Volkswagen will offer new TDI diesel engine

By Kelsey Mays and Fred Meier | Cars.com and USA TODAY

Volkswagen will offer a new, more efficient four-cylinder diesel engine in its 2015 Golf, Beetle, Passat and Jetta that it says could be EPA-rated as high as 46 mpg highway when the final numbers are in.

VW said the new diesel four (the EA288 in its nomenclature) will replace its ubiquitous 2-liter turbodiesel four.

In its announcement, VW noted that it's sold more than 47,000 diesel cars in the U.S. so far this year -- about a fourth of VW sales, and more than three-fourths of all diesel light vehicle sales here.

The engine is similar to the current diesel — turbocharging, direct injection, the same bore and likely the same 2-liter displacement, spokesman Mark Gillies told Cars.com.

But beyond that, VW says it is a new design with new features that include better exhaust-gas treatment, friction reduction and an intercooler integrated with the intake manifold. If that's all Greek to you, VW says the results should be better fuel mileage, sharper accelerator response and lower emissions.

The new diesels also have slightly more oomph: 150 horsepower versus the outgoing TDI's 140 hp. Torque will be the same strong, diesel-appropriate 236 pounds-feet.

"It's an all-new engine, to all intents and purposes," Gillies said. "We're hoping that it will give a probably somewhere around 8% bump to highway [fuel] economy."

That could mean as high as 46 mpg in the Passat TDI, whose current EPA ratings with a six-speed manual are 31 mpg city, 43 highway and 35 mpg combined are the highest among VW's 2014 TDI four-cylinder models. But even the lowest 2014 -- the Beetle with six-speed automatic -- still is rated 29/39/32.

And diesels, unlike some other powertrains, tend to actually get the EPA estimate or better in the real world.

In a recent Michigan to Washington, D.C., highway run in a stickshift Passat TDI -- at the posted speed limits with a full load and AC on -- USA TODAY registered 53.5 mpg with no special effort.

Unfortunately, shoppers have to weigh the efficiency gains — inherent because diesel fuel has more energy per gallon than gasoline — with a higher fuel price, much of it due to higher federal and state taxes than for gasoline. A gallon of diesel averaged $3.88 nationwide today, according to AAA. That's 17 cents more than the price of regular unleaded at $3.61 and 6 cents less than $3.94 for premium.

Audi, the Volkswagen Group's upscale brand, also is likely to get the new engine. While most of its TDI models -- including the A6, A7 and A8 and Q5 (for 2014) -- use a 3.0-liter V-6 turbodiesel. Audi the outgoing A3 hatchback offers the 2-liter four-cylinder and Audi has confirmed the redesigned 2015 model will continue to offer a diesel four. Expect this to be it.