I recently rented a Mazda 3 5-door hatchback while on vacation in Spain. I arrived at the rental company's parking garage late at night, started the car, and retrieved from my briefcase the Mapquest directions I had printed before I left Ann Arbor.

I depressed the clutch pedal, put the shifter into first gear, and started moving toward the exit. I was surprised at the four-cylinder's low-rev torque, so I glanced down at the gauges. It wasn't until I saw the tachometer's 4750-rpm redline that I realized my Mazda was, in fact, a diesel.

Over the next 350 miles I thrashed the living daylights out of the little 3. I did several top-speed runs (over 115 mph indicated), thrashed it on mountainous back roads, and reveled in its controllable lift-off oversteer, taking every traffic circle as sideways as I possibly could.

Never once, neither when tootling around in traffic with five people on board and the A/C cranking or cruising down the highway at 80 mph, did I mind that I was in a diesel-powered car - the Mazda's quick steering and great composure made sure of that. And though my right foot was on the floor most of the time, the 1.6-liter's abundant torque never left me wanting for more.

The only surprise I had was when it was time to fill up: I had averaged 36 miles per gallon.

To put that in perspective, I've completed twenty-one road trips in the past year. Each time, I've tried to maximize my fuel economy by setting the cruise control at 79 mph and locking the transmission in top gear. Even under these super-mild conditions, not a single car has returned 36 mpg. And yet the Mazda 3 did so while being flogged mercilessly.

The most fuel-efficient Mazda 3 sold in the US is EPA rated at 24 mpg city, 32 highway - a far cry from 36. Had my Spanish-rental 3 been equipped with that engine, a 2.0-liter, 148-hp four-cylinder, it would have sucked down the five-dollar-per-gallon fuel at almost twice the rate it did.

My rental car was equipped with a 1.6-liter that produces 107 horsepower and 177 lb-ft of torque. Mazda says it can accelerate from zero to sixty in 11.5 seconds, but, like all diesel-engined cars, it feels much quicker because of its ultra-short gearing and gobs of torque. In European fuel economy testing, it returns 39 mpg city, 57 mpg highway. (The 2.0-liter gas engine that we get in the U.S. returns 22 / 37 on that same test.)

If I were buying a European-spec Mazda 3, the 1.6-liter's lack of performance would be an issue because I'm such a speed freak. Here's where it gets interesting: Mazda also offers a 2.0-liter turbodiesel. The bigger oil burner makes 7 hp less than the gasoline engine of the same size, but it makes 266 lb-ft of torque in place of the sparkplug-equipped gas engine's measly 135. It's slightly slower to 62 mph (9.9 seconds versus 9.1), but makes up for that with a higher top speed (126 mph versus 125.)

Even though it offers comparable performance compared to the gas engine, its fuel economy is in a different league. In the city, the diesel can travel 33 miles on each gallon of the stinky stuff - the gas car only goes 22. That's 50% better economy! Highway economy is 44 for the diesel, 37 for the gas-burner. And unlike hybrids, whose real-world fuel economy is dismal compared to the test results, diesel-powered vehicles tend to do even better. It's time to bring on the diesels. I, for one, am sick of "economy cars" returning highway fuel mileage in the 20s and 30s. Our Four Seasons Volkswagen GTI has been averaging 24 mpg on the highway. I would gladly trade in some of its performance for better fuel economy, and 57 miles per gallon in a Mazda 3 sounds like the perfect way to do so.

automobilemag.com