volkswagen Jetta.
Diesel-makers will be quick to point out that the difference between Tier 2, Bin 5 and SULEV is negligible—considering that both of these standards are many times cleaner than past generations of cars and trucks. That argument is supported by the federal government’s ruling the Jetta TDI as an “Advanced Lean Burn Technology Motor Vehicle.” Under the Energy Act of 2005, the Jetta TDI qualifies for a $1,300 federal income tax credit. If that money back from IRS softens the blow of paying 20 percent more for a diesel fuel, then clean diesel may at last be ready for prime time.
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