Lackluster fuel economy from five- and six-cylinder engines in the 2012 Volkswagen Passat is neatly counterbalanced by the overachieving turbodiesel TDI.
In the base 170-horsepower, five-cylinder Passat, a low curb weight and a long top gear work together in manual-transmission models to register an estimated 21/32 mpg rating. The Environmental Protection Agency (EPA) hasn't confirmed those numbers yet, but VW says the estimates are in line with the agency's normal process. The same testing on the five-cylinder automatic-equipped sedan yields a prediction of 22/31 mpg.
For the upcoming Passat VR6, VW pegs fuel economy at 20/28 mpg -- one rating, since that version will only be outfitted with a six-speed automatic.
Regardless of which transmission is chosen--the five-speed manual, or a six-speed dual-clutch automatic without shift paddles--the Passat TDI checks in with an estimated rating of 31/43 mpg. Volkswagen says that makes the four-door the most fuel-efficient mid-size vehicle offered for sale in the U.S. In other model lines, the TDI has accounted for up to 25 percent of all sales, too, where hybrid models often only add up to 5 percent of total volume projections.
Diesel geeks will be interested to see the Passat TDI gets better fuel-economy numbers than the smaller, lighter Jetta TDI. In this case, VW says it's because it uses a urea-spray after-treatment on emissions, which allows it to operate the same engine more efficiently in the larger car. The smaller Jetta's nearly identical turbodiesel goes without the urea treatment, while still keeping its nitrogen-oxide emissions below newer, stricter limits.