BMW 335 Sedan

BMW wants you to know it’s paying attention. As a company whose cars are aimed at people who enjoy performance driving, some consumers may feel that it’s out of step with all things green.

The Munich-based automaker has an answer to that: “EfficientDynamics” -- two capitals, no space -- which is public-relations speak for cars that burn less fuel but aren’t a total bore to drive.

Next week’s Frankfurt Auto Show will showcase a BMW concept vehicle powered by a three-cylinder turbo-diesel engine and two electric motors -- basically a plug-in, hybrid sports car.

Cool stuff, but don’t look for it at your dealership next autumn. If you’re shopping for a fun, Earth-cuddling Bimmer today and not in a “Blade Runner” future, you’ll have to go old school, oddly.

Step one: Look at BMW’s best-selling models, the 3 Series and the X5 SUV, and then consider a fuel that most Americans gave up ages ago -- diesel.

Two out of every three BMWs sold in Europe are diesels, and BMW calculates that its European fleet already nearly achieves the U.S. mandate for 2016 of 35.5 miles per gallon. In the U.S., BMW sells the 335d sedan and the X5 xDrive35d, which are capable of 550 or more miles on a single tank.

Audi, Volkswagen and Mercedes-Benz are also pushing their diesels stateside, capitalizing on successes in Europe. My pick for favorite efficient car last year was the VW Jetta TDI, and I’m looking forward to Audi’s release of its A3 TDI, which is supposed to get 42 miles per gallon on the highway.

Price Premium

Opting for a diesel is a game of give and take. There’s a price premium: BMW’s $44,725 sedan and the $52,025 SUV cost at least $3,600 more than their gasoline-burning counterparts. Balanced against that, the Internal Revenue Service is giving a tax credit of $900 and $1,800 on the 335d and X5 diesel respectively, and BMW has an “eco credit” of $4,500 off both vehicles’ final prices.

In terms of performance, you’ll sacrifice horsepower but gain loads of extra torque, the hallmark of diesel engines (and the reason why heavy tractor-trailers use them).

In this new era of cleaner diesel engines that use sophisticated urea and scrubbing systems, you’ll release 20 percent less carbon dioxide while getting as much as 30 percent better gas mileage on the highway.

Both BMW diesels get the same engine, a 3.0-liter, twin- turbo, inline six-cylinder. The 335d wins the battle of the fun as it weighs some 1,400 pounds less than its big brother. As the most fuel-efficient BMW ever sold in the U.S., it drinks 23 mpg city and 36 highway, but still scoots to 60 mph in six seconds. That’s 10 mpg better than the gasoline engine on the open road.

In my tests, I saw an average of 32 mpg in mixed driving.

Different Experience

While it looks the same as the regular 3 Series, the driving experience is markedly different. The 335i gas version has a 300-horsepower, twin-turbo six, which soars to 7,000 rpm at redline and has a clean, endless stream of power. It practically sings arias.

Conversely, the diesel is all basso profundo, flush with power at the lower registers, but meek above 4,500 rpm. While it has only 265 horsepower, the massive 425 pound-feet of torque is available at a mere 1,750 rpm.

That extra grunt means the 335d comes on like a bull when you slap the accelerator, bouncing out of a standstill as if it were a muscle car. And it’s content to stay at those lower registers: Even at extra-legal highway speeds you’ll rarely see 3,000 rpm on the tachometer.

X5 Disappoints

In comparison, the X5 is a slight disappointment. The thrill of that low-end power is negated by all the extra heft. It will still make 60 mph in a respectable 6.9 seconds, though the fun factor is much paler.

The good news is that once you are up to speed, there’s a pleasant sense of sturdiness to the thrum of the engine. Engineers have done a good job of matching the gearing to its ample weight and the balanced delivery of power feels coherent and thoroughly BMW.

On a recent drive up to Connecticut’s Lime Rock racetrack, the X5 handled both highway speeds and back roads admirably, even in heavy rain. Part of this is a result of its all-wheel- drive, which is standard, but also because of the steady torque on demand.

Best of all, I averaged 23 mpg, which is pretty extraordinary for a vehicle which weighs more than 5,000 pounds, and is in line with Environmental Protection Agency estimates of 19 city, 26 highway. The regular X5 manages only 15 and 21.

Ultimately the best argument may be the fact that, for a range of about 550 miles, I’ve been able to ignore the fuel pump completely. Fewer fill-ups in any vehicle is a glorious thing.

The 2009 BMW 335d Sedan and X5 xDrive35d SUV at a Glance

Engines: 3.0-liter twin-turbo inline diesel six-cylinder with 265 horsepower and 425 pound-feet of torque.

Transmissions: Six-speed automatic.