2011 Volkswagen Jetta TDI

If the Volkswagen Jetta TDI featured in our Battle Of The Eco Compact Cars comparison test looked familiar, that's because it's our long-term tester. In fact, you might say that the arrival of our Jetta TDI is what sparked the idea for the comparison test, especially after Editor-in-Chief John Neff took the car on a few long highway trips and recorded well over 50 miles per gallon. And while the Jetta – spoiler alert! – may not have won our eco-warrior comparison, its 2.0-liter diesel engine continues to impress us with its effortless efficiency.

Just how effortless? We enthusiasts tend not to be the most efficient drivers, and yet our recorded average fuel economy over the past 8,500 miles is 43.4 miles per gallon. That's right, our average combined number is 1.4 mpg higher than the EPA's highway rating for the Jetta TDI. In fact, we've recorded as high as 53.5 mpg on the highway, and even under the most spirited driving, the lowest number recorded in our logbook so far is just 36.7 mpg.

Keep your eyes locked on the official Autoblog Facebook page for the majority of our updates, as well as the official Autoblog Twitter account (@therealautoblog, look for the #ablongterm hashtag).

Jetta logbookSpeaking of logbook, that term gets thrown around quite often when referencing our long-term cars. The photo to the right shows the actual logbook that lives inside our Jetta TDI, where we record data like mileage, gallons of diesel consumed, cost of fill-ups and, of course, fuel economy.

Our most impressive fuel economy is yet to come, though. In August, the Jetta will make its big cross-country trek from Detroit to Los Angeles, and we'll likely achieve over 50 mpg a number of times during the multiple-day trip. Last year, our two long-term cars met in the middle of the country, and our old Jetta TDI Cup Street Edition only mustered up an average of 39.9 mpg (while being substantially more fun to drive in the process, natch).

Before the Jetta leaves for Los Angeles, we'll be taking it in for its first scheduled maintenance appointment. In addition to an oil change, we want to make sure the car is in tip-top shape for its cross-country commute. Suffice it to say, we won't be taking it to any old lube shop this time around.

Stay tuned for next month's update to read the full report about the Jetta's 2,300-mile journey.

Keep your eyes locked on the official Autoblog Facebook page for the majority of our updates, as well as the official Autoblog Twitter account (@therealautoblog, look for the #ablongterm hashtag).