We'll resist the urge to write the typical diesel intro. You know how it goes: "Most Americans think 'diesel' is synonymous with ?big clouds of black smoke,' but nowadays this couldn't be further from the truth!" Yes, that teaser worked in 2005, but these days we're well into the clean diesel era, as the legions of stateside Volkswagen TDI devotees will enthusiastically tell you. Thanks to the wonders of urea exhaust-stream injections and other advances, squeaky clean diesel emissions are a given in 2012. The question now is just how good the diesel can be.
Judging by the current crop, the answer is "very." Diesels have always had inherent advantages in fuel-efficiency and torque production, and contemporary turbocharging technology has narrowed the horsepower gap considerably. You'll still pay more for a diesel, not least because the U.S. government charges automakers an arm and a leg to certify these engines, but it increasingly seems to be worth the stretch. Want proof? Here are five leading examples of modern diesel power and all in dramatically different types of vehicles.
Let's start here with an overview. The recent arms race among diesel-powered pickups has been every bit as intense as muscle-car mania, with the "Big Three" American automakers endlessly angling to outdo one another. If we're honest, all of the three big-rig turbodiesels-Dodge's 6.7-liter inline-6, Ford's 6.7-liter V8, or GM's 6.6-liter V8-have more than enough oomph for any task short of, say, reversing the planet's rotation.
But even though the Ford V8 has the highest towing capability and the GM V8 is the quickest in a straight line, our favorite is Dodge's venerable Cummins straight-six. Unlike the Ford motor, this one's been around for years, so it's battle-tested. And unlike either rival, the Cummins can be had with a proper manual transmission, which is something that certain truck guys still appreciate. Granted, you lose some muscle if you get the stickshift; whereas the automatic Cummins ties the Ford for the segment lead at a preposterous 800 pound-feet of torque, the manual version is limited to 610 lb-ft. Also, the Cummins is stuck on 350 horsepower while the others crank out 400 horses (well, 397 in the GM V8's case). Still, we'll take proven durability and multiple transmission options every day of the week.
You expect to find diesels in German SUVs, and sure enough, Mercedes-Benz offers diesel versions of both the M-Class and GL-Class crossovers. But you don't necessarily expect to find them in German luxury sedans (at least not in the US), which is why we're shining the spotlight on Mercedes' excellent E350 BlueTEC. The recently redesigned E-Class is a throwback in some respects, a bona fide highway cruiser that gobbles up miles like big Benzes of yore. The "BlueTEC" 3.0-liter turbodiesel V6, however, is decidedly modern, delivering its substantial 210 horsepower and 400 pound-feet of torque with hardly a trace of clatter or vibration. The efficiency is there as well: at 21 mpg city and 32 mpg highway, the E350 BlueTEC gives you almost four-cylinder fuel economy along with that V8-grade torque.
As noted, Volkswagen has been selling its "TDI" diesels stateside for quite a while now, but they haven't always been gratifying to drive. The horsepower ratings of early four-cylinder TDIs didn't even crack triple digits, so performance compromises were obviously required. No longer, though, as the current 2.0-liter iteration of the TDI inline-4 is rated at 140 horsepower and 236 pound-feet of torque-enough juice to leave many four-cylinder gasoline engines in the dust. Now, it may seem strange to think of a diesel in a jaunty little thing like the redesigned Beetle, but the TDI four is actually pretty magical in compact applications, cranking out that ample torque with a palpable sense of purpose. Like the Golf on which it's based, the Beetle TDI will break through the magical 40-mpg barrier.
Yes, yes, we know-that's two VWs in a row. But we're calling out the Passat TDI for two solid reasons. First, there's not another affordable diesel-powered family sedan on the market, so the Passat was going to get the nod here unless it turned out to be completely terrible (which it's completely not). But more interestingly, the Passat TDI makes our list because it proves that a diesel engine's trademark torque can easily overcome an apparent power deficit. The TDI in question is the same four-cylinder version that the Beetle employs, so it makes the same 140 horsepower, by far the lowest figure among current family sedans. Yet the Passat TDI never feels underpowered. Why? Because those 236 pound-feet of torque are fully engaged from just 1,750 rpm, so there's no downshifting required; just squeeze the throttle and away you go - something we regularly enjoy in our Long Term VW Jetta TDI. Surprisingly-and perhaps due to some year-to-year variations in EPA testing conditions-the sizable Passat TDI gets the best fuel economy of any TDI vehicle for 2012, clocking in at 31 mpg city and 43 mpg highway with the manual transmission (the Golf and Jetta yield 30/42).
We'll preface this one by saying, "Believe it when you see it." We've heard a lot of stories over the years about diesels coming to America, and trust us, they don't always pan out. But we have it on good authority that Mazda's endearing new compact crossover, the Mazda3-based CX-5, will indeed be available with a 2.2-liter turbodiesel inline-4 in the not-too-distant future. Official U.S. output numbers have not been released, but rumor has it that the "Skyactiv-D" diesel four will produce 175 horsepower and over 300 pound-feet of torque, handily outdoing VW's 2.0-liter TDI. Could this be the first crossover to crest 40 mpg? We're looking forward to finding out.