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To TDI or not TDI?

Audi A7 creates diesel/performance quandary

LOS ANGELES -- For the better part of a decade, automotive journalists have been chastising the American public for not making the smart decision and embracing diesel power.

Diesel seemingly has what every American wants: great low-end torque, refined tailpipe emissions and fantastic highway fuel economy on par with the best gasoline-electric hybrids.

But shoppers can’t seem to get the image of those clattering, unreliable diesels from the 1970s out of their heads. The diesel price premium -- similar to the premium paid for a hybrid -- doesn’t help either, especially when diesel fuel is more expensive than super-unleaded gasoline in many parts of the country. Is diesel worth it?

I decided to find out by driving back-to-back Audi A7 four-door coupes with gasoline and diesel engines to see which one stirred my heart more. The A7 was an ideal road-trip test bed, with a cavernous trunk to hold a week of luggage and several cases of Paso Robles zinfandel, and the über-cool MMI telematics system, including Google Street View.

For starters, both engines had a leggy nonchalance to waltz through a four-hour drive.

One caveat: The gasoline version was an S7, a performance model of the lithe full-sized hatchback boasting a 4.0-liter twin-turbo that poured forth 420 hp and 406 pounds-feet of unstoppable torque. Oh, and 16-inch ventilated front brakes. Imagine being flung out of a nightclub by a gang of particularly grumpy bouncers. All that joyous accelerative flight, and all that sudden decelerative force when your face hits the pavement.

To obtain that gusto, the S7 as tested priced out at $88,395, including shipping. During my one-week test from L.A. to Monterey and back -- much of it on the highway, but with scattered enthusiastic hilly drives -- the S7 returned 22 mpg. I had to refuel four times, and with super-unleaded well more than $4 a gallon in California, that got expensive quickly. But what price joy?

Performance merits

By contrast, Audi’s A7 TDI “clean diesel” was no wilting flower. It had its performance merits, too. Although the 3.0-liter single-turbo V-6 put out a relatively meager 240 hp, it generated a lusty 428 pounds-feet of torque. Sixty mph from a dead stop arrived in less than six seconds -- plenty fast for Joe Public.

There was an assured muscularity to the TDI’s power band, delivering a solid boot to the rump when asked. And while it couldn’t match the ridiculous force of the S7, especially in the midrange rpms, it wouldn’t surprise me if Audi’s head of diesel engineering was named Grunter Torkmeister. As for handling, even though the TDI didn’t have the S7’s sticky summer tires, it more than held its own on twisty roads.

The TDI as tested priced out at $81,395, a relative bargain compared with the S7. Although I didn’t put nearly as many miles on the TDI as the S7, the fuel economy for the 4,266-pound beast was an impressive 34 mpg, most of it in L.A.’s ragged city driving. I didn’t have to refuel all week.

When I returned the car, I asked the press fleet rep about longer-term drives. Coincidentally, he had recently done a similar run from L.A. to Monterey and back -- 650-plus miles -- on a single tank of diesel. Formidable.

So, which to choose? The TDI is considerably more expensive than a bog-stock A7 with a 3.0-liter gasoline engine, but it comes in $7,000 less than the S7. The enthusiast in me -- the one with the bank account that can afford $90,000 worth of Teutonic sturm und drang -- covets the S7. And if you can afford the car, you certainly can afford the frequent trips to the gas pump. But there was something utterly cool about miserly fuel economy with enough performance to satisfy 90 percent of the driving public, the only limit being that you have to stop to empty your bladder well before you need to refill the car’s.

My heavy-footed peers may scoff, but my vote goes to the TDI.

You can reach Mark Rechtin at -- Follow Mark on Twitter: @markrechtin

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